HoldsUp

Chris Williamson · 2024-09-09 · Andrew Huberman, Chris Williamson (host)

Why You’re Tired, Unmotivated, and Unfocused - Dr. Andrew Huberman (4K)

60 claims checked against research: 6 contradicted 3 overstated 6 needing context 34 supported 2 corroborated online 9 unverified

6

Contradicted by research

0:17:26Andrew Hubermancontradictedhigh

Rapid eye movement (REM) sleep has been used as a clinical treatment for depression.

"rapid eye movement sleep has also been used as a clinical treatment for depression, right?" (said at 0:17:26)

The speaker claimed that rapid eye movement (REM) sleep has been used as a clinical treatment for depression. In clinical psychiatry and sleep research, it is REM sleep deprivation (or REM sleep suppression), rather than REM sleep itself, that has been studied and utilized as a therapeutic intervention. Randomized clinical trials showed that selectively preventing patients from entering REM sleep (or total sleep deprivation) produced rapid antidepressant responses, and many clinical antidepressant medications function by suppressing REM sleep. Asserting that REM sleep itself is the therapeutic agent inverts the actual clinical intervention.

1:07:39Andrew Hubermancontradictedhigh

When alerted or triggered, locus coeruleus neurons disperse epinephrine/adrenaline across the brain, and adrenals release adrenaline in parallel within hundreds of milliseconds.

"that structure of neurons, that cluster in the in the brainstem called the locus coeruleus—let's just stay with, you know, broad nomenclature—has there's clusters of neurons that do many different things there, but some of them provide, you know, these wire-like axonal inputs, as we call them, in a kind of sprinkler fashion to the brain. And when there's something that alerts us that we need, you know, it's triggering to us, if you will, it just... sprinklers the brain with epinephrine, adrenaline, and boom, the brain wakes up. And then in parallel, your adrenals release adrenaline, and within, you know, a couple hundred milliseconds, you're up" (said at 1:07:39)

The speaker incorrectly identifies epinephrine (adrenaline) as the neurotransmitter released by the locus coeruleus throughout the brain. The primary neurotransmitter synthesized and released by locus coeruleus neurons across diffuse cerebral projections is norepinephrine (noradrenaline), not epinephrine. Epinephrine in the central nervous system is produced by distinct adrenergic cell groups in the medulla, while peripheral epinephrine is secreted as a hormone into the bloodstream by the adrenal medulla during stress, operating on a hormonal timescale rather than a millisecond neurotransmitter release mechanism.

1:31:14Andrew Hubermancontradictedmoderate

Some caterpillar species have evolved poisons that do not kill predatory birds, allowing birds to survive and feed the caterpillars to their offspring, which then form a permanent memory to avoid eating those caterpillars.

"Like some of them have adapted different poisons so that the birds that eat them don't die, but literally survive and transmit the discomfort by feeding their young, and then the young are like, "Uh..." and they actually form a permanent memory not to eat those caterpillars." (said at 1:31:14)

Chemical defenses in caterpillars and other aposematic insects evolve to reduce predation through direct unprofitability (such as emesis, foul taste, or mild toxicity) that induces individual avoidance learning or reinforces innate wariness in the foraging predator itself. No published evidence supports the claim that caterpillar toxins evolved to spare adult birds specifically so parents could feed the prey to their nestlings to transmit an avoidance memory across generations. Studies on avian learned avoidance show that individual predators learn directly through their own foraging encounters with defended prey.

2:23:30Andrew Hubermancontradictedhigh

Nicotinamide mononucleotide (NMN) is a precursor to NAD+, and nicotinamide riboside (NR) is a precursor to NMN.

"Remember, NMN is a precursor to NAD; NR is the precursor to NMN, so there's a phosphate group that gets removed." (said at 2:23:30)

The speaker's statement bundles multiple assertions regarding the NAD+ salvage pathway. It is correct that nicotinamide mononucleotide (NMN) is an immediate precursor to NAD+ (via nicotinamide mononucleotide adenylyltransferases) and that nicotinamide riboside (NR) serves as a precursor to NMN. However, the speaker states the chemical mechanism backwards regarding phosphate modification: NR is a nucleoside (nicotinamide attached to ribose) lacking a phosphate, whereas NMN is a nucleotide containing a 5'-phosphate group. Converting NR to NMN requires the addition of a phosphate group (phosphorylation catalyzed by nicotinamide riboside kinases, NRK1/2), not the removal of a phosphate group. (A phosphate is removed only when converting NMN back into NR, such as during extracellular dephosphorylation by CD73).

2:43:45Andrew Hubermancontradictedmoderate

Lacerations must be sutured within 6 hours of injury to avoid wound infection.

"He said, "You have to get in and get it stitched up within 6 hours." ... To avoid infection. To avoid infection. It's the infection that gets in there." (said at 2:43:45)

Modern clinical evidence and systematic reviews do not support a strict 6-hour 'golden period' rule for laceration closure to prevent infection. Infection risk in traumatic lacerations is primarily determined by wound characteristics (such as degree of contamination, wound length/width, and anatomical location, with lower extremities carrying higher risk) and patient factors (such as diabetes), along with adequate irrigation and debridement. Prospective studies and systematic reviews have found no significant difference in infection rates between simple lacerations repaired before versus after 6 to 12 or more hours.

2:36:40Andrew Hubermancontradictedhigh

The human nervous system contains trillions of individual neurons.

"And then you have literally trillions of neurons, nerve cells, that are independent of one another, little spheres that need to connect to one another in immensely precise ways" (said at 2:36:40)

Quantitative stereological and isotropic fractionator studies establish that the adult human brain contains approximately 86 billion neurons (and about an equal number of non-neuronal cells), not trillions. Even accounting for the peripheral and enteric nervous systems, the total number of neurons in the human body remains around 86 to 100 billion. The number that reaches into the trillions is the count of synaptic connections between neurons, rather than the number of neurons themselves.

3

Overstated

0:07:36Andrew Hubermanoverstatedlow

Studies published out of Scandinavia show that Yoga Nidra-type practices can replenish dopamine stores in the basal ganglia.

