Bryan Johnson · 2025-08-28 · Bryan Johnson (host), Jesse James West

“Bodybuilding Destroyed My Hormones”: Jesse James West on Longevity, Fitness, and Self-Worth

6 research-tied claims examined: 1 contradicted 2 overstated 2 supported 1 unverified

Contradicted by research

0:48:28 Jesse James Westcontradictedvery low

Wearing polyester underwear lowers testosterone levels.

"Do you do you believe in the whole like you can't wear a certain type of underwear type thing that it lowers test? I was going to ask like there's like a certain material people avoid like polyester." (said at 0:48:28)

There is no evidence in human clinical trials demonstrating that wearing polyester underwear lowers serum testosterone levels. In the primary experimental study investigating the effects of continuous wearing of polyester versus cotton undergarments over 24 months (conducted in dogs), polyester fabric caused reductions in sperm count and motility, but serum hormone levels (including testosterone, LH, FSH, and prolactin) showed no significant changes (P > 0.05).

contradicts: Effect of different types of textile fabric on spermatogenesis: an experimental study. (Urological research 1993) · cited 15x in the literature
"There were insignificant changes (P > 0.05) in hormones during the study." (abstract, results, passage verified)
pubmed full study (doi)

Overstated

0:42:23 Bryan Johnson (host)overstatedlow

Psilocybin, ketamine, LSD, and ibogaine possess the strongest anti-aging properties among psychedelics, whereas heroin, methamphetamine, cocaine, and fentanyl accelerate aging.

"So yeah, it was if I remember correctly psilocybin, ketamine, LSD, uh ibogaine, and then I think the ones clearly that did not have anti-aging, actually were aging, were heroin, meth, cocaine, fentanyl is not an anti-aging." (said at 0:42:23)

The assertion that psilocybin, ketamine, LSD, and ibogaine possess strong anti-aging properties overstates very preliminary experimental and observational evidence, while the assertion that illicit stimulants and opioids accelerate biological aging is consistent with observational literature. Small pilot trials have observed decreases in next-generation epigenetic aging markers following ketamine infusion therapy in patients with depression or PTSD, and rodent work has explored psilocybin on lifespan; however, robust clinical evidence demonstrating anti-aging or life-extension effects in humans is lacking for psilocybin, LSD, and ibogaine. Conversely, epidemiological and epigenetic clock studies consistently demonstrate that chronic exposure to substances such as opioids (heroin, fentanyl), methamphetamine, and cocaine is associated with significant biological and epigenetic age acceleration.

supports: Epigenetic clock analysis in methamphetamine dependence. (Psychiatry research 2022) · cited 7x in the literature
"Following adjustment for confounding factors, MA dependence was significantly associated with accelerations in PhenoAge, GrimAge, and DNAmTL, as well as alterations in DNAm-based age-predictive factors (beta-2-microglobulin, granulocytes, and naive cluster of differentiation 4+ T cells)." (abstract, results, passage verified)
pubmed full study (doi)
partial: Epigenetic aging and DNA methylation biomarker changes following ketamine treatment in pat… (Translational psychiatry 2025) · cited 2x in the literature
"We observed a reduction in epigenetic age in the OMICmAge, GrimAge V2, and PhenoAge biomarkers." (abstract, results, passage verified)
pubmed full study (doi)
partial: Psilocybin and human longevity. (npj aging 2026)
"These findings highlight the need for rigorous mechanistic and epidemiological studies before inferring human anti-aging effects of psychedelics." (abstract, conclusions, passage verified)
pubmed full study (doi)
supports: Substance use and epigenetic age acceleration: Associations with alcohol, tobacco, illicit… (Drug and alcohol dependence 2026)
"Binary measures of illicit opioid use (β=0.417, p = 5.913e-11; β=0.180, p = 0.010) and non-prescription opioid use (β=0.264, p = 1.744e-09; 0.001; β=0.127, p = 0.008), as well as a continuous measure of SUD severity (β=0.061, p = 6.608e-06; β=0.039, p = 0.008) were positively associated with AgeAccelGrim2 and DunedinPACE, respectively." (abstract, results, passage verified)
pubmed full study (doi)

0:57:45 Bryan Johnson (host)overstatedlow

Following an international flight, it takes the human body approximately 15 days to fully recover its physiological architecture and restore blood glucose regulation.

