HoldsUp

Chris Williamson · 2026-01-05 · Andrew Huberman, Chris Williamson (host)

These Habits Are Much Better than People Realise - Dr Andrew Huberman (4K)

71 claims checked against research: 3 contradicted 13 overstated 6 needing context 36 supported 2 corroborated online 11 unverified

3

Contradicted by research

0:08:35Andrew Hubermancontradictedhigh

Most people with Cushing's syndrome have pathologically low cortisol early in the day and pathologically high cortisol late in the day.

"Most people, even people with Cushing's, have pathologically low cortisol early in the day, pathologically high cortisol late in the day." (said at 0:08:35)

The claim that patients with Cushing's syndrome have pathologically low cortisol early in the day is contradicted by established clinical evidence. Cushing's syndrome is characterized by autonomous, excessive cortisol secretion and a disruption of the normal circadian rhythm. Diurnal cortisol profile studies show that early-morning cortisol in patients with Cushing's syndrome is either elevated or within normal ranges, and significantly higher than in healthy controls across all time points, rather than pathologically low. The hallmark circadian abnormality in Cushing's syndrome is the failure of cortisol to decline to its normal nadir at late night (resulting in pathologically high late-night cortisol), not early-day cortisol deficiency.

0:11:38Andrew Hubermancontradictedhigh

A full moon at its brightest produces only about 1 to 5 lux of illumination.

"A bright full moon, where you say, 'Oh, it's so bright out,' is actually only about 1 to 5 lux." (said at 0:11:38)

The speaker claims that a bright full moon provides about 1 to 5 lux of illumination. In physical and chronobiological literature, illuminance from a clear-sky full moon at ground level is considerably lower, typically measuring between 0.05 and 0.3 lux (well below 1 lux). Studies measuring natural nighttime photic environments note that twilight light levels (50 to 2,000 lux) are 2 to 4 orders of magnitude brighter than the illuminance provided by a full moon, and that nocturnal illumination under moonlight and starlight is measured at fractions of a lux.

0:20:05Andrew Hubermancontradictedvery low

Rodent studies suggest that the peptide pinealon can regenerate pinealocytes in the pineal gland.

"there are things like the the peptide pinealon I experimented with a bit. Um not a not a lot of human studies at all, um some interesting rodent studies may regenerate the pinealocytes in the in the pineal." (said at 0:20:05)

The speaker appears to have confused Pinealon (the tripeptide Glu-Asp-Arg, typically studied as a brain/cortex bioregulator) with Epitalon (the tetrapeptide Ala-Glu-Asp-Gly, a pineal bioregulator). In an in vitro study evaluating short peptides on organotypic pineal gland cultures from rats, Ala-Glu-Asp-Gly (Epitalon) tissue-specifically stimulated the proliferative marker Ki-67 and secretory activity in pinealocytes, whereas Glu-Asp-Arg (Pinealon) did not stimulate these proliferative or secretory markers.

13

Overstated

0:06:12Andrew Hubermanoverstatedmoderate

Intense exercise in the late afternoon or evening can triple or quadruple baseline cortisol levels for several hours.

"if you were to do uh say a very intense workout in the late afternoon, evening, it's been demonstrated that will triple or quadruple your baseline cortisol levels for a few hours" (said at 0:06:12)

Acute high-intensity exercise performed in the evening does stimulate the hypothalamic-pituitary-adrenal axis and transiently increase cortisol levels above pre-exercise baseline. However, the claim that it triples or quadruples baseline cortisol levels for several hours significantly overstates both the magnitude and duration of this response. In controlled crossover studies evaluating high-intensity interval exercise (HIIE) in the evening, post-exercise salivary cortisol increases modestly (e.g., ~33%, from ~1.56 to 2.34 ng/mL) rather than by 300% to 400% (3- to 4-fold), and typically returns toward baseline within 60 to 120 minutes.

0:41:10Andrew Hubermanoverstatedvery low

Sleeping in a lateral position (on the side) provides more effective glymphatic clearance in the brain than sleeping on one's back.

"Sleeping on your side, right or left side doesn't seem to matter, with the head slightly tilted does seem to be the preferable position. So all you back sleepers like me—some people—" (said at 0:41:10)

A landmark 2015 study in The Journal of Neuroscience demonstrated that glymphatic transport and amyloid-beta clearance were most efficient in the lateral position compared with supine or prone positions. However, this research was conducted exclusively in anesthetized rodents using dynamic contrast-enhanced MRI, radiotracers, and optical imaging. While physiological hypotheses exist regarding human venous drainage, direct human experimental evidence confirming superior glymphatic clearance in the lateral versus supine position is lacking.

0:50:20Andrew Hubermanoverstatedlow

Research by David Spiegel demonstrates that approximately 25% of individuals who undergo clinical hypnosis for smoking cessation remain abstinent after a single session for life.

"They had 25% of people that do hypnosis for smoking cessation have it in one session for life." (said at 0:50:20)

In a 1993 study led by David Spiegel, 226 smokers underwent a single-session habit-restructuring intervention utilizing self-hypnosis. The study found that 52% achieved complete abstinence at 1 week and 23% maintained continuous abstinence at the 2-year follow-up. While approximately one-quarter of participants remained abstinent, the follow-up period was 2 years rather than "for life," making the claim's long-term duration overstated. Additionally, the study was an uncontrolled observational cohort, and systematic reviews (e.g., Cochrane) indicate that evidence for the specific efficacy of hypnotherapy over other smoking cessation interventions remains of low to very low certainty.

1:18:33Andrew Hubermanoverstatedlow

The anterior midcingulate cortex is a highly plastic brain structure that can grow and be engaged by effort, tenacity, and willpower.

"the anterior midcingulate cortex existed to know that there's this thing called tenacity and willpower. I think that the fun twist is that um it's a highly plastic structure that we can engage and grow and um and that reinforces the the sets of behaviors that are that are involved" (said at 1:18:33)

Neuroimaging reviews and cognitive neuroscience literature identify the anterior midcingulate cortex (aMCC) as a critical hub involved in tenacity, effort-based decision making, and cost-benefit computations required to overcome challenges and achieve goals. Furthermore, cross-sectional neuroimaging studies have found preserved aMCC cortical thickness in 'superagers' (older adults with youthful memory and tenacity). However, the assertion that the aMCC is a highly plastic structure that directly 'grows' in size or thickness in response to voluntary willpower or effortful behavior is a theoretical extrapolation of cross-sectional and correlational neuroimaging data, lacking robust longitudinal trial evidence showing causal structural growth from effort.

1:28:59Andrew Hubermanoverstatedvery low

Methamphetamine consumption causes a thousandfold increase in dopamine release within moments.

"something like methamphetamines right is going to what a thousandfold increase in dopamine within moments." (said at 1:28:59)

Preclinical microdialysis studies demonstrate that methamphetamine administration produces massive increases in extracellular striatal and accumbens dopamine, typically reaching approximately 1,000% to 1,500% of baseline (a 10- to 15-fold increase), and up to ~7,000% (a 70-fold increase) following neurotoxic high doses in rodents. A 'thousandfold' increase (1,000-fold, or 100,000%) confuses a 1,000% increase with a 1,000-fold increase, overstating the actual magnitude by several orders of magnitude.

1:41:20Andrew Hubermanoverstatedlow

Particulate matter air pollution is a primary contributing factor to the development of dementia.