"There's some beautiful studies already published out of Scandinavia showing that longer Yoga Nidra-type practices, non-sleep deep rest, can replenish dopamine stores in an area of the brain called the basal ganglia, which prepares you for mental and physical action." (said at 0:07:36)

A landmark 2002 PET imaging study from Denmark (Kjaer et al.) evaluated 8 experienced meditation teachers during Yoga Nidra meditation using [11C]-raclopride, which binds to dopamine D2 receptors in the striatum (part of the basal ganglia). The study showed a significant decrease in raclopride binding, reflecting an estimated 65% increase in endogenous dopamine *release* during meditation, which was associated with a reduced readiness for action. However, the study measured acute extracellular dopamine release (receptor displacement), not the replenishment or synthesis of dopamine stores. Furthermore, the evidence is limited to a single small clinical trial in experienced practitioners, not a broad body of studies showing store replenishment.

0:42:50Chris Williamson (host)overstatedmoderate

Sodium plays a critical role in reducing muscle cramps and fatigue while optimizing brain health, regulating appetite, and curbing cravings.

"Sodium plays a critical role in reducing muscle cramps and fatigue while optimizing brain health, regulating appetite, and curbing cravings." (said at 0:42:50)

While sodium is an essential electrolyte necessary for cellular action potentials, nerve conduction, and fluid balance, claiming that sodium plays a critical role in reducing muscle cramps, optimizing brain health, and curbing cravings significantly overstates the evidence. In exercise physiology, extensive research comparing athletes with and without exercise-associated muscle cramps (EAMC) has found no consistent association between serum sodium levels or electrolyte depletion and cramping; modern evidence strongly points toward altered neuromuscular control and muscle fatigue rather than sodium deficits. Furthermore, while sodium depletion triggers physiological salt appetite, dietary sodium does not act as a general appetite suppressant or craving curber—in fact, dietary salt enhances food palatability and often drives increased intake.

2:44:30Andrew Hubermanoverstatedlow

BPC-157 stimulates angiogenesis (the formation of new blood vessels).

"It can cause—it does cause angiogenesis, growth of blood vessels. So if you have a tumor, you could cause angiogenesis of the tumor." (said at 2:44:30)

The speaker claims that BPC-157 causes angiogenesis (growth of new blood vessels) and that taking it if you have a tumor could cause tumor angiogenesis. In vitro and animal studies demonstrate that BPC-157 exhibits pro-angiogenic properties, promoting vascular endothelial cell migration, tube formation, and upregulation of VEGFR2 and VEGF-A expression to facilitate tissue and wound healing. However, the claim that BPC-157 causes tumor angiogenesis is theoretical and unproven in published literature. Review articles note concern over potential tumor angiogenesis risks given its pro-angiogenic pathway activation, but experimental literature on BPC-157 in tumor models suggests modulatory or anti-tumor effects rather than promoting tumor vascularization. Furthermore, human evidence for BPC-157 is extremely sparse, consisting primarily of preclinical animal and cell culture research.

6

Needs context

0:09:13Andrew Hubermanneeds contextmoderate

Cortisol levels begin rising approximately 30 minutes before waking up.

"So about 30 minutes before waking, your cortisol starts to rise. It's part of the mechanism that wakes you up without an alarm clock." (said at 0:09:13)

Cortisol levels do begin to rise during the second half of the night several hours prior to waking as part of the normal endogenously driven circadian rhythm. However, characterizing this specifically as starting "about 30 minutes before waking" mixes up two distinct circadian phenomena: the broad pre-awakening rise in cortisol (which typically begins 4 to 5 hours before waking, following a nocturnal nadir around sleep onset/midnight) and the Cortisol Awakening Response (CAR), which is a rapid, steep spike in cortisol levels occurring 30 to 45 minutes *after* waking up.

0:17:26Andrew Hubermanneeds contextmoderate

Rapid eye movement sleep is critical for removing the emotional charge of previous-day memories and experiences.

"rapid eye movement sleep is critical for removing the emotional load of previous day and previous day memories and experiences." (said at 0:17:26)

The statement reflects the prominent "Sleep to Forget, Sleep to Remember" (SFSR) neurobiological model, which posits that REM sleep depotentiates the emotional tone of memories while preserving their factual content. Experimental neuroimaging and targeted reactivation studies show that REM sleep physiology—specifically adrenergic suppression paired with amygdala-hippocampal reactivation—is associated with decreased next-day amygdala reactivity and attenuated subjective arousal to emotional stimuli. However, systematic reviews and meta-analyses note that empirical findings across human behavioral and psychophysiological studies remain mixed, with some paradigms showing attenuation, maintenance, or even enhancement of emotional reactivity across sleep intervals.

0:37:38Andrew Hubermanneeds contextmoderate

Adrenaline and epinephrine released from the adrenal glands and the locus coeruleus form the biological basis of flashbulb memories and trigger memory consolidation.

"By the way, sorry, I didn't mean to interrupt, but you know that the origin of flashbulb memory is adrenaline. You know, it's adrenaline released from the adrenals and in the locus coeruleus, sort of a quote-unquote alertness center, although my neuroscience colleagues are going to be like, "There he goes calling brain structures by their function." But, you know, it releases epinephrine into the brain in kind of a sprinkling fashion." (said at 0:37:38)

The speaker accurately captures the broad neurobiological mechanism by which emotional arousal and stress hormones enhance memory consolidation (frequently studied in relation to emotionally salient and flashbulb-like memories). However, the statement contains a neurochemical imprecision: the locus coeruleus is the primary central source of norepinephrine (noradrenaline), not epinephrine (adrenaline). Epinephrine released peripherally from the adrenal medulla does not readily cross the blood-brain barrier; instead, it signals via the vagus nerve to activate central noradrenergic pathways, including the locus coeruleus, which then projects diffusely throughout the brain (including the basolateral amygdala and hippocampus) to modulate synaptic plasticity and long-term memory consolidation.

1:00:56Andrew Hubermanneeds contexthigh

Ketamine is an FDA-approved drug used to dissociate emotions in therapeutic contexts.

