01 / Mechanism

Why it works.

Creatine is a small molecule synthesized from glycine, arginine, and methionine in the liver and kidneys. Once in tissue, creatine kinase phosphorylates it into phosphocreatine, which serves as a rapidly mobilizable phosphate donor to regenerate ATP from ADP. The system dominates energy supply in the first 10–15 seconds of high-intensity work — the rep range that builds strength and power output.

Supplementing 3–5 g/day for several weeks expands the muscle phosphocreatine pool by ~10–40% above baseline, with the largest increases in people whose baseline is lowest (vegetarians, older adults). That headroom translates into more reps, slightly more weight, and a modest but real increase in lean mass over training cycles [Kreider 2017].

The brain has its own phosphocreatine pool, refreshed by a separate but slower transport across the blood-brain barrier. That separation is why the cognitive benefits of supplementation seem to require larger doses or longer time courses than the muscle effects, and why the people who benefit most are those with constrained substrate — sleep-deprived and vegetarians.

02 / Dosing

The boring protocol.

Phase	Dose	Timing	Note
Standard maintenance	3–5 g/day	Any time, daily	Plateau in ~4 weeks
Loading (optional)	20 g/day in 4 doses × 5–7 days	Then 3–5 g/day	Faster saturation, more GI side effects
Cognitive target	5–10 g/day	Daily, ongoing	Higher doses studied for brain effects
Heavier athletes	5 g/day per ~70 kg	Daily	Larger muscle mass, larger pool to fill

Monohydrate is the standard

HCl, buffered ("Kre-Alkalyn"), ethyl ester, and other novel forms have not outperformed monohydrate in head-to-head trials, and they cost more. Monohydrate is what every major trial used. Buy that.

Timing relative to workouts does not meaningfully matter for the muscle effect — daily dosing matters more than the hour. Co-ingesting with carbs or protein modestly increases uptake via insulin, but the saturation endpoint is the same. Cycling off is not necessary.

03 / Cognitive evidence

Brain creatine, specifically.

Rae and colleagues showed in 2003 that 5 g/day of creatine for six weeks improved working memory (backward digit span) and Raven's Progressive Matrices in young vegetarian adults — both tasks that load processing speed [Rae 2003]. A 2018 systematic review by Avgerinos and colleagues pooled the data and concluded that creatine appears to improve short-term memory and intelligence/reasoning, with effects most consistent under conditions of stress, sleep deprivation, or low dietary intake [Avgerinos 2018].

Translation: an already-replete omnivore eating beef daily may not get a noticeable cognitive bump from supplementation. A vegetarian, a sleep-deprived shift worker, or an older adult with declining endogenous synthesis is much more likely to feel something. This is consistent with the pool-saturation model — you can't fill what's already full.

Bone-density signal is newer. Trials in postmenopausal women combining creatine with resistance training have shown attenuated loss of proximal femur bone mineral density over 12 months [Chilibeck 2015]. The effect is small, real, and worth tracking.

04 / The hair-loss question

One study, cited a lot.

In 2009, van der Merwe and colleagues studied 20 college-aged rugby players given a creatine loading protocol. After seven days of loading, DHT (dihydrotestosterone) rose by roughly 56% from baseline and remained about 33% above baseline through three weeks of maintenance dosing [van der Merwe 2009]. This is the single study every forum thread is referencing.

Two caveats matter. First, the absolute DHT values stayed within the normal physiological range — the percent change was eye-catching, the biology less so. Second, the study did not measure hair loss, hair density, follicle count, or anything else hair-related. It measured a hormone. Subsequent literature looking at creatine's effects on androgens has not consistently replicated the magnitude of the DHT change, and no controlled study to date has demonstrated creatine causing hair loss. Someone with strong familial androgenic alopecia who notices accelerated shedding on creatine is reasonable to discontinue; a population-level concern is not supported.

05 / Side effects

What's real.

Water retention (~1–2 kg). Intracellular, not bloat. This is part of how creatine works, not a side effect to fight.
GI discomfort during loading. Resolves at maintenance dose. Skip loading if it bothers you — endpoint is the same.
Kidney function (clinical). Creatine raises serum creatinine without raising actual creatinine clearance — a measurement artifact, not kidney damage. Tell your clinician you take it before labs. People with pre-existing renal disease should clear use individually.
Muscle cramping. Repeatedly studied, not supported in healthy populations.

06 / Cost

Cheap, period.

Form	Typical price	Cost per day (5 g)	Note
Monohydrate (bulk)	$15–25 / kg	~$0.10	Buy Creapure if you want a guaranteed source
Capsules	$25–40 / month	$0.80–$1.30	Convenience tax
HCl / "advanced"	$40–60 / month	$1.30–$2.00	No clinical advantage

07 / Bottom line

Where creatine sits.

Creatine is the rare supplement where the evidence is unusually strong, the dose is unusually simple, and the cost is unusually low. If someone trains, is vegetarian, sleeps poorly, or is over 50, the case is straightforward. Monohydrate, 3–5 g/day, indefinitely. See the longevity hub for context and the sleep stack piece for how creatine fits alongside other interventions.

08 / References

The evidence base.

Rae C, Digney AL, McEwan SR, Bates TC. Oral creatine monohydrate supplementation improves brain performance: a double-blind, placebo-controlled, cross-over trial. Proceedings of the Royal Society B, 2003;270(1529):2147–2150. [Rae 2003]
Avgerinos KI, et al. Effects of creatine supplementation on cognitive function of healthy individuals: A systematic review of randomized controlled trials. Experimental Gerontology, 2018;108:166–173. [Avgerinos 2018]
van der Merwe J, Brooks NE, Myburgh KH. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clinical Journal of Sport Medicine, 2009;19(5):399–404. [van der Merwe 2009]
Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition, 2017;14:18. [Kreider 2017]
Chilibeck PD, et al. Effects of creatine and resistance training on bone health in postmenopausal women. Medicine & Science in Sports & Exercise, 2015;47(8):1587–1595. [Chilibeck 2015]
Roschel H, et al. Creatine supplementation and cognitive performance in elderly individuals: a systematic review. Nutrients, 2021;13(2):586. [Roschel 2021]
Forbes SC, et al. Effects of creatine supplementation on brain function and health. Nutrients, 2022;14(5):921. [Forbes 2022]
Kious BM, Kondo DG, Renshaw PF. Creatine for the treatment of depression. Biomolecules, 2019;9(9):406. [Kious 2019]

About this profile

Last reviewed against evidence: 2026-05-12. This profile is editorial reference content, not sponsored. Wellness Radar does not currently carry affiliate links for specific creatine brands. Educational reference, not a prescription — if you have kidney disease or are taking medications metabolized by the kidneys, raise this with your clinician before starting.

Creatine