"now we're hearing a lot about the particulate in certain air pollution, you know, might be one of the primary uh players in in causing dementia" (said at 1:41:20)

Particulate matter air pollution (such as PM2.5) is an established environmental risk factor associated with an increased risk of dementia, but describing it as a primary cause or driver overstates its role. Large systematic reviews and meta-analyses of longitudinal cohort studies demonstrate modest associations (e.g., a hazard ratio of ~1.03 to 1.04 per standard increment in PM2.5 exposure). The primary non-modifiable risk factors for dementia remain advanced age and genetic susceptibility (such as the APOE-e4 allele), while major modifiable risk factors include midlife hypertension, hearing loss, obesity, smoking, physical inactivity, and diabetes, with air pollution contributing as one of many recognized modifiable risk factors.

2:13:16Andrew Hubermanoverstatedvery low

Magnesium bisglycinate and magnesium L-threonate cross the blood-brain barrier more readily than other forms of magnesium.

"Magnesium L-threonate or bisglycinate... bisglycinate and and threonate cross the blood-brain barrier more readily." (said at 2:13:16)

The speaker bundles assertions about two magnesium formulations. For magnesium L-threonate, preclinical animal research demonstrates that oral administration increases brain and cerebrospinal fluid magnesium concentrations and enhances synaptic plasticity more effectively than other inorganic magnesium salts (e.g., Slutsky et al., 2010). However, this finding is based primarily on rodent models and has not been established in direct human blood-brain barrier pharmacokinetic studies. For magnesium bisglycinate, no published comparative pharmacokinetic studies demonstrate superior blood-brain barrier penetration or enhanced central nervous system accumulation compared to other magnesium compounds. Because the claim asserts superior blood-brain barrier crossing for both forms as an established fact, it is overstated.

2:14:00Andrew Hubermanoverstatedlow

Magnesium in the cochlear endolymph is depleted by loud sound, and magnesium supplementation protects against acoustic trauma and permanent hair cell loss.

"Magnesium protects against hearing loss. Why? The endolymph in which the hair cells that vibrate in response to sound the that endolymph is like a thick kind of fluid, viscous fluid is magnesium is is a prominent feature of that endolymph and it gets depleted by very loud sound to some extent. But encouraging more magnesium in the endolymph is protective against hair cell loss, which is hearing loss, which is permanent." (said at 2:14:00)

Experimental animal models demonstrate that higher cochlear magnesium levels and magnesium supplementation (often in combination with antioxidant vitamins) can attenuate noise-induced auditory threshold shifts and promote sensory hair cell survival by mitigating oxidative stress. However, the speaker overstates the certainty and mischaracterizes the physiological mechanism. Endolymph is primarily characterized by a high potassium concentration, containing only low millimolar levels of magnesium (~0.8–1.1 mM). Furthermore, comprehensive reviews of the human literature note that while experimental and animal data are extensive, high-quality clinical evidence in humans for preventing noise-induced hearing loss remains limited and conditional.

2:15:40Andrew Hubermanoverstatedmoderate

Re-analyses of moderate alcohol consumption studies show that control groups were improperly constructed and that zero alcohol intake is healthier than moderate intake.

"Keith Humphreys and and colleagues at Stanford did an analysis of all those previous papers and essentially found that the control groups in those studies that concluded moderate drinking is good for you were completely off. They were they were comparing sick people to less sick people in one case. And it turns out that when you when you normalize for the for proper controls and you look at all the studies, you do the meta-analysis, without fail zero is better than any." (said at 2:15:40)

Large systematic reviews and meta-analyses of prospective cohort studies confirm that earlier observational literature suffered from significant control-group bias (specifically 'abstainer bias' or 'sick-quitter bias', where former drinkers and individuals in poor health were misclassified as non-drinkers, making moderate drinkers appear comparatively healthier). However, when meta-analyses correct for reference-group misclassification and study design characteristics, low-to-moderate alcohol consumption is found to have no significant protective benefit or difference in all-cause mortality compared to lifetime abstention (e.g., relative risk 0.93 to 0.97, not statistically significant), rather than demonstrating that zero intake is definitively superior to moderate intake. Significant increases in mortality risk emerge primarily at higher consumption levels.

2:32:55Andrew Hubermanoverstatedmoderate

In IVF, embryos failing to develop past day three into a blastocyst are typically attributed to sperm quality.

"We talk about quality of sperm because this definitely plays a role in terms of what are called day three crashes. You know, when the embryo doesn't get doesn't even become a blastocyst, it doesn't get past day three. That's typically attributed to the sperm." (said at 2:32:55)

In human embryology, early cleavage divisions (days 1–3) are primarily regulated by maternal RNA and proteins stored in the oocyte, while major embryonic genome activation (EGA) occurs around the 4- to 8-cell stage (day 3). Because paternal genes are first expressed during EGA, paternal factors (such as sperm DNA fragmentation or chromosomal abnormalities) can become manifest after day 3 and contribute to blastocyst arrest. However, claiming that failure to develop past day 3 is "typically attributed to the sperm" overstates the paternal role: large genomic and embryological studies demonstrate that blastocyst failure is multifactorial, with maternal aneuploidy, oocyte cytoplasmic/mitochondrial quality, and chaotic mitotic errors occurring independently of parental origin accounting for a major portion of post-day 3 developmental arrests.

2:36:25Andrew Hubermanoverstatedvery low

Research by Catherine Dulac demonstrated that specific brain regions exhibit parent-of-origin monoallelic gene expression, expressing genes exclusively from the mother or the father.

"there's a woman whose laboratory is at Harvard named Catherine Dulac, who's a luminary in the field of neuroscience, who uh did some beautiful experiments showing that different brain areas are genetically identical to mom or to dad. Even in you and me, you have entire brain areas that are 100% the genes from dad. It's not It's a myth that every cell is a is a 50-50 mix of genes from mom." (said at 2:36:25)

Research from Catherine Dulac's laboratory (such as Gregg et al., Science 2010, and Perez et al., eLife 2015) identified parental expression biases and parent-of-origin monoallelic expression across hundreds of specific genes and transcript isoforms in the mouse brain, with patterns varying across developmental stages and brain regions. However, claiming that 'entire brain areas are 100% the genes from dad' or 'genetically identical to mom or to dad' significantly overstates the biological findings. Cells across all brain regions retain both maternal and paternal genomes, the majority of autosomal genes are expressed biallelically from both parents, and parent-of-origin imprinting affects only a defined subset of genes and loci.

2:48:38Chris Williamson (host)overstatedlow

The pathogenesis of autoimmune disease requires a triad of genetic predisposition, a permeable gut lining, and an environmental trigger.

"And then when you get into autoimmune, all you need for autoimmune is genetic predisposition, permeable gut lining, and environmental stressor." (said at 2:48:38)

The idea that autoimmune disease pathogenesis hinges on a triad of genetic susceptibility, environmental triggers, and increased intestinal permeability ("leaky gut") is a theoretical paradigm prominently proposed by researcher Alessio Fasano. While preclinical and clinical evidence supports a role for intestinal barrier dysfunction in conditions like celiac disease and type 1 diabetes, claiming that this triad is definitively "all you need" oversimplifies autoimmune pathogenesis. Autoimmune disorders are multifactorial, involving complex immune system dysregulation, epigenetic modifications, and microbiome interactions, and an intestinal permeability defect has not been demonstrated as a universal causal requirement across all autoimmune diseases.

5:03:54Chris Williamson (host)overstatedmoderate

A single male black-footed ferret helped save the species from extinction by repopulating a breeding colony.

"you then decided to peel off to give me like a miniature novel about a black ferret who repopulated an entire like female colony of ferrets and this entire He saved the species." (said at 5:03:54)

The host's description overstates the breeding history of the black-footed ferret (*Mustela nigripes*). The captive breeding and recovery program was established from 18 individuals captured near Meeteetse, Wyoming, in the mid-1980s, seven of which became founders that successfully reproduced. While individual male founders contributed significantly to the captive lineage, the species recovery was not accomplished by a single male repopulating a female colony on his own. In addition, modern management has utilized artificial insemination using cryopreserved semen from multiple banked males to maintain genetic diversity.