"drugs like ketamine, you know, FDA-approved drug for dissociating your emotions while in the presence of" (said at 1:00:56)

Ketamine is an FDA-approved drug, but its FDA approval is specifically as a general anesthetic (and its S-enantiomer, esketamine, is FDA-approved for treatment-resistant depression). While ketamine produces dissociative effects and is widely used off-label in psychiatric and psychotherapeutic contexts (ketamine-assisted psychotherapy), the FDA has not approved ketamine specifically for 'dissociating emotions' or as an adjunct to psychotherapy.

1:01:20Andrew Hubermanneeds contexthigh

Clinical trials showed up to 67% PTSD remission or significant reduction from two sessions of MDMA with a qualified therapist in a clinical setting.

"very impressive clinical trials showing up to 67% even remission of PTSD or significant reduction in PTSD from people that did two sessions of MDMA with a qualified therapist in a clinical setting." (said at 1:01:20)

Phase 3 randomized controlled trials of MDMA-assisted therapy for post-traumatic stress disorder (PTSD) demonstrate robust efficacy in reducing PTSD symptoms compared to therapy with placebo. In the pivotal Phase 3 trial (Mitchell et al., 2021), 67% of participants who received MDMA-assisted therapy no longer met the diagnostic criteria for PTSD at the study endpoint (compared to 32% in the placebo group). However, the standard clinical trial protocol utilized three experimental MDMA sessions (alongside preparatory and integrative therapy sessions), rather than two sessions.

2:39:00Andrew Hubermanneeds contextmoderate

Most neuroplasticity occurring after birth is driven by the selective removal and pruning of connections rather than the formation of new connections.

"and most of the wiring that occurs after we're born, the so-called neuroplasticity, is a selective removal of connections as opposed to the formation of new connections." (said at 2:39:00)

During neural development, brain connectivity is initially established through an overproduction of synapses, followed by widespread activity-dependent selective elimination (pruning) of redundant connections through childhood and adolescence. However, substantial de novo synaptogenesis continues to occur after birth—with peak synaptic density in the human cerebral cortex reached between 3 months (auditory cortex) and over 15 months (prefrontal cortex) postnatally before net elimination predominates. Furthermore, adult neuroplasticity relies on a dynamic balance of new synapse formation, pruning, and functional synaptic strengthening (such as long-term potentiation), rather than being driven solely or overwhelmingly by synapse removal.

34

Supported by research

0:00:15Andrew Hubermansupportedmoderate

Adenosine accumulates in the brain and body relative to the number of hours spent awake.

"Adenosine is an incredibly interesting molecule. It exists in the brain and body. It accumulates with the number of hours that you're awake, so the longer you're awake, the more adenosine accumulates." (said at 0:00:15)

The claim accurately reflects the established homeostatic model of sleep drive, in which prolonged wakefulness and metabolic activity lead to extracellular adenosine accumulation, notably in key sleep-regulatory regions such as the basal forebrain and parts of the cortex. However, experimental data from microdialysis studies indicate that this accumulation is region-specific rather than a uniform increase throughout all brain regions or peripheral tissues.

  • context: Extracellular adenosine in the human brain during sleep and sleep deprivation: an in vivo … (Sleep 2006) · cited 42x in the literature
    "Our observations, along with those in animal studies, indicate that the role of extracellular adenosine in regulating sleep pressure is not a global brain phenomenon but is likely limited to specific basal forebrain areas." (abstract, conclusions, passage verified)
    pubmedfull study (doi)
  • supports: Adenosine, energy metabolism and sleep homeostasis. (Sleep medicine reviews 2011) · cited 320x in the literature
    "In the central nervous system (CNS) an increase in neuronal activity enhances energy consumption as well as extracellular adenosine concentrations. In most brain areas high extracellular adenosine concentrations, through A1 adenosine receptors, decrease neuronal activity and thus the need for energy... We have identified a relatively specific area, the basal forebrain (BF), which appears to be central in the regulation/execution of recovery sleep after sleep deprivation (SD), or prolonged wakefulness. Adenosine concentration increases in this area during SD, and this increase induces sleep while prevention of the increase during SD abolishes recovery sleep." (abstract, results, passage verified)
    pubmedfull study (doi)
0:01:04Andrew Hubermansupportedhigh

Caffeine works by blocking adenosine receptors in the body and brain.

"caffeine... effectively works by blocking the adenosine receptor." (said at 0:01:04)

At dietary and physiologically relevant doses, caffeine acts primarily as a competitive nonselective antagonist of adenosine receptors (most notably A1 and A2A subtypes) in both the central nervous system and peripheral tissues. By binding to these receptors, caffeine blocks endogenous adenosine from exerting its inhibitory and sedative signals, thereby promoting wakefulness, vigilance, and psychomotor arousal.

0:02:04Andrew Hubermansupportedmoderate

Adenosine is cleared from the brain and body during sleep.

"when we go to sleep at night, adenosine is cleared from our system." (said at 0:02:04)

Extracellular adenosine acts as a key homeostatic regulator of sleep pressure. Adenosine concentrations progressively increase in brain regions such as the basal forebrain and cortex during sustained wakefulness and are subsequently metabolized and cleared back toward baseline levels during sleep.

0:10:44Andrew Hubermansupportedhigh

Viewing bright light suppresses melatonin levels.

"When you view bright light at night or during the day, and especially in the morning, it quashes those melatonin levels." (said at 0:10:44)

Controlled human experimental trials demonstrate that ocular light exposure exerts acute, dose-dependent suppressive effects on plasma melatonin concentrations.

0:14:50Chris Williamson (host)supportedmoderate

Specific genetic mutations allow certain individuals to function naturally on only 3 to 5 hours of sleep per night.

"There's—what is it? It's a very small number of people, but there is a genetic mutation that allows certain cohorts to exist on between sort of 3 and 5 hours of sleep, and that's just where they're at." (said at 0:14:50)

Genetic research has identified rare mutations associated with the familial natural short sleep (FNSS) trait. Individuals carrying specific rare variants—such as in DEC2 (BHLHE41), ADRB1, NPSR1, and GRM1—maintain lifelong short sleep durations (typically 4 to 6 hours, and in some individuals down to 3 to 5 hours) without exhibiting the cognitive deficits or adverse health consequences typically caused by sleep deprivation.