"It's 15 days afterwards, your body is still trying to recover its architecture. Your body fully doesn't restore, you know, blood glucose is messed up. So, it really has this compounded long-term effect." (said at 0:57:45)

The claim that the human body takes 15 days to recover its overall physiological architecture and blood glucose regulation after an international flight overstates the published evidence. A large observational study analyzing wearable sleep tracker data across a 15-day post-travel window (PMID 40127035) found that while sleep duration recovers within ~2 days, sleep timing and sleep architecture resynchronize very slowly and had not returned to baseline by day 15. However, clinical studies measuring physiological markers of circadian disruption (such as salivary cortisol levels, sleep duration, and perceived jet lag symptoms) demonstrate normalization within approximately 7 days following long-haul flights across multiple time zones (PMID 36367300). Furthermore, published evidence does not support a 15-day persistent impairment in blood glucose regulation from a single international travel event.

contradicts: Effects of long-haul transmeridian travel on physiological, sleep, perceptual and mood mar… (Chronobiology international 2022) · cited 14x in the literature
"Following LHTT in an eastward direction across eight time-zones, it took seven days for perceived jet lag, physiological markers for circadian rhythm and sleep to normalize in Olympic team support staff." (abstract, conclusions, passage verified)
pubmed full study (doi)
partial: Insights about travel-related sleep disruption from 1.5 million nights of data. (Sleep 2025) · cited 13x in the literature
"In contrast, changes in sleep timing and sleep architecture were considerably slower to recover, with sleep timing not returning to baseline after 15 days." (abstract, results, passage verified)
pubmed full study (doi)

Supported by research

0:58:33 Bryan Johnson (host)supportedhigh

Drinking mineralized liquid, such as electrolyte water or salted tea, causes less frequent urination than drinking plain, unmineralized water.

"You know, if you mineralize the liquid, it has less of an effect. So either if you have salt in tea or electrolytes. If you drink straight water, it's not as mineralized, then you will urinate more." (said at 0:58:33)

Randomized crossover trials consistently demonstrate that adding electrolytes (particularly sodium) to water or consuming mineralized/electrolyte solutions leads to lower cumulative urine volume and greater fluid retention compared to drinking plain water. Ingesting large volumes of plain water rapidly decreases plasma osmolality, which suppresses antidiuretic hormone (vasopressin) and triggers a transient diuresis. In contrast, electrolyte-containing beverages maintain serum osmolality, attenuating the diuretic response and reducing post-ingestion urine output.

supports: A randomized trial to assess the potential of different beverages to affect hydration stat… (The American journal of clinical nutrition 2016) · cited 141x in the literature
"Total urine masses (mean ± SD) over 4 h were smaller than the still-water control (1337 ± 330 g) after an oral rehydration solution (ORS) (1038 ± 333 g, P < 0.001)..." (abstract, results)
pubmed full study (doi)
supports: Impact of Nuun Electrolyte Tablets on Fluid Balance in Active Men and Women. (Nutrients 2020) · cited 10x in the literature
"Nuun tablets resulted in a lower urine output compared to water, with fluid balances for both concentrations more favorable compared to water ( p < 0.05), beginning at 2 h post-ingestion and continuing at the 3 h and 4 h times." (abstract, results, passage verified)
pubmed full study (doi)
supports: Factors influencing the restoration of fluid and electrolyte balance after exercise in the… (British journal of sports medicine 1997) · cited 122x in the literature
"Ingestion of large volumes of plain water will inhibit thirst and will also promote a diuretic response. If effective rehydration is to be maintained for some hours after fluid ingestion, drinks should contain moderately high levels of sodium..." (abstract, results, passage verified)
pubmed full study (doi)

0:59:20 Bryan Johnson (host)supportedmoderate

Urinary stream speed and peak urine flow rate naturally decline with biological age.

"Your capacity, but also it gives you a biological age, because you know urine speed is biologically aged. So as you age, your urine stream decreases in overall capacity." (said at 0:59:20)

Extensive urodynamic literature and uroflowmetry nomograms confirm that peak urinary flow rate (Qmax) and urinary stream velocity progressively decline with advancing age in adults, particularly in men due to progressive detrusor changes and prostatic growth. Observational and urodynamic studies consistently demonstrate a negative correlation between chronological age and maximum flow rate.

supports: Age, gender, and voided volume dependency of peak urinary flow rate and uroflowmetry nomog… (Indian journal of urology : IJU : journal of the Urological Society of India 2009) · cited 49x in the literature
"Qmax values in adult males were significantly higher than in the elderly and Qmax values in young females were significantly higher than in young males. Qmax values in males increased with age until 15 years old; followed by a slow decline until reaching 50 years old followed by a rapid decline after 50 years old even after correcting voided volume." (abstract, results, passage verified)
pubmed full study (doi)
supports: Reassessing Normal Voiding Standards: A Cross-Sectional Study Based on Medical Professiona… (Journal of clinical medicine 2024) · cited 8x in the literature
"Notably, women exhibited higher Q max and Q ave rates irrespective of their IPSS scores, contrasting with men whose flow rates declined with age and LUTS severity." (abstract, results, passage verified)
pubmed full study (doi)

No source found (not proven false)

0:59:45 Jesse James Westunverifiedvery low

Astronomers discovered a black hole with a mass 300 million times that of our sun.

"I read the other day that a black hole was discovered that is 300 million times the size of our sun." (said at 0:59:45)

No published record matching the specific discovery of a black hole with a mass or size 300 million times that of the Sun 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.