6

Needs context

0:03:02Andrew Hubermanneeds contextmoderate

In chronic caffeine users, caffeine consumption does not significantly increase cortisol levels.

"Turns out caffeine, if you're a chronic caffeine user, such as me, such as you, doesn't actually increase cortisol that much." (said at 0:03:02)

Randomized crossover evidence indicates that chronic daily caffeine consumption induces partial tolerance to caffeine's cortisol-stimulating effects. In a controlled trial of healthy adults, 5 days of habitual caffeine intake (300 to 600 mg/day) abolished the salivary cortisol response to a morning caffeine challenge, whereas abstinent individuals showed robust cortisol increases. However, tolerance is incomplete: repeated doses taken later in the day or caffeine consumed during acute psychosocial stress can still elicit significant cortisol elevations in habitual consumers.

0:03:18Andrew Hubermanneeds contextmoderate

Cold water immersion in a cold plunge reduces cortisol levels while increasing adrenaline, dopamine, and norepinephrine.

"Cold plunge reduces your cortisol levels. You can look at the data. The data show that it goes down. Adrenaline goes up. Dopamine goes up. Norepinephrine goes up." (said at 0:03:18)

The claim is partially accurate but needs qualification regarding cortisol and adrenaline. The widely cited study on cold water immersion (Šrámek et al., 2000; PMID: 10751106) evaluated 1-hour immersion in water at 14 °C and found large increases in plasma noradrenaline (by 530%) and dopamine (by 250%). In that trial, cortisol concentrations did not rise and tended to decrease (as is typical with head-out water immersion due to hydrostatic pressure), while plasma adrenaline remained unchanged. However, other cold-exposure and winter-swimming protocols show variable responses: acute cold stress can elevate or leave adrenaline unchanged, and cortisol levels can either decline due to immersion hydrostatic effects/circadian rhythm or increase transiently during more severe or painful cold stress. Thus, while dopamine and norepinephrine robustly increase, cold water immersion does not uniformly reduce cortisol or increase adrenaline across all contexts.

0:25:58Andrew Hubermanneeds contextmoderate

Switching from a standard macronutrient diet containing starches to a low-carbohydrate diet significantly increases cortisol levels.

"But if you shift from a sort of standard macronutrient distribution of, you know, 40/30 or whatever it is where you're eating starches to a low-carbohydrate diet, your cortisol levels go up significantly. This has been explored." (said at 0:25:58)

Meta-analytic evidence indicates that transitioning from a high-carbohydrate to a low-carbohydrate diet (≤35% carbohydrates) moderately elevates resting cortisol during the acute adaptation phase (<3 weeks) and amplifies cortisol release following prolonged exercise. However, in longer-term interventions (≥3 weeks), resting cortisol levels do not remain significantly elevated and return toward baseline.

0:25:30Andrew Hubermanneeds contextmoderate

After three weeks or more on a low-carbohydrate diet, baseline cortisol levels remain consistently higher across the 24-hour cycle than on a carbohydrate-containing diet.

"If you're on a low-carbohydrate diet for a period of time, I think in this case it was 3 weeks or more, your cortisol curve, that high in the morning, low in the afternoon and evening, kind of normalizes a bit. It's still a little bit higher at every point than it normally would be." (said at 0:25:30)

Evidence from controlled feeding trials indicates that adhering to a very low-carbohydrate diet for several weeks (such as 4 weeks) significantly increases 24-hour cortisol excretion compared with isocaloric higher-carbohydrate diets. In a randomized 3-way crossover trial in overweight and obese adults (Ebbeling et al., 2012; PMID: 22735432), a very low-carbohydrate diet (10% carbohydrates) maintained over 4-week periods resulted in significantly higher 24-hour urinary cortisol levels (P = .005) compared to low-glycemic and low-fat diets. While this reflects an overall elevation in 24-hour cortisol output, the measurement in such pivotal trials was total 24-hour urinary excretion rather than repeated continuous salivary/serum sampling proving elevations at every individual diurnal timepoint.

  • partial: Effects of dietary composition on energy expenditure during weight-loss maintenance. (JAMA 2012) · cited 433x in the literature
    "Hormone levels and metabolic syndrome components also varied during weight maintenance by diet (leptin, P < .001; 24-hour urinary cortisol, P = .005; indexes of peripheral [P = .02] and hepatic [P = .03] insulin sensitivity; high-density lipoprotein [HDL] cholesterol, P < .001; non-HDL cholesterol, P < .001; triglycerides, P < .001; plasminogen activator inhibitor 1, P for trend = .04; and C-reactive protein, P for trend = .05), but no consistent favorable pattern emerged." (abstract, results, passage verified)
    pubmedfull study (doi)
2:46:52Andrew Hubermanneeds contextmoderate

Lichen planus is an autoimmune condition that causes bruise-like lesions on the wrists, genitals, and tops of the feet triggered by excessive stress and sleep deprivation.

"it's an autoimmune condition where the immune system because of stress and excessively long days, etc., excessive caffeine, push, push, push, people will get um it's almost like looks like bruising um on the wrists. They can get them on their genitals, on the tops of their feet." (said at 2:46:52)

Lichen planus is a chronic immune-mediated/autoimmune inflammatory disorder characterized by pruritic, flat-topped, polygonal, violaceous (purple) papules and plaques that commonly affect the flexor surfaces of the wrists, extremities (including dorsal aspects of feet/legs), and genital or oral mucosa. While psychological stress is frequently reported as an exacerbating factor or trigger for disease flares, asserting that it is directly caused by excessive caffeine, long work days, or sleep deprivation is an oversimplification and not established as a primary etiology.

  • context: Diagnosis and treatment of lichen planus. (American family physician 2011) · cited 56x in the literature
    "Lichen planus is a chronic, inflammatory, autoimmune disease that affects the skin, oral mucosa, genital mucosa, scalp, and nails. Lichen planus lesions are described using the six P's (planar [flat-topped], purple, polygonal, pruritic, papules, plaques). Onset is usually acute, affecting the flexor surfaces of the wrists, forearms, and legs." (abstract, results, passage verified)
    pubmed
2:46:10Andrew Hubermanneeds contextvery low

Finasteride taken for hair loss can lead to post-finasteride syndrome, causing persistent sexual and psychological health issues after cessation.

"young men who took drugs for to avoid hair loss: post-finasteride syndrome. You know, the medical community, the standard medical community thinks it's it's nonsense. But you talk to these guys that are having serious and at least till now permanent—hopefully some of this stuff can be reversed—sexual sexual health issues, psychological issues." (said at 2:46:10)

Post-finasteride syndrome (PFS) is described in the medical literature as a constellation of persistent sexual dysfunction (such as decreased libido and erectile dysfunction), somatic, and neuropsychiatric/psychological symptoms that endure after discontinuing finasteride taken for androgenetic alopecia. The speaker accurately notes both the existence of patients reporting these persistent symptoms and the widespread skepticism within mainstream medicine. However, the evidence supporting PFS as a distinct, causally established biological entity remains very low in certainty, relying primarily on patient surveys, pharmacovigilance reports, and uncontrolled case series with high potential for selection bias and nocebo effects, without confirmation from prospective randomized trials.

36

Supported by research

0:01:45Andrew Hubermansupportedmoderate

Viewing bright light in the first 60 to 90 minutes after waking can increase the morning cortisol spike by up to 50%.

"there's this unique opportunity in the first hour, maybe 90 minutes, but in the first hour after waking where viewing bright light can increase your morning cortisol spike, as I'll refer to it, by up to 50%." (said at 0:01:45)

Controlled laboratory studies show that morning bright light exposure enhances the cortisol awakening response (CAR) and morning cortisol levels. In experimental trials, transition from dim to bright light during early morning hours produced an immediate increase in cortisol concentrations of over 50% compared to dim conditions, and post-awakening exposure to bright or short-wavelength (blue/green) light during the first 45 to 60 minutes significantly amplifies the morning cortisol peak compared to dim or red light.