0:29:13Andrew Hubermansupportedhigh

The human intrinsic circadian clock generates an intrinsic rhythm of approximately 24.2 or 24.3 hours.

"Your circadian clock, intrinsic to you, generates a 24.2 or a 24.3-hour rhythm—it's not perfectly 24 hours." (said at 0:29:13)

Rigorous human forced-desynchrony and constant-routine laboratory protocols established that the intrinsic period of the human master circadian pacemaker is slightly longer than 24 hours, averaging approximately 24.18 to 24.2 hours across both young and older adults with very tight distribution.

0:11:04Andrew Hubermansupportedhigh

Melatonin is released from the pineal gland.

"melatonin, which is released from the pineal gland, a pea-sized gland sort of deep in the vestiges of your brain." (said at 0:11:04)

Melatonin is a well-established neurohormone synthesized and secreted primarily by the pineal gland in a circadian pattern governed by the suprachiasmatic nucleus, with secretion stimulated by darkness and suppressed by light.

0:24:35Andrew Hubermansupportedhigh

Genetic polymorphisms cause certain individuals to be natural night owls with delayed sleep phases.

"So there are genetic mutations, they call them polymorphisms, that make some people night owls. They feel best psychologically and physically going to sleep at about 1:00, 2:00, or 3:00 a.m. and waking up somewhere around, you know, 10:00, 11:00 a.m. or noon." (said at 0:24:35)

Large-scale genome-wide association studies and monogenic pedigree analyses demonstrate that genetic variations and polymorphisms directly influence chronotype and delayed sleep phases. A landmark GWAS of 697,828 individuals identified 351 genetic loci enriched in circadian regulation pathways that associate with natural morningness versus eveningness and objectively measured sleep timing. Additionally, specific coding variants in core circadian clock genes—such as a dominant mutation in CRY1 that lengthens the period of the circadian molecular oscillator—cause familial delayed sleep phase disorder (DSPD), resulting in substantially delayed sleep-wake schedules.

0:27:38Andrew Hubermansupportedvery low

There is a direct neural pathway from the brainstem to the suprachiasmatic nucleus that entrains the circadian clock in response to exercise.

"In the case of exercise, there's literally a brain stem to circadian clock connection, a big superhighway of neuronal connection that then so-called entrains your circadian clock." (said at 0:27:38)

Preclinical evidence supports the existence of a direct serotonergic neural pathway from the midbrain raphe nuclei in the brainstem to the suprachiasmatic nucleus (SCN) of the hypothalamus that mediates exercise/activity-dependent entrainment of the central circadian clock. In rodent models, selectively lesioning these serotonergic terminals prevented scheduled voluntary wheel running from entraining circadian rhythms without altering baseline physical activity. Because this specific neural mechanism of exercise entrainment has been demonstrated in animal models rather than direct human trials, the certainty of evidence is very low.

0:32:06Andrew Hubermansupportedhigh

Viewing bright light between 4:00 p.m. and 10:00 p.m. causes a phase delay in the circadian clock, making an individual want to wake up later the following morning.

"If you want to become a night person, you do the opposite: you view bright light between the hours of 4:00 p.m. and 10:00 p.m., and then you will phase delay or phase shift in a delayed way your circadian clock, making you want to wake up later the next morning." (said at 0:32:06)

Extensive human photobiology and circadian research has established the phase response curve (PRC) to bright light. Light exposure in the late subjective day and early subjective night (such as between late afternoon and late evening, before the core body temperature minimum) produces phase delays in the human circadian clock, shifting the circadian rhythm of melatonin, body temperature, and the endogenous drive for sleep and wake timing later.

0:33:20Andrew Hubermansupportedmoderate

Intrinsically photosensitive retinal ganglion cells that project to the circadian clock are present in every extant mammalian species.

"Intrinsically photosensitive retinal ganglion cells, the ones that project to the clock and carry all of this thing about circadian entrainment to sunlight, are present, as far as we know, in every extant mammalian species—every mammalian species that's alive today." (said at 0:33:20)

Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin (OPN4) and project via the retinohypothalamic tract to the suprachiasmatic nucleus (the master circadian pacemaker) to drive circadian photoentrainment. Comparative neuroanatomical studies and large-scale genomic analyses across mammalian orders—encompassing diurnal, nocturnal, and naturally blind subterranean species (such as blind mole rats)—demonstrate that melanopsin and the retinohypothalamic pathway mediating circadian entrainment are conserved across extant mammalian lineages.

  • supports: Evolutionary Constraint on Visual and Nonvisual Mammalian Opsins. (Journal of biological rhythms 2021) · cited 52x in the literature
    "Using genomic data from over 400 mammalian species from 22 orders, unique patterns of evolution for each mammalian opsins were identified, including photoisomerases, RGR-opsin (RGR) and peropsin (RRH), as well as atypical opsins, encephalopsin (OPN3), melanopsin (OPN4), and neuropsin (OPN5)... Importantly, all mammalian opsins retain key amino acid residues important for conjugation to retinal-based chromophores, permitting light sensitivity." (abstract, passage verified)
    pubmedfull study (doi)
  • supports: Comparative Neurology of Circadian Photoreception: The Retinohypothalamic Tract (RHT) in S… (Frontiers in neuroscience 2021) · cited 17x in the literature
    "The mammalian eye contains two systems for light perception: an image detecting system constituted primarily of the classical photoreceptors, rods and cones, and a non-image forming system (NIF) constituted of a small group of intrinsically photosensitive retinal ganglion cells driven by melanopsin (mRGCs). The mRGCs receive input from the outer retina and NIF mediates light entrainment of circadian rhythms, masking behavior, light induced inhibition of nocturnal melatonin secretion, pupillary reflex (PLR), and affect the sleep/wake cycle. This review focuses on the mammalian NIF and its anatomy in the eye as well as its neuronal projection to the brain. This pathway is known as the retinohypothalamic tract (RHT)." (abstract, passage verified)
    pubmedfull study (doi)
0:34:00Andrew Hubermansupportedmoderate

Neuroplasticity occurs during sleep, and sleep reduces adenosine levels in the brain.

