4 Needs context
The human body endogenously produces 1 to 2 grams of creatine per day, primarily in the liver and brain, and excretes approximately 2 grams of creatinine per day in urine.
"so we naturally are producing creatine in two main areas, in the liver and in the brain, and on average, we're producing about 1 to 2 grams... and we excrete through the urine a product called creatinine, about 2." (said at 0:15:26)
The quantitative figures stated by the speaker are well-established physiological values: an average adult endogenously synthesizes approximately 1 to 2 grams of creatine daily to replace the steady, non-enzymatic conversion of creatine and phosphocreatine to creatinine, which is excreted in the urine at a rate of roughly 1 to 2 grams per day. However, systemic endogenous production is primarily an inter-organ process involving the kidneys (which produce the intermediate guanidinoacetate via AGAT) and the liver (which methylates it to creatine via GAMT), with smaller contributions from the pancreas. While the brain does synthesize creatine locally to meet its own metabolic demands due to limited transport across the blood-brain barrier, it is not one of the two primary sites of bulk whole-body creatine production.
A German MRS study comparing 2, 4, and 10 grams of creatine found that 10 grams increased brain creatine content by about 10% in gray matter, white matter, and the thalamus.
"The seminal study was out of Germany, and they did four—2 versus 4 versus 10... and they only they showed that about 10 doubled the percent increase in brain creatine content, but they also measured it in the gray matter, the white matter, and I believe the thalamus, and it all improved by about 10%." (said at 0:40:38)
The speaker is referring to the seminal German proton magnetic resonance spectroscopy (1H-MRS) study by Dechent et al. (1999) from the Max Planck Institute in Göttingen. That study examined the effects of oral creatine supplementation on gray matter, white matter, cerebellum, and thalamus in healthy volunteers, finding an overall average increase in total brain creatine of 8.7% (4.7% in gray matter, 11.5% in white matter, and 14.6% in the thalamus). However, the dosing description was misremembered: the study did not compare 2 g vs. 4 g vs. 10 g doses, but rather administered 4 divided doses of 5 g per day (totaling 20 g/day) for 4 weeks.
- context: Increase of total creatine in human brain after oral supplementation of creatine-monohydra… (The American journal of physiology 1999) · cited 223x in the literature
"The effect of oral creatine supplementation on brain metabolite concentrations was investigated in gray matter, white matter, cerebellum, and thalamus of healthy young volunteers by means of quantitative localized proton magnetic resonance spectroscopy in vivo... Oral consumption of 4 x 5 g creatine-monohydrate/day for 4 wk yielded a statistically significant increase (8.7% corresponding to 0.6 mM, P < 0.001) of the mean concentration of total creatine (tCr) when averaged across brain regions and subjects (n = 6)... A regional analysis resulted in significant increases of tCr in gray matter (4.7%), white matter (11.5%), and cerebellum (5.4%) and was most pronounced in thalamus (14.6% corresponding to 1.0 mM)." (abstract, results, passage verified)
pubmedfull study (doi)
Blood creatinine can be elevated by a very high-protein diet, excessive exercise, or dehydration.
"Creatinine can also be raised with a very, very high-protein diet, excessive exercise, or dehydration." (said at 1:33:14)
Serum creatinine levels can be transiently elevated by strenuous exercise (due to increased muscle breakdown and turnover of creatine to creatinine), dehydration (via hemoconcentration and reduced renal perfusion/prerenal azotemia), and acute ingestion of large amounts of cooked protein/meat (which contains exogenous creatinine formed during cooking). However, high-protein diets generally do not cause sustained elevations in serum creatinine in healthy individuals; a meta-analysis of 19 randomized controlled trials in adults without chronic kidney disease showed that high-protein diets had no significant effect on serum creatinine compared with control diets (SMD 0.08, 95% CI -0.09 to 0.25). Thus, while acute heavy protein/meat intake, excessive exercise, and dehydration are well-recognized non-renal or prerenal causes of transient serum creatinine elevation, dietary protein per se does not chronically raise resting creatinine levels.
In a crossover study of elite rugby players taking 20 to 25 grams of creatine daily for 7 days, dihydrotestosterone (DHT) increased by about 57% while remaining within normal physiological range, while placebo increased DHT by about 40%, and the study did not measure hair loss or thinning.
"So they had elite rugby players do a crossover design... And when they took 20 grams a day, um might have been even 25 grams a day for 7 days, uh during the creatine supplementation phase, they increased the hormone dihydrotestosterone, or DHT... But when they went up, I think it went up by about 57%, but it was still within the physiological range... When they were on placebo, it increased by about 40%. They did not measure hair follicle loss, thinning, cross-sectional area; no dermatologist was involved." (said at 1:34:02)
A 2009 randomized, double-blind crossover study in 20 college-aged rugby players (van der Merwe et al.) examined 7 days of creatine loading (25 g/day) followed by 14 days of maintenance (5 g/day). Dihydrotestosterone (DHT) increased by 56% after 7 days of creatine loading and remained 40% above baseline after the 14-day maintenance phase (all values remained within normal clinical reference ranges). The study measured serum testosterone, DHT, and body composition, and did not measure hair loss, hair thinning, or any dermatological parameters. However, the speaker misattributed the 40% increase to the placebo arm; in the trial, the 40% elevation occurred during the 14-day creatine maintenance period.
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.