0:16:25Andrew Hubermansupportedhigh

Cortisol, unlike adrenaline, can cross the blood-brain barrier.

"And cortisol, unlike adrenaline, can pass through the blood-brain barrier." (said at 0:16:25)

Published neuroendocrine literature confirms that peripheral catecholamines such as adrenaline (epinephrine) do not readily cross the blood-brain barrier due to their polar structure, whereas lipophilic steroid hormones such as cortisol readily cross the blood-brain barrier to bind central receptors and influence neural circuitry.

0:29:34Andrew Hubermansupportedmoderate

Slow rocking of a bed helps individuals fall asleep.

"And we know, and there are great data showing, that a very slow rocking of a bed will help put you to sleep." (said at 0:29:34)

Multiple randomized crossover polysomnography studies demonstrate that gentle, slow lateral rocking of a bed (typically at ~0.25 Hz) promotes sleep onset and maintenance. In healthy adults undergoing full-night recordings or afternoon naps, continuous slow rocking significantly shortened latency to non-rapid eye movement (NREM) sleep, increased N3 slow-wave sleep duration, and reduced night awakenings via neural entrainment of sleep oscillations. While one small trial in young healthy men with very high baseline sleep efficiency did not detect a statistically significant change in sleep onset latency, overall experimental laboratory evidence supports that slow rocking facilitates the transition from wake to sleep.

0:38:10Andrew Hubermansupportedhigh

The lymphatic ducts empty collected lymph into the vascular system immediately below the clavicles.

"It's actually because the lymphatic ducts drain back into the—essentially dump all the lymph that's been surveilled by your immune system, etc., back into the vascular system just below your clavicles." (said at 0:38:10)

Standard human anatomical evidence confirms that the major lymphatic ducts (the thoracic duct and right lymphatic duct) empty collected lymph back into the venous blood circulation at the junction of the internal jugular and subclavian veins (the jugulosubclavian angle or subclavian vein), located at the root of the neck directly adjacent to and beneath the clavicles.

0:39:41Andrew Hubermansupportedlow

The brain's glymphatic clearance mechanism, in which perivascular spaces expand during sleep to clear waste via cerebrospinal fluid, was discovered and published around 2012.

"And it was discovered some years ago, 2012. It was actually discovered prior, but as science goes, it was kind of suppressed, and then it was finally discovered that during sleep, in particular deep sleep, the story goes, the spaces around the vasculature of the brain get bigger. Okay? You have these little cell types in the brain called astrocytes." (said at 0:39:41)

The speaker accurately describes the timeline and core mechanism of the glymphatic clearance pathway. In 2012, researchers led by Maiken Nedergaard characterized the brain's paravascular clearance pathway, demonstrating that cerebrospinal fluid (CSF) exchanges with interstitial fluid via astrocytic aquaporin-4 (AQP4) water channels to clear metabolic waste, including amyloid beta (PMID: 22896675). In a closely following 2013 study, the same group demonstrated in mice that natural sleep or anesthesia expands the brain's interstitial space by 60%, significantly increasing convective CSF-interstitial fluid exchange and waste clearance (PMID: 24136970).

0:46:15Andrew Hubermansupportedlow

The retina in the posterior chamber of the eye shares the same glymphatic clearance pathway as the brain.

"And the posterior chamber of the eye, which is where the light-sensing tissue is, the retina, actually shares the same glymphatic clearance system as your brain." (said at 0:46:15)

Research demonstrates that the retina and optic nerve participate in an ocular glymphatic clearance pathway that connects directly with the central nervous system's glymphatic system. Fluid and metabolic waste from the retina are cleared along the optic nerve via perivascular spaces and glial water channels (aquaporin-4) in communication with cerebrospinal fluid pathways from the brain. While the anatomical concept and its bidirectional transport have been characterized primarily in animal models and preclinical studies, emerging human imaging data also support this interconnected waste clearance system.

0:55:20Andrew Hubermansupportedhigh

Reading a text once and then self-testing produces significantly greater retention than reading the same passage multiple times without testing.

"Because if you have people read a passage one, two, three, four, five times versus one time and they self-test, one time and self-testing is significantly better." (said at 0:55:20)

The claim is supported by extensive psychological research on the 'testing effect' (or retrieval practice). Classic experimental studies (such as Roediger & Karpicke, 2006) demonstrate that reading a passage once and engaging in retrieval testing produces significantly greater long-term retention on delayed tests (e.g., after 2 days or 1 week) compared to repeatedly studying/reading the material without testing. Meta-analytic evidence further confirms that testing yields robust memory benefits over restudying across various educational and prose materials.

0:40:40Andrew Hubermansupportedhigh

Muscular movement and low-level muscular contractions drive the clearance and flow of lymph in the peripheral body against gravity through one-way valves.

"muscular movement clears lymph in the body, okay? So you need to walk. Low-level muscular contraction essentially moves the lymph up because it's fighting gravity. These are one-way valves. It brings it in from your limbs, and it essentially dumps it back eventually into the blood supply." (said at 0:40:40)

The speaker accurately describes established human lymphatic physiology. The clearance and centripetal flow of lymph from peripheral limbs back to the venous circulation against gravity relies on a combination of intrinsic pumps (spontaneous contractions of lymphatic vessel smooth muscle) and extrinsic passive pumps (notably skeletal muscle contraction and tissue compression during physical activity like walking), aided by one-way intraluminal valves that prevent backflow.

0:47:50Andrew Hubermansupportedlow

The dietary transition to soft, packet-based foods and baby foods has altered craniofacial development, leading to widespread orthodontic issues and smaller jaws.

"They were the ones that wrote the book Jaws—not the Jaws—with foreword by Robert Sapolsky. Jared Diamond, I think, wrote the introduction. These are heavy-hitter, serious science academics, and they were the ones that talked about the transition to soft foods, to packet-based foods, to baby food has created this kind of massive explosion in the industry for orthodontics" (said at 0:47:50)

Experimental animal models and observational human studies support the hypothesis that reduced masticatory loading from soft, processed diets during growth contributes to altered craniofacial development, including narrower maxillary dental arches, crowding, and malocclusion. In experimental non-human primates and other mammals, soft diets consistently produce narrower dental arches and tooth displacement compared to hard, fibrous diets. In pediatric observational studies, higher consumption of soft-textured food is significantly associated with transverse maxillary constriction, high palatal vaults, and posterior crossbite, although the overall etiology of orthodontic malocclusion remains multifactorial (involving genetics, oral breathing habits, and other factors).

1:08:25Andrew Hubermansupportedvery low

Research by Eric Knudsen shows that once learning takes place, neural maps are permanently retained and can be reactivated later in life.

"Here's a beautiful data of a guy named Eric Knudsen, who was actually my next-door neighbor in my lab before he retired at Stanford, showing that you know if once learning takes place, those those maps are forever there. Uh, you can um unveil those maps again later" (said at 1:08:25)

Research from Eric Knudsen's laboratory at Stanford demonstrated that neural connections and map representations established during juvenile learning are structurally preserved even after the behavior returns to baseline. In barn owls raised with prism spectacles that shift visual-auditory alignment, abnormal axonal projections formed in the midbrain auditory pathway persisted long after normal vision was restored and the learned responses were silenced. When re-exposed to prisms in adulthood—a period when de novo map plasticity is typically restricted—owls rapidly reactivated the preserved anatomical circuitry and readapted.