"Neuroplasticity occurs during sleep, it pushes down adenosine, you know, it takes us through these natural ebbs and cycles of cognition." (said at 0:34:00)

Extensive neurobiological research supports both assertions. Sleep plays a critical role in neuroplasticity, offline memory consolidation, and synaptic homeostasis, during which spontaneous neural activity renormalizes synaptic strength and stabilizes neural circuits. In addition, extracellular adenosine—a somnogenic neuromodulator that accumulates during wakefulness and sleep deprivation (notably in the basal forebrain)—is cleared and restored to baseline levels during recovery sleep.

0:37:56Andrew Hubermansupportedhigh

A review by James McGaugh in the Annual Review of Neuroscience describes a medieval practice where children were given religious tutorials and then thrown into cold water to spike adrenaline and enhance memory retention.

"You know that there's we know, and there's a beautiful review by James McGaugh, one of the leading researchers in memory, about this, that dating back to medieval times, if they wanted kids to remember something, I'm not making this up, in an Annual Review of Neuroscience, it starts off by describing they would take kids, they'd give them a tutorial—typically, it was a religious tutorial back then—then they'd throw them into cold water so you got a spike in adrenaline, and then you'd remember what you had heard prior." (said at 0:37:56)

The claim accurately describes the introductory premise and neurobiological findings reviewed by memory neurobiologist James L. McGaugh. In his influential review in the Annual Review of Neuroscience (2004, 27:1–28), McGaugh begins by describing the historical practice from past centuries of throwing young boys into rivers (or inflicting sudden pain) immediately after witnessing an important event or lesson to ensure they would retain long-term memory of it. McGaugh's review and subsequent papers detail how acute post-learning emotional arousal triggers adrenal stress hormones (epinephrine/adrenaline and glucocorticoids) acting on the basolateral amygdala to enhance memory consolidation.

0:30:16Andrew Hubermansupportedhigh

Exposure to even small amounts of bright artificial light between approximately 9:30 p.m. and 4:00 a.m. suppresses melatonin secretion and impairs sleep quality.

"it requires just a little bit of bright light, even from an artificial source, after the hours of about 9:30 p.m. till 4:00 a.m. to quash your melatonin, make it difficult to sleep, or if you sleep, to make that sleep not as effective." (said at 0:30:16)

Extensive controlled human experimental evidence and systematic reviews confirm that exposure to artificial light during evening and nighttime hours suppresses melatonin secretion, delays circadian timing, increases sleep latency, and impairs sleep quality and alertness. Dose-response studies show that the human circadian system is sensitive to relatively low levels of evening artificial light, with half-maximal melatonin suppression occurring at approximately 25 lux (and as low as 6 lux in sensitive individuals), which is well below typical indoor lighting (100–300 lux). Controlled trials of light-emitting devices before bedtime similarly show delayed sleep onset, acute melatonin suppression, and reduced sleep effectiveness.

1:01:11Andrew Hubermansupportedhigh

MDMA recently failed to receive FDA approval for the treatment of PTSD.

"MDMA, which just recently, day before yesterday, failed to pass approval by the FDA for the treatment of PTSD." (said at 1:01:11)

In 2024, the US Food and Drug Administration (FDA) rejected the New Drug Application (NDA) for MDMA-assisted therapy (submitted by Lykos Therapeutics) for the treatment of post-traumatic stress disorder (PTSD), requesting an additional phase 3 clinical trial due to concerns over study design (such as functional unblinding), safety evaluations, and data integrity.

1:14:22Andrew Hubermansupportedhigh

During rapid eye movement (REM) sleep, skeletal muscle is paralyzed while the brain remains active.

"And if you think about rapid eye movement sleep, which is the most dream-rich sleep, your body is paralyzed and the mind is active." (said at 1:14:22)

Rapid eye movement (REM) sleep—also termed paradoxical sleep—is characterized by wake-like, desynchronized cortical electroencephalogram (EEG) patterns indicating active cerebral processing alongside active motor inhibition (muscle atonia) of somatic skeletal musculature, mediated by descending brainstem and spinal circuits.

1:18:55Andrew Hubermansupportedhigh

Psychologist Erik Erikson posited that human development consists of core psychosocial conflicts worked out at distinct stages from birth until death.

"And the great psychologist Erikson talked about at every stage of life, from birth until death, until one's 80s and 90s, you're working out some core conflicts of agency versus autonomy versus having to do what other people have you do." (said at 1:18:55)

Erik Erikson's landmark framework of psychosocial development posits that individuals progress through a series of developmental stages across the entire lifespan, from birth through old age (80s and 90s). At each stage, individuals encounter a primary psychosocial conflict or crisis—such as Autonomy versus Shame and Doubt in early childhood, or Integrity versus Despair in late adulthood—that must be navigated to foster psychological growth.

1:25:06Andrew Hubermansupportedmoderate

Carrying two copies of a genetic mutation causing adrenal androgen overproduction (such as non-classical congenital adrenal hyperplasia) can cause infertility, whereas heterozygosity (carrying one copy) causes androgen overproduction without causing infertility.

"I'm a heterozygote for a certain genetic mutation: I overproduce androgen from my adrenals. If you have two copies, it can make you infertile; fortunately, I don't, I have one copy, and it doesn't result in any other bodily differences or anything like that." (said at 1:25:06)

Biallelic pathogenic variants in CYP21A2 cause 21-hydroxylase deficiency (classic or non-classic congenital adrenal hyperplasia [CAH]), which leads to adrenal androgen excess that frequently causes subfertility or infertility in women due to chronic anovulation and elevated progesterone levels. In contrast, monoallelic (heterozygous) carriers often exhibit mild adrenal steroidogenic abnormalities, including intermediate elevations in basal or ACTH-stimulated adrenal androgen and precursor levels (such as 17-hydroxyprogesterone), generally without severe phenotypic consequences or frank infertility.

1:40:25Andrew Hubermansupportedhigh

Andrew Huberman's laboratory published two papers, including a clinical trial, in 2023.

"we published two papers including a clinical trial in 2023" (said at 1:40:25)

In 2023, Andrew Huberman's laboratory published two original research articles in Cell Press journals. This included a remote randomized controlled clinical trial evaluating breathwork exercises versus mindfulness meditation (Balban et al., Cell Reports Medicine, NCT05304000) and a basic neuroscience study examining retinal axon regeneration (Tran et al., Cell Reports).

2:21:57Andrew Hubermansupportedhigh

Rapamycin targets mTOR and broadly mimics the biological effects of fasting.

"Rapamycin targets the mTOR, and in some sense mimics fasting." (said at 2:21:57)

Rapamycin is a direct pharmacological inhibitor of the mechanistic target of rapamycin (mTOR), a central nutrient-sensing kinase complex. During fasting or caloric restriction, mTOR signaling is naturally suppressed, leading to downstream biological processes such as autophagy induction, reduced mRNA translation, and metabolic remodeling. Because inhibiting mTOR pharmacologically reproduces key downstream cellular pathways and longevity-associated phenotypes of nutrient deprivation, rapamycin is widely classified and studied as a caloric restriction and fasting mimetic.

2:22:04Andrew Hubermansupportedhigh

Studies across multiple species, including mice, demonstrate that severe caloric restriction significantly extends lifespan.

"Keep in mind that the studies showing extension of life in different species, including mice, show that being fairly dramatically sub-maintenance caloric extends lifespan" (said at 2:22:04)

The claim is supported by extensive laboratory evidence. Caloric restriction (CR) or dietary restriction significantly extends lifespan across multiple diverse model organisms, including yeast, Caenorhabditis elegans, Drosophila, mice, and non-human primates (rhesus monkeys). For example, a 2024 study by Nduhishe et al. evaluating 960 genetically diverse mice demonstrated that 20% and 40% caloric restriction extended lifespan in proportion to the degree of restriction (PMID: 39385029). Similarly, meta-analyses and reviews confirm CR extends lifespan across various taxa (PMID: 23438200, PMID: 12936916), and joint analyses of long-term non-human primate studies demonstrate survival and health benefits in rhesus monkeys (PMID: 28094793).

2:22:26Andrew Hubermansupportedhigh

Severe caloric restriction causes testosterone levels, libido, and fertility to plummet in both men and women.

"I mean, at some point you are sub-caloric enough that testosterone levels plummet in men and women, libido plummets, fertility plummets in men and women." (said at 2:22:26)

Substantial evidence from randomized clinical trials and endocrine literature confirms that severe energy deficit or low energy availability suppresses the hypothalamic-pituitary-gonadal (HPG) axis in both sexes. In controlled clinical trials of energy deficit, total and free testosterone levels significantly decrease in men. Energy deficiency disrupts hypothalamic gonadotropin-releasing hormone (GnRH) pulsatility, diminishing pituitary secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In females, this leads to functional hypothalamic amenorrhea, hypoestrogenism, and anovulatory infertility. In males, it results in hypogonadotropic hypogonadism with suppressed testosterone levels and impaired reproductive function.

2:23:44Andrew Hubermansupportedmoderate

Research indicates that nicotinamide riboside (NR) converts to NAD+ within cells more readily than nicotinamide mononucleotide (NMN).

"and point to the fact that NR has been shown to convert to NAD in cells more readily than NMN." (said at 2:23:44)

Cellular and isotope-tracing studies demonstrate that nicotinamide riboside (NR) is taken up directly into mammalian cells via equilibrative nucleoside transporters (ENTs) to form NAD+, whereas extracellular nicotinamide mononucleotide (NMN)—a phosphorylated nucleotide—generally cannot cross the plasma membrane intact in most cell types. Instead, extracellular NMN must first be dephosphorylated to NR by extracellular enzymes (such as CD73/ecto-5'-nucleotidase) before entering the cell and converting to NAD+, making NR uptake and subsequent intracellular conversion more direct.

2:26:30Andrew Hubermansupportedmoderate

Research from Glen Jeffery's laboratory at University College London demonstrates that morning red light therapy can offset age-related vision decline.

"we have the data from Glen Jeffery's lab showing that red light therapy, especially in the early part of the day, may offset some age-related vision decline." (said at 2:26:30)

Research led by Glen Jeffery at University College London has demonstrated that brief exposure to deep red light (670 nm) can improve age-related declines in photoreceptor function in older adults. In human studies, 670 nm light significantly improved tritan (blue) color contrast sensitivity and rod thresholds in individuals aged 40 and older, with subsequent work highlighting that photobiomodulation of mitochondrial ATP production and visual function is most effective when administered during morning hours.

2:37:55Andrew Hubermansupportedvery low

Netrin and ephrin act as chemoattractants and guidance cues during nervous system wiring.

"And indeed, those chemoattractants exist. They go by the names of things like netrin, which means to guide, or ephrin, etc." (said at 2:37:55)

Netrins and ephrins are well-established guidance cues in neural development. Netrins (derived from the Sanskrit 'netr', meaning 'guide' or 'one who guides') act as bifunctional chemotropic cues (functioning as chemoattractants or chemorepellents depending on receptor expression), while ephrins and their Eph receptors provide critical guidance and positional signaling to direct axonal growth cones during nervous system wiring.

2:47:25Andrew Hubermansupportedmoderate

Taking hCG maintains sperm production when using exogenous testosterone.

"you need to bank sperm if you want kids, you need to take HCG if you want to maintain sperm production, you need to keep dosages low." (said at 2:47:25)

Clinical studies and reviews support the claim that co-administering human chorionic gonadotropin (hCG) alongside exogenous testosterone therapy maintains intratesticular testosterone and preserves spermatogenesis. Exogenous testosterone alone suppresses luteinizing hormone and follicle-stimulating hormone via negative feedback on the hypothalamic-pituitary-gonadal axis, frequently causing severe oligospermia or azoospermia. Concomitant low-dose hCG acts as an LH analog, stimulating Leydig cells to maintain the intratesticular testosterone levels required for continued sperm production.

2:47:57Andrew Hubermansupportedvery low

Animal studies show BPC-157 promotes fibroblast recruitment and tissue repair in models of Achilles tendon rupture and sciatic nerve injury.