  • supports: Anatomical traces of juvenile learning in the auditory system of adult barn owls. (Nature neuroscience 2005) · cited 97x in the literature
    "Here we show that abnormal anatomical projections acquired during early abnormal sensory experience persist long after normal experience has been restored. These persistent projections are perfectly situated to provide a physical framework for subsequent readaptation in adulthood to the abnormal sensory conditions experienced in early life. Our results show that anatomical changes that support strong learned neural connections early in life can persist even after they are no longer functionally expressed." (abstract, results, passage verified)
    pubmedfull study (doi)
1:09:25Andrew Hubermansupportedvery low

Neurons in the ventromedial hypothalamus mediate rage, sexual activity, and consummatory behaviors such as eating.

"that nucleus, the ventromedial hypothalamus, those neurons are responsible for rage, for unbridled rage. Okay? Those neurons are responsible for unbridled sexual activity. I'm not talking about merged with violence. I'm just saying independent of that. Those are are consummatory behaviors. So, eating, hyperphagia, anorexia, you know." (said at 1:09:25)

The speaker's statement that neurons in the ventromedial hypothalamus (VMH) mediate aggressive behavior (attack/rage), sexual behavior (mating), and feeding/consummatory behaviors (appetite and energy homeostasis) is supported by neurobiological literature. Functional and optogenetic studies in rodent models demonstrate that specific subpopulations of VMH neurons control male and female aggression as well as mating, while broader VMH populations regulate energy balance, appetite, and feeding behaviors. Because these causal mechanisms are demonstrated primarily in rodent models, the overall body of direct functional evidence carries a very low certainty rating according to evidence standards.

1:13:10Andrew Hubermansupportedmoderate

Breaking bad habits involves top-down control where the prefrontal cortex suppresses the activity of hypothalamic and subcortical neurons.

"breaking bad habits involves a lot of top-down control: prefrontal cortex suppressing the activity of these hypothalamic and other subcortical neurons. And how do we know this? Well, if you want to summarize how the prefrontal cortex works, you'd say it's the "shh" structure in the brain." (said at 1:13:10)

Neurobiological literature supports the model of executive control in which the prefrontal cortex (PFC) exerts top-down inhibitory and regulatory control over subcortical and hypothalamic structures to suppress prepotent, impulsive, and habitual behaviors in favor of goal-directed actions.

1:32:45Andrew Hubermansupportedhigh

Physicians washing their hands between conducting autopsies on women who died in childbirth and delivering babies reduced maternal childbirth mortality rates.

"once they started washing their hands between essentially doing autopsy and delivering babies, uh, rates of death in childbirth went down." (said at 1:32:45)

Historical and epidemiological data firmly support the claim. In 1847 at the Vienna General Hospital, Ignaz Semmelweis observed that maternal mortality from puerperal sepsis was significantly higher in Clinic 1 (where doctors and medical students performed autopsies prior to examining patients) than in Clinic 2 (staffed by midwives who did not perform autopsies). Implementing mandatory hand hygiene—washing hands with chlorinated lime solution between conducting autopsies and examining or delivering babies—substantially reduced maternal childbirth mortality rates.

1:34:25Chris Williamson (host)supportedhigh

Rachel Carson's 1962 book Silent Spring warned of environmental damage from pesticides, faced backlash from chemical companies and scientists, and ultimately contributed to the environmental movement and the banning of DDT.

"Rachel Carson in her book 1962, Silent Spring, warned about the environmental damage caused by pesticides. She was mocked by chemical companies and even some scientists, but her work eventually led to the environmental movement and the banning of DDT." (said at 1:34:25)

Historical and ecotoxicological literature confirms the claim. Rachel Carson's 1962 book 'Silent Spring' detailed the ecological hazards and indiscriminate use of synthetic pesticides, notably DDT and other chlorinated hydrocarbons. The publication drew fierce controversy and public resistance from the chemical industry and allied scientists, but it played a pivotal role in catalyzing the modern environmental movement and driving national and international regulatory frameworks that ultimately led to the banning and severe restriction of DDT and other persistent organic pollutants.

1:34:40Chris Williamson (host)supportedhigh

In the 1840s, Ignaz Semmelweis identified that doctors transmitted childbed fever from autopsies to mothers due to lack of handwashing, but his advocacy was ridiculed by peers before germ theory later validated it.

"Ignaz Semmelweis in the 1840s realized that doctors were transmitting childbed fever from autopsies to mothers by not washing their hands. He begged his colleagues to adopt handwashing. They laughed at him. He died in an asylum. Decades later, germ theory proved him right." (said at 1:34:40)

Historical medical literature confirms that in the late 1840s, Hungarian physician Ignaz Semmelweis identified that medical personnel transmitted puerperal (childbed) fever from postmortem examinations to delivering mothers on unwashed hands, and introduced antiseptic handwashing with chlorinated lime solutions. His findings were widely rejected and opposed by contemporary physicians who adhered to miasma and humor-based theories. Semmelweis experienced severe psychiatric and cognitive decline amid this professional ostracization, was committed to an asylum in 1865, and died shortly thereafter from sepsis. His work and hand hygiene principles were later validated and accepted with the establishment of the germ theory of disease.

1:38:50Andrew Hubermansupportedvery low

Physician David Fajgenbaum successfully achieved long-term survival from life-threatening Castleman disease by repurposing existing FDA-approved generic drugs.

"David Fajgenbaum, who's a physician at UPenn um and scientist... he gets this Castleman's disease, which is a cancer-like um disease of the of the lymphatic system. He's told that he's going to die. He He basically was near dead. And then he decided to just start trying all these already approved prescription drugs that nobody thought had anything to do with Castleman's or cancer. And he's alive now 11 years later." (said at 1:38:50)

The published medical literature documents that physician-scientist David Fajgenbaum was diagnosed with idiopathic multicentric Castleman disease (iMCD-TAFRO), experienced recurrent life-threatening multiorgan failure refractory to standard therapies, and identified hyperactive PI3K/Akt/mTOR signaling through proteomic and immunophenotypic analysis of his own and other patients' samples. Initiating treatment with sirolimus (an FDA-approved mTOR inhibitor originally developed for organ transplant rejection) induced durable, multi-year clinical remission in this case series. Because the primary evidence evaluating this self-treatment and drug repurposing is derived from uncontrolled case series and individual clinical reports, the certainty of evidence for general efficacy is very low by study design standards.

1:40:43Andrew Hubermansupportedhigh

Women who undergo breast cancer surgery that utilizes lidocaine as a local anesthetic have a 30% reduced risk of cancer recurrence.

"Turns out that women who have breast cancer surgery that involves lidocaine as a local anesthetic have a 30% less less chance of getting a, you know, of having a recurrence." (said at 1:40:43)

A landmark multicenter randomized controlled trial of 1,600 patients with early breast cancer undergoing primary surgery (Badwe et al., 2023) evaluated presurgical peritumoral infiltration of 0.5% lidocaine. At a median follow-up of 68 months, peritumoral lidocaine led to a significant 26% relative reduction in disease-free survival events (HR 0.74; 95% CI, 0.58 to 0.95), a 27% relative reduction in distant recurrences (HR 0.73; 95% CI, 0.53 to 0.99), a 32% relative reduction in locoregional recurrences (HR 0.68; 95% CI, 0.41 to 1.11), and a 29% relative reduction in overall mortality (HR 0.71; 95% CI, 0.53 to 0.94). The spoken figure of an approximate 30% reduction accurately summarizes the relative risk reduction found in this randomized trial.

1:36:40Andrew Hubermansupportedhigh

Alfred Russel Wallace independently developed the theory of evolution by natural selection in parallel with Charles Darwin.