"Here's what we know about BPC-157: it's from the animal studies, it seems able to detect injury in some very interesting way and lead to fibroblasts, a certain kind of cell type relevant to tendon, etc. ... It's actual Achilles tendon ruptures in the mice or the rats that they're using, right? ... And sciatic nerve as well." (said at 2:47:57)

Animal and in vitro studies support the claim. In rat models of Achilles tendon transection, administration of BPC-157 significantly promoted tendon fibroblast outgrowth, migration, survival under oxidative stress, collagen formation, and functional/biomechanical recovery. Similarly, in rat models of sciatic nerve transection, BPC-157 accelerated axonal regeneration, improved nerve conduction and functional recovery, and enhanced tissue healing. Because the evidence is derived exclusively from preclinical rodent and in vitro models, the certainty of evidence for translational human clinical efficacy remains very low.

2:59:46Andrew Hubermansupportedhigh

Glaucoma is the second leading cause of blindness in the world, second only to cataracts.

"trying to understand and cure glaucoma, the second leading cause of blindness in the world, second only to cataracts." (said at 2:59:46)

Global epidemiological analyses from the Vision Loss Expert Group and the Global Burden of Disease Study confirm that cataract is the leading cause of blindness globally, and glaucoma is the second leading cause (and the leading cause of irreversible blindness).

2:39:06Andrew Hubermansupportedmoderate

Cerebrolysin is marketed and sold in Europe, but is not approved for sale in the United States.

"Cerebrolysin, which is sold in Europe, but not the US." (said at 2:39:06)

Cerebrolysin (a porcine brain-derived peptide preparation produced primarily in Austria) is authorized and marketed in numerous European and international countries for conditions such as stroke, traumatic brain injury, and dementia, but it is not approved by the U.S. Food and Drug Administration (FDA) for clinical sale or use in the United States.

5:04:24Andrew Hubermansupportedmoderate

Anorexia nervosa has the highest mortality rate of all psychiatric disorders.

"anorexia nervosa, the most deadly of all psychiatric illnesses, period." (said at 5:04:24)

Systematic reviews and meta-analyses of longitudinal cohort studies demonstrate that anorexia nervosa (AN) carries one of the highest premature mortality rates and standardized mortality ratios (SMRs) of any psychiatric disorder. A landmark meta-analysis of 36 studies reported a weighted SMR of 5.86 for anorexia nervosa, significantly higher than for other eating disorders and major psychiatric illnesses, with deaths resulting from both medical complications (such as cardiac failure) and suicide. Subsequent updated meta-analyses continue to confirm pooled SMRs between 5.06 and 5.21 for AN.

5:12:38Andrew Hubermansupportedhigh

Human rod photoreceptors in the retina are capable of detecting a single photon of light.

"one that is the rod system, which is very sensitive, it's the one you use at dusk and at night to sense if there's anything in your environment. It's very sensitive, it can detect one photon, one photon, but it has very poor acuity." (said at 5:12:38)

Physiological and psychophysical research confirms that human rod photoreceptors respond reliably to individual photons of light and that human subjects can report single-photon stimuli significantly above chance levels. Single-cell electrophysiological recordings of primate photoreceptors demonstrate that rod cells generate a distinct, stereotyped electrical signal in response to a single photon. Furthermore, behavioral studies utilizing quantum single-photon light sources have confirmed that humans are capable of perceiving single-photon inputs incident on the eye.

5:13:10Andrew Hubermansupportedhigh

Dogs possess dichromatic vision, possessing two types of cone photoreceptors, unlike trichromatic humans.

"dogs see this probably as kind of a blunted orange or a burnt orange because they are dichromats, not trichromats." (said at 5:13:10)

Electrophysiological and behavioral studies confirm that dogs possess dichromatic color vision based on two classes of cone photoreceptors (short-wavelength-sensitive cones peaking at approximately 429-435 nm and long/medium-wavelength-sensitive cones peaking at approximately 555 nm), unlike the trichromatic visual system of normal humans.

5:20:54Andrew Hubermansupportedmoderate

Creatine monohydrate supplementation does not damage kidney function and supports cognitive performance.

"Turns out doesn't destroy your kidneys, okay. It's also good for cognition, it turns out." (said at 5:20:54)

Systematic reviews and meta-analyses of randomized controlled trials support both assertions. Regarding kidney function, meta-analyses demonstrate that while creatine supplementation can lead to a slight increase in serum creatinine levels (due to increased metabolic turnover of creatine into creatinine), it causes no significant alterations in actual renal filtration markers such as glomerular filtration rate (GFR), estimated GFR (eGFR), or serum urea. Regarding cognitive performance, meta-analyses of randomized trials show that creatine supplementation significantly improves aspects of cognitive function, particularly memory performance, processing speed, and attention, with pronounced benefits observed in older adults and populations experiencing metabolic stress.

5:02:19Andrew Hubermansupportedhigh

The BRAIN Initiative infused over $100 million into brain research when launched during the Obama administration.

"during the Obama administration, there was the BRAIN Initiative. It infused over $100 million into brain research." (said at 5:02:19)

The Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative was officially launched by President Barack Obama on April 2, 2013, with an initial federal investment proposed at approximately $100 million for Fiscal Year 2014 across federal agencies including the National Institutes of Health (NIH), Defense Advanced Research Projects Agency (DARPA), and National Science Foundation (NSF). Funding grew substantially in subsequent fiscal years.

2

Corroborated by web sources

2:30:45Chris Williamson (host)corroborated (web)

Ross Edgley was the first person to complete a continuous swim around the coast of mainland Great Britain.

"Ross Edgley, do you remember Ross? He swam around the UK, was the first man to ever swim around the UK." (said at 2:30:45)

No published scholarly record matching the claim that Ross Edgley was the first person to complete a continuous swim around the coast of Great Britain was located; this does not prove the claim false.

corroborated by web sources

In November 2018, British endurance athlete Ross Edgley completed the 1,780-mile "Great British Swim" in 157 days, becoming the first person to circumnavigate mainland Great Britain by sea without setting foot on land.

youtube.comwikipedia.org

5:02:19Andrew Hubermancorroborated (web)

The BRAIN Initiative's budget was cut by approximately 40% in recent federal funding appropriations.