"everyone thinks of Darwin and natural selection and um but there was another guy, Alfred Russel Wallace, who essentially discovered all of it in parallel um and should have been elected to the Royal Academy and all of this stuff um as well like like Darwin" (said at 1:36:40)

Historical and biological scholarship confirms that Alfred Russel Wallace independently conceived the theory of evolution by natural selection around the same time as Charles Darwin. Wallace drafted his manuscript while working in Indonesia in 1858 and sent it to Darwin, leading to a joint presentation of their papers to the Linnean Society of London in 1858, prior to the publication of Darwin's On the Origin of Species in 1859.

1:36:00Chris Williamson (host)supportedhigh

Galileo Galilei was tried by the Roman Inquisition for promoting heliocentrism, forced to recant, and sentenced to lifelong house arrest.

"Galileo was dragged before the Inquisition, forced to recant under threat of torture, and sentenced to house arrest for the rest of his life." (said at 1:36:00)

Historical records and scholarly analyses confirm that Galileo Galilei was summoned and tried by the Roman Inquisition in 1633 for advocating Copernican heliocentrism following the publication of his 'Dialogue Concerning the Two Chief World Systems'. During the proceedings, Galileo was subjected to formal interrogation regarding his beliefs under threat of torture (territio verbalis), made to formally abjure and recant heliocentrism on June 22, 1633, and sentenced to imprisonment, which was commuted to lifelong house arrest until his death in 1642.

1:41:00Andrew Hubermansupportedhigh

Aspirin is used as a repurposed drug to reduce the risk or progression of colon cancer.

"different uses for aspirin for colon cancer. I mean, you know, and so repurposing old drugs for—" (said at 1:41:00)

Aspirin is widely studied and used as a repurposed agent for colorectal cancer chemoprevention and recurrence prevention. Systematic reviews and meta-analyses of randomized controlled trials demonstrate that aspirin significantly reduces the recurrence of colorectal adenomas and lowers colorectal cancer-related mortality.

1:42:00Andrew Hubermansupportedmoderate

Animal protein sources offer a superior protein-to-calorie ratio compared to plant foods like peanut butter.

"Animal protein is clearly superior as a as a pro quality protein to calorie ratio, right? You give me an 8 oz piece of steak, or you have to eat half a jar of peanut butter, which is not protein. It's a bunch of fat with a little bit of protein in it." (said at 1:42:00)

Nutritional science and established food composition data support that animal protein sources typically provide a higher protein-to-calorie ratio and higher protein quality (digestibility and essential amino acid profile, including leucine) than whole plant foods like peanut butter, which derive the vast majority of their caloric content from fats. Reviews evaluating plant- versus animal-based protein sources demonstrate that whole-food plant sources generally have lower essential amino acid density and lower anabolic efficiency per calorie compared to animal protein sources.

2:09:01Andrew Hubermansupportedhigh

Creatine supplementation causes individuals to gain approximately three pounds of body weight in water weight.

"despite the fact you're probably going to gain, you know, three pounds of of weight... Water. Water weight." (said at 2:09:01)

Randomized controlled trials and consensus reviews consistently demonstrate that creatine supplementation (particularly during initial loading or short-term protocols) leads to an acute increase in total body weight of approximately 1 to 2 kg (around 2 to 4.4 pounds, averaging roughly 3 pounds). This initial weight gain is primarily driven by cellular water retention and increases in total body water associated with elevated intramuscular creatine concentrations, without changes in body fat mass.

2:09:40Chris Williamson (host)supportedmoderate

According to the environmental security hypothesis, hungry men prefer heavier women, whereas satiated men prefer thinner women.

"the original study was done on students that were in halls of residence and they were eating at um uh you like uh dinnertime together where it would be provided by the halls of residence and they showed men images of women of varying sizes uh before they ate and after they ate. multiple iterations all over the place. Before men ate, they preferred the bigger women. After men ate, they preferred the thinner women." (said at 2:09:40)

Published experimental psychology studies evaluating the environmental security hypothesis and resource scarcity models demonstrate this effect. In classic quasi-experimental designs testing college students entering (hungry) or exiting (satiated) campus dining halls, hungry male participants consistently preferred female figures with higher body weight and rated heavier figures as more attractive compared to satiated men.

2:13:38Andrew Hubermansupportedmoderate

Low-level hearing loss is strongly correlated with an increased risk of dementia.

"First of all, hearing loss low-level hearing loss is associated with dementia... partial hearing loss strongly correlated with with dementia." (said at 2:13:38)

Extensive prospective cohort evidence and systematic reviews confirm that hearing loss, including mild (low-level) hearing impairment, is consistently associated with an increased risk of incident dementia. In large meta-analyses of prospective cohort studies, adult-onset hearing impairment is associated with a 30% to 35% increased risk of all-cause dementia (hazard ratios typically between 1.30 and 1.35), with risk increasing in a dose-dependent fashion by approximately 16% for every 10-decibel worsening in hearing ability. Cohort data specifically evaluating mild impairment also demonstrate a statistically significant increase in dementia risk (HR approximately 1.52).

2:16:08Andrew Hubermansupportedhigh

Moderate alcohol consumption increases cancer risk and disrupts sleep architecture and the gut microbiome.

"Moderate drinking is bad for you in terms of elevating cancer risk, certainly disrupting sleep and microbiome and a bunch of other things that aren't good." (said at 2:16:08)

The speaker's statement accurately reflects the published scientific consensus across all three mentioned areas. Systematic reviews and meta-analyses demonstrate that light-to-moderate alcohol consumption increases the risk of multiple cancers (notably breast, colorectal, and esophageal cancers) in a dose-dependent manner. Experimental and meta-analytic evidence shows that even low-to-moderate alcohol doses (around 1–2 standard drinks) alter sleep architecture, particularly by delaying and suppressing REM sleep. Furthermore, alcohol intake is well documented to induce gut microbial dysbiosis, impairing intestinal barrier function and microbial metabolic pathways.

2:20:59Andrew Hubermansupportedmoderate

Late-day exercise induces a cortisol elevation that suppresses morning cortisol levels via negative feedback.

"if you exercise late in the late in the day and then the next morning you're like, 'I'm feeling sluggish. Like, is there something?' No, actually, you had a cortisol bump last night. It's a negative feedback loop. Your cortisol is naturally suppressed." (said at 2:20:59)

Experimental research supports the finding that vigorous late-day exercise increases cortisol levels acutely and subsequently suppresses morning cortisol concentrations and the cortisol awakening response (CAR). In a randomized crossover trial evaluating the effect of acute late-evening exercise (at 18:00 h) on the CAR the next morning (PMID: 36629945), vigorous exercise induced a 477.3% increase in circulating cortisol, which was followed by significantly reduced serum and salivary cortisol concentrations upon waking the following morning compared to a resting control condition. Although the blunting is consistent with delayed hypothalamic-pituitary-adrenal (HPA) axis negative feedback, researchers note that the precise physiological mechanisms remain under investigation.

  • supports: The effect of acute exercise on the cortisol awakening response. (European journal of applied physiology 2023) · cited 12x in the literature
    "Participants demonstrated an average exercise-induced increase in circulating cortisol of 477.3%, with actual mean (SD) heart rate relative to maximum of 87.04% (6.14%). Model results demonstrated a negative effect for exercise condition when modeling the serum and salivary cortisol responses to awakening via a quadratic growth model (serum, β Condition = - 42.26 [95% CI - 64.52 to - 20.01], p < 0.001; saliva, β Condition = - 11.55 [95% CI - 15.52 to - 7.57], p < 0.001). These results suggest that cortisol concentrations in saliva and blood are significantly lower the morning following a prior evening exercise session." (abstract, results, passage verified)
    pubmedfull study (doi)
2:22:30Andrew Hubermansupportedmoderate

A clinical study by Justin Sonnenburg and Christopher Gardner found that eating low-sugar fermented foods consistently reduced inflammatory markers and supported the microbiome, whereas high-fiber intake increased inflammation in half of participants.

"Justin Sonnenburg and Christopher Gardner ran a study looking at low-sugar fermented foods versus fiber effect on the gut microbiome. The outcome was very clear. Eating low-sugar fermented foods decreases the so-called uh inflamm—they call it as opposed to genome, etc. Proteome. Okay. So reduces inflammation bodywide... The fiber group was divided. Some people who intentionally ingested more fiber had reduced so-called inflammatory markers, inflammation, and they looked at a lot of markers. The other half had greatly increased inflammation." (said at 2:22:30)

A 2021 randomized prospective trial led by Christopher Gardner and Justin Sonnenburg (Wastyk et al., Cell, PMID 34256014) evaluated the effects of a high-fermented-food diet versus a high-fiber diet over 17 weeks in 36 healthy adults (n=18 per arm). The study found that fermented foods increased gut microbiota diversity and decreased 19 circulating inflammatory proteins. In contrast, the high-fiber diet led to divergent immune trajectories: participants with low baseline microbiota diversity exhibited increased inflammation, whereas those with higher baseline diversity showed stable or reduced inflammatory markers.

2:25:30Andrew Hubermansupportedvery low

High doses of supplemental melatonin suppress the hypothalamic-pituitary-gonadal axis and can delay puberty in animal studies.

"there are amazing animal data showing that it can suppress the the hypothalamic-gonadal axis... Doesn't it delay puberty in adolescents? Yes." (said at 2:25:30)

Animal models (rodents and seasonal breeding mammals) demonstrate that exogenous melatonin administration can suppress the hypothalamic-pituitary-gonadal (HPG) axis and delay the onset of puberty, as indicated by delayed vaginal opening, decreased gonadotropin-releasing hormone (GnRH) and follicle-stimulating hormone (FSH) secretion, and arrested gonadal development. However, evidence remains limited to preclinical animal models, warranting very low certainty when extrapolating these physiological effects to human adolescents.

2:27:54Andrew Hubermansupportedhigh

Cellular mitochondria originated as bacterial endosymbionts that integrated into eukaryotic cells and retain their own genome.

"the mitochondria were essentially got in They're back Originated as bacteria that got into eukaryotic cells... They have their own little genome. Yeah. They were initially not part of us, some distant version of us." (said at 2:27:54)

The speaker's statement accurately reflects the well-established endosymbiotic theory of mitochondrial evolution. Extensive phylogenetic and comparative genomic evidence demonstrates that mitochondria originated from an ancestral bacterial endosymbiont (related to the Alphaproteobacteria lineage) that was engulfed by an ancestral host cell, a fundamental event in the origin and evolution of eukaryotic cells. Mitochondria retain their own distinct circular or linear double-stranded DNA genome (mtDNA) encoding ribosomal RNAs, transfer RNAs, and essential subunits of the mitochondrial respiratory chain.

2:28:06Chris Williamson (host)supportedhigh

Mitochondria and mitochondrial DNA are inherited exclusively through maternal lineage in humans.

"Do you know how you inherit mitochondria? Through through mom. Yeah." (said at 2:28:06)

In humans and other animals, mitochondria and mitochondrial DNA (mtDNA) are inherited almost exclusively through the maternal lineage. Paternal mtDNA is systematically eliminated through targeted degradation mechanisms, including pre-fertilization mtDNA reduction in sperm and post-fertilization degradation (such as autophagy and the ubiquitin-proteasome system) in the oocyte. While extremely rare instances of paternal mtDNA leakage have been debated in specialized research, strict maternal transmission remains the established rule of human genetics and forensic biology.

4:09:46Andrew Hubermansupportedlow

Melatonin is present in cells throughout the body where its production is not suppressed by light and functions as an antioxidant.

"And and it's also true that there's melatonin in all the cells of your body that are not light that are not suppressed by light, but rather stimulated by light, acts as an antioxidant." (said at 4:09:46)

Extrapineal melatonin is widely synthesized across cells throughout the body, predominantly within mitochondria, comprising the vast majority of the body's total melatonin. Unlike pineal-derived melatonin, which follows a circadian rhythm and is suppressed by ocular light exposure, extrapineal melatonin synthesis is non-circadian, not photoperiod-suppressed, and is not released into systemic circulation. Instead, it functions locally as a potent direct free-radical scavenger and indirect antioxidant to maintain cellular redox homeostasis and protect mitochondrial function.

4:10:36Andrew Hubermansupportedmoderate

Red and near-infrared wavelengths of light penetrate bodily tissue and support mitochondrial health.

"it's clear that long-wavelength light, red light from sunlight, infrared, near-infrared light, is beneficial for us, right? It's low energy, but it can pass into our body. It does support mitochondrial health. It charges the mitochondria." (said at 4:10:36)

Red and near-infrared (NIR) light wavelengths (typically 600–1100 nm, within the 'optical window' of biological tissue) penetrate bodily tissues. The primary established mechanism of photobiomodulation (PBM) involves photon absorption by mitochondrial chromophores, particularly cytochrome c oxidase (complex IV of the electron transport chain). This absorption stimulates electron transport, enhances mitochondrial membrane potential (proton-motive force), increases ATP synthesis ('charging' the mitochondria), and regulates signaling cascades and mitochondrial biogenesis.

2:32:11Andrew Hubermansupportedhigh

Mitochondrial replacement therapy (three-parent IVF) has been approved in England to prevent the transmission of mitochondrial diseases.

"there's something now happening in England. Okay, this has been approved for mitochondrial diseases. So there are people who have mitochondrial diseases and they want to have children, right? And so they you know they don't want to pass along these mitochondrial diseases... it's actually been solved that you can do three-parent IVF to bypass." (said at 2:32:11)

Mitochondrial replacement therapy (also referred to as mitochondrial donation or colloquially 'three-parent IVF') was legally approved in the United Kingdom in 2015 through the Human Fertilisation and Embryology (Mitochondrial Donation) Regulations 2015. The regulations allow techniques such as maternal spindle transfer (MST) and pronuclear transfer (PNT) to prevent the transmission of severe, maternally inherited mitochondrial DNA diseases to offspring.

2:43:42Andrew Hubermansupportedmoderate

The phantom smell of burning toast is a clinical warning sign of temporal lobe seizures.

"normally when somebody gets the sort of phantom smell of burning toast, we worry about temporal lobe seizures." (said at 2:43:42)

Olfactory hallucinations and auras (frequently perceived as burning, foul, or chemical odors, colloquially referenced as burning toast) are recognized clinical manifestations and localizing warning signs of focal epilepsy originating in the mesial temporal lobe and associated olfactory structures (including the amygdala, uncus, and piriform cortex). Published neuroimaging and clinical studies confirm that the onset of transient, phantom olfactory sensations strongly points clinicians toward evaluating for temporal lobe seizures and related structural etiologies.

2:46:15Andrew Hubermansupportedvery low

Physician-scientist David Fajgenbaum successfully placed his own Castleman disease into long-term remission using repurposed FDA-approved medications and founded Every Cure to find new uses for existing drugs.

"David Fajgenbaum, who cured his own Castleman disease through an intelligent approach of taking these already approved drugs to treat Castleman's. I mean, he cured himself. He's alive 11 years now. He's got kids, he's married with kids. He was going to die like dead. But he has this um not-for-profit, Every Cure, where they use AI and and hardcore scientific methods basically... to try and decode different diseases and and try different existing drugs to uh to cure them." (said at 2:46:15)

Published case and translational research records confirm that physician-scientist David Fajgenbaum identified PI3K/Akt/mTOR pathway activation in his own and other patients' interleukin-6-refractory idiopathic multicentric Castleman disease (iMCD). He initiated treatment with the repurposed FDA-approved mTOR inhibitor sirolimus, which achieved sustained long-term remission. Fajgenbaum subsequently co-founded the non-profit organization Every Cure to computationally identify and test repurposed existing drugs for other diseases. Because clinical evidence from single-case reports and small case series is uncontrolled, the certainty of evidence for broad clinical efficacy is very low.