"Just this last year or so, the BRAIN Initiative was cut, the budget was cut by approximately 40%" (said at 5:02:19)

No published record matching the claim that the NIH BRAIN Initiative's budget was cut by approximately 40% in recent federal funding appropriations was located; this does not prove the claim false.

corroborated by web sources

In the fiscal year 2024 federal spending package, appropriations for the National Institutes of Health's BRAIN Initiative dropped from $680 million in FY 2023 to $402 million, representing an approximate 40% reduction. The decrease was largely driven by scheduled reductions in funding authorized under the 21st Century Cures Act.

nih.govworldhealth.netthetransmitter.org

9

No source found (not proven false)

0:01:04Andrew Hubermanunverifiedvery low

More than 90% of the world's adult population consumes caffeine.

"caffeine, which is consumed by, it's estimated, more than 90% of the world's adult population" (said at 0:01:04)

No published record matching the claim that more than 90% of the world's adult population consumes caffeine was located; this does not prove the claim false.

0:09:43Andrew Hubermanunverifiedvery low

Viewing bright light in the morning induces a nearly 50% increase in the peak height of cortisol.

"When you view bright light... you induce a near 50% increase in the height of that cortisol peak." (said at 0:09:43)

No published record matching the claim that viewing bright light in the morning induces a nearly 50% increase in the peak height of cortisol was located; this does not prove the claim false.

0:30:36Andrew Hubermanunverifiedvery low

Viewing sunlight in the afternoon, even for about 5 minutes, adjusts retinal sensitivity and reduces the melatonin-suppressive effects of bright light at night by approximately 50%.

"and this is a beautiful study published in Scientific Reports in 2022—if you view sunlight in the afternoon, even for 5 minutes or so, could be late afternoon, could be sunset, take off your sunglasses, look in the direction of the sun, so now looking west, you adjust the sensitivity of your retina, the neurons in the back of your eye, such that bright light later at night doesn't have quite as much effect to suppress melatonin. It reduces the melatonin-suppressive effects by about 50%, or offsets those." (said at 0:30:36)

No published record matching the claim of a 2022 Scientific Reports study demonstrating that viewing afternoon sunlight for approximately 5 minutes reduces nighttime melatonin suppression by about 50% was located; this does not prove the claim false.

0:37:10Chris Williamson (host)unverifiedvery low

In controlled experiments, the impact of statistics on beliefs fades by 73% over the course of a day, compared to a 32% fade for stories.

"In controlled experiments, research has documented a pronounced story-statistic gap in memory. The average impact of statistics on beliefs fades by 73% over the course of a day. The impact of a story fades by only 32%. So 73% average impact of statistics on beliefs, 32% on a story." (said at 0:37:10)

No published record matching the claim that the impact of statistics on beliefs fades by 73% over a day compared to 32% for stories was located in the searched biomedical and life sciences literature; this does not prove the claim false.

2:21:44Andrew Hubermanunverifiedvery low

During development, mTOR is expressed at very high levels in nearly all cells of the brain and body, and its expression declines across the lifespan.

"Remember that mTOR, which is expressed at very high levels in essentially all cells of the brain and body during development, declines across the lifespan." (said at 2:21:44)

No published record matching the claim that mTOR expression is present at very high levels in nearly all cells during development and progressively declines across the lifespan was located; this does not prove the claim false.

2:24:05Andrew Hubermanunverifiedvery low

Because NMN was authorized for evaluation as an investigational new drug in clinical trials, the FDA determined it could not be sold as a dietary supplement.

"and then he started a company that is evaluating it as a drug in a clinical trial. Therefore, the FDA said that NMN could not be sold as a supplement." (said at 2:24:05)

No published record matching the claim that the FDA determined nicotinamide mononucleotide (NMN) could not be sold as a dietary supplement due to its authorization for evaluation as an investigational new drug was located; this does not prove the claim false.

2:31:05Chris Williamson (host)unverifiedvery low

Ross Edgley completed the world's longest single-distance nonstop swim, covering 300 miles over more than 50 hours without touching land or sleeping.

"He's just completed the world's longest single-distance nonstop swim. How far? 300 miles. Without touching land, without stopping, without sleeping. It was over 50 hours." (said at 2:31:05)

No published record matching the claim regarding Ross Edgley's 300-mile nonstop swim was located; this does not prove the claim false.

2:38:15Andrew Hubermanunverifiedvery low

The majority of wiring in the nervous system occurs via selective repulsion rather than chemoattraction.

"But far and away, by I would say by an order of magnitude, most wiring in the nervous system occurs by selective repulsion. In other words, by neurons growing out, looking for something to connect to, and chemical labels saying, "Uh-uh, not here. Uh-uh, not here. Nope, not here."" (said at 2:38:15)

No published record matching the quantitative claim that axon guidance or nervous system wiring occurs predominantly—by an order of magnitude or majority—via selective repulsion rather than chemoattraction was located; this does not prove the claim false. Standard axon guidance literature establishes that neural circuit assembly relies on a balanced combination of attractive and repulsive cues (such as Netrins, Semaphorins, Slits, and Ephrins) acting both at long range and short range, rather than a system dominated exponentially by repulsive forces alone.

2:38:55Andrew Hubermanunverifiedvery low

Cortexin accelerates nerve growth through mechanisms relevant to the TrkB pathway.

"Cortexin, things that are relevant to the TrkB pathway and can accelerate nerve growth—not Trk receptors, BDNF, not that pathway, but TrkB." (said at 2:38:55)

No published record matching the claim that Cortexin accelerates nerve growth specifically through mechanisms relevant to the TrkB pathway was located; this does not prove the claim false. Published studies on Cortexin (a bovine brain cortex peptide extract) describe broad neuroprotective, anti-inflammatory, and anti-apoptotic effects (such as modulating caspase-8, caspase-3, and inflammatory cytokines), but do not establish a specific TrkB-dependent mechanism for accelerating nerve growth.

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.