2:34:16Andrew Hubermansupportedhigh

Mitochondrial replacement therapy (three-parent IVF) is not legally permitted in the United States.

"There were people in the United States traveling there. It's not legal here." (said at 2:34:16)

Mitochondrial replacement therapy (MRT) is not permitted in the United States due to federal regulatory bans. Congress attached a spending rider prohibiting the U.S. Food and Drug Administration (FDA) from reviewing or acknowledging clinical submissions for research or therapies involving heritable genetic modifications of human embryos, effectively banning the practice in the U.S. and leading patients to seek treatment internationally.

2

Corroborated by web sources

1:03:30Andrew Hubermancorroborated (web)

Slot machines previously accounted for 10% to 20% of total casino income, but now account for approximately 80%.

"some years ago slot machines were like a small fraction of the total casino income, maybe like 10, 20%. Now it's 80%." (said at 1:03:30)

No published record matching the claim that slot machines previously accounted for 10% to 20% of total casino income but now account for approximately 80% was located; this does not prove the claim false.

corroborated by web sources

Historical industry data and gaming research confirm that slot machines previously contributed only 10% to 20% of casino gambling income before rising to generate roughly 70% to 85% of gaming revenue in most jurisdictions.

forbes.comunlv.edutheworld.org

1:36:36Andrew Hubermancorroborated (web)

The glymphatic system was discovered years earlier by a female scientist at the University of Maryland whose findings were initially rejected after a larger scientific group failed to replicate them due to a methodological error.

"the glymphatic system was discovered many years earlier by a woman at NIH. Um, oh, excuse me, at University of Maryland. Um, a larger, more powerful scientific group tried to repeat the experiments, made a methodological flaw, couldn't repeat it. Everyone believed them. There's no lymphatic system in the brain." (said at 1:36:36)

No published record matching the claim that the glymphatic system was originally discovered by a female researcher at the University of Maryland and subsequently dismissed due to a flawed replication attempt by another group was located; this does not prove the claim false.

corroborated by web sources

In the 1980s, Patricia Grady at the University of Maryland observed perivascular fluid transport in the brain, prefiguring the discovery of the glymphatic system. Her findings were initially dismissed after other research groups failed to replicate the results due to methodological differences that disrupted intracranial pressure.

nih.govsubstack.com

11

No source found (not proven false)

0:11:13Andrew Hubermanunverifiedvery low

A PNAS study found that sleeping in a room with 100 lux of overhead light abnormally elevates morning glucose levels.

"There's a beautiful study published in Proceedings of the National Academy of Sciences that showed that people who sleep in a room with an overhead light of 100 lux, which is extremely dim, show abnormally elevated morning glucose levels." (said at 0:11:13)

No published record matching the claim that a PNAS study found sleeping in a room with 100 lux of overhead light abnormally elevates morning glucose levels was located; this does not prove the claim false.

0:18:38Andrew Hubermanunverifiedvery low

Tart cherry consumption increases apigenin levels.

"Now, I would add to that um saffron, um tart cherry, we know can increase apigenin, apigenin and chamomile extract." (said at 0:18:38)

No published record matching the claim that tart cherry consumption increases apigenin levels was located; this does not prove the claim false.

0:27:31Andrew Hubermanunverifiedvery low

Low-dose lithium (1 mg, such as lithium orotate) promotes sleep onset and increases deep sleep.

"There's some interesting data, although people should talk to their doctor, about taking very low-dose 1 milligram lithium, I think it's the orotate form, in order to encourage the ability to fall asleep and get more deep sleep." (said at 0:27:31)

No published record matching the claim that low-dose lithium (1 mg, such as lithium orotate) promotes sleep onset or increases deep sleep was located; this does not prove the claim false.

0:34:36Andrew Hubermanunverifiedvery low

Looking upward activates the autonomic nervous system to increase alertness, whereas looking downward and lowering the eyelids engages parasympathetic circuits that promote sleepiness.

"When you look up, it's essentially activating the arm of your autonomic nervous system which makes you more alert. It's wild. And eyelids open. It's really interesting. And when you look down and bring your eyelids down, you're actually pedaling on the circuits that promote sleepiness or at least that are more parasympathetic." (said at 0:34:36)

No published record matching the claim that upward gaze directly activates the sympathetic arm of the autonomic nervous system to increase alertness, or that downward gaze and lowering the eyelids selectively engages parasympathetic circuits to promote sleepiness, was located; this does not prove the claim false.

0:37:38Andrew Hubermanunverifiedvery low

Superficial lymphatic vessels run so close to the skin surface that excessive massage pressure collapses and occludes them.

"It feels like nothing. But the lymphatic vessels run so superficially that if you press on them too hard, you actually cinch them off." (said at 0:37:38)

No published record matching the claim that excessive massage pressure collapses and occludes superficial lymphatic vessels was located; this does not prove the claim false.

0:45:00Andrew Hubermanunverifiedvery low

Puffiness and bags under the eyes following acute sleep deprivation are caused by the accumulation of lymphatic fluid.

"The bags under people's eyes, that's buildup of lymph, okay? It's, you know, a couple hours later, that's what that is. It's buildup of lymph" (said at 0:45:00)

No published record matching the claim that under-eye bags or puffiness following sleep deprivation are caused by the accumulation of lymphatic fluid was located; this does not prove the claim false.

0:45:50Andrew Hubermanunverifiedvery low

Sleep deprivation causes an observable change in the color around the iris due to the accumulation of lymph in the anterior chamber of the eye.

"there's actually a change in color of the eyes that has to do with the accumulation of lymph in the anterior chamber of the eye." (said at 0:45:50)

No published record matching the claim that sleep deprivation causes an observable change in eye color due to lymph accumulation in the anterior chamber of the eye was located; this does not prove the claim false.

1:01:15Andrew Hubermanunverifiedvery low

In China, experiments have been conducted where children stare at a focal point on a wall for several minutes before starting their work to improve focus.

"Now, in China, they're doing some very interesting experiments of having kids stare literally at a at a focal point on the wall for a number of minutes before beginning their work." (said at 1:01:15)

No published record matching experiments in China where children stare at a focal point on a wall before schoolwork to improve focus was located; this does not prove the claim false.

2:18:15Chris Williamson (host)unverifiedvery low

Forward locomotion combined with lateral eye movements on a walk significantly downregulates anxiety.

"a locomotion with lateral eye movement on a morning walk downregulates anxiety big time. And not if you're looking at your phone." (said at 2:18:15)

No published record matching the claim that forward locomotion combined with lateral eye movements during a walk downregulates anxiety was located; this does not prove the claim false.

2:44:16Andrew Hubermanunverifiedvery low

Creatine is administered clinically following transient ischemic attacks (TIAs) for neuroprotection.

"They're giving people creatine after TIAs now. It doesn't surprise me, neuroprotective." (said at 2:44:16)

No published record matching the claim that creatine is administered clinically following transient ischemic attacks (TIAs) for neuroprotection was located; this does not prove the claim false.

2:49:23Andrew Hubermanunverifiedvery low

Exposure to long-wavelength light can mitigate the cellular toxicity and damage caused by blue light.

"long-wavelength light can really offset some of the toxicity of of blue light, but it's not just about sleep." (said at 2:49:23)

No published record matching the claim that exposure to long-wavelength light can mitigate or offset cellular toxicity and damage caused by blue light was located; this does not prove the claim false.

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.