Creatine: the best-evidenced supplement, and its stubborn myths

If you could only name one supplement that has genuinely earned its reputation, creatine monohydrate would be near the top of the list. It's cheap, it's been studied for more than 30 years, and its core benefit — helping you do slightly more work in each training session, which compounds into real strength and muscle over months — has held up across hundreds of trials. Creatine also attracts myths like no other supplement: that it wrecks your kidneys, thins your hair, requires a complicated "loading" ritual, or isn't for women. Here's what the evidence actually supports, and where it's honestly still uncertain.

The strength evidence is about as strong as supplement science gets

The headline claim is well established. A 2024 systematic review and meta-analysis of 23 randomized trials in adults under 50 found that creatine plus resistance training beat resistance training alone by a meaningful margin — roughly 4.4 kg more upper-body strength and 11.4 kg more lower-body strength on maximal-strength tests. The mechanism is simple: creatine tops up your muscles' phosphocreatine stores, letting you squeeze out extra reps and slightly heavier loads, and that added training stimulus is what drives the adaptation. It's not a stimulant and it won't help your 10-km time — the benefit is concentrated in short, hard efforts like lifting, sprinting, and jumping.

Creatine also reliably adds a small amount of lean mass — often a couple of pounds over the first weeks, partly muscle and partly water drawn into the muscle cell. If most of your protein comes from a whey shake, creatine pairs fine with it; see creatine with whey protein for how those two commonly sit together in a routine.

Cognition: promising, but don't oversell it

The brain is metabolically hungry and uses creatine too, which is why researchers have looked at whether supplements sharpen thinking. The results are genuinely mixed. A 2024 meta-analysis found a small but statistically significant improvement in memory (SMD 0.31) and in processing-speed and attention times, with hints that effects were larger in people aged 18–60 than in those over 60. But the same analysis found no significant effect on overall cognitive function (p = 0.22) or executive function (p = 0.12).

Two honest caveats: many of these studies are small and use different cognitive tests, and pooling dissimilar outcomes can make a modest signal look bigger than it really is. The most defensible read today is that creatine might help thinking under stress, sleep deprivation, or in older adults — the situations where brain energy is most taxed — but it is not a proven nootropic for well-rested, healthy people.

The kidney myth, and where caution is real

This is the stubbornest myth. It traces largely to a single 1998 case report of a young man who already had kidney disease and whose doctors misread the situation. Here's the key point: creatine supplementation raises serum creatinine, a blood marker labs use to estimate kidney function — but that's the expected result of putting more creatine into your body, not a sign of damage. Decades of controlled research since then, across thousands of participants, have found no evidence that recommended doses harm the kidneys of healthy people.

"Healthy" is the operative word. Cleveland Clinic advises caution — and a conversation with your clinician first — if you have kidney disease, liver disease, or diabetes, or if you're pregnant or breastfeeding, because those groups simply haven't been well studied. If you ever get a blood test, mention that you take creatine so a raised creatinine reading isn't misinterpreted. This is general information, not medical advice; your doctor or pharmacist should make the call for your situation.

The hair-loss scare rests on one study that didn't even measure hair

The idea that creatine causes baldness comes from a single 2009 study of college rugby players. After a week of heavy loading (25 g/day) and two weeks at 5 g/day, the creatine group's dihydrotestosterone (DHT) — a hormone linked to male-pattern hair loss — rose about 56%, then settled around 40% above baseline. That sounds alarming until you read the details: the study never measured hair at all, the creatine group started with lower baseline DHT than placebo, total testosterone didn't change, and the finding has never been replicated.

More recent work fills the gap. A 2025 randomized controlled trial in 38 resistance-trained men took 5 g/day for 12 weeks and directly measured hair follicle health — count, density, thickness — alongside hormones. It found no significant difference between creatine and placebo in DHT, the DHT-to-testosterone ratio, or any hair outcome. The authors called it "strong evidence against the claim that creatine contributes to hair loss." If you're genetically prone to male-pattern balding, that's worth discussing with a dermatologist — but the current evidence doesn't pin it on creatine.

Loading versus a simple 3–5 g a day

You don't need to load. There are two valid routes to the same destination — muscles that are roughly 20–40% more saturated with creatine:

Both are drawn from the ISSN's review of common creatine questions. Single servings above about 10 g can cause GI distress, which is one reason the plain 3–5 g daily approach is popular. Monohydrate is the form with by far the most evidence; the fancier, pricier forms haven't been shown to beat it.

Who responds less

Creatine isn't equally dramatic for everyone. People who already carry high muscle creatine — often regular red-meat and seafood eaters — have less room to top up and may notice smaller gains. Vegetarians and vegans, who get little dietary creatine, tend to respond more. Women tend to have higher resting intramuscular creatine concentrations than men — even though their total body creatine and daily synthesis are lower — which may leave a bit less headroom to top up and partly explain the smaller measured effects in some female studies. There is no reliable at-home genetic test that predicts your personal creatine response, so be skeptical of any product that claims to — our DNA supplement report sticks to what published genetics can actually support and won't promise a "creatine gene" readout that the science doesn't back.

Does caffeine cancel out creatine?

This worry comes from a 1996 study that paired creatine loading with a high dose of caffeine and found the caffeine appeared to blunt creatine's performance benefit. It has never been cleanly replicated, and the doses were high. A more recent controlled study tested coffee and caffeine powder alongside creatine loading and found no significant impairment of performance — but it did note mild stomach discomfort in some people taking creatine with anhydrous caffeine powder, with none reported when the caffeine came from coffee.

Practical takeaway: a pre-workout coffee is very unlikely to undo your creatine. If your combined pre-workout gives you an upset stomach, that's the more realistic issue — space them out or take creatine at a different time of day. You can look at how these two commonly interact on our caffeine with creatine page, or run your own combination through the interaction checker.

Women and creatine: understudied, but encouraging

Most creatine research was done in men, which matters because women naturally carry 70–80% lower endogenous creatine stores. In premenopausal women, supplementation has been linked to strength gains of roughly 18–25% on one-rep-max tests and anaerobic improvements of 10–22%, without large weight changes. In postmenopausal women, higher doses (about 0.3 g/kg/day) combined with resistance training have shown benefits for muscle size, strength, and functional performance. There's early, preliminary interest in mood too — one small trial in adolescent females paired 4 g/day with an antidepressant and saw a 56% drop in depression ratings — but that's a specific clinical context, not a general recommendation.

The big gap is pregnancy: there are essentially no human supplementation trials, so pregnant and breastfeeding women should treat creatine as unstudied and defer to their obstetric provider.

Bottom line

Creatine monohydrate is the rare supplement where the hype and the evidence roughly match: it modestly but reliably boosts strength and lean mass when paired with training, it's inexpensive, and its safety record in healthy people is excellent. The kidney and hair-loss fears rest on thin, unreplicated evidence, and the cognition benefits are real-but-modest and still shaking out. Skip the loading phase if you'd rather keep it simple — 3–5 g a day gets you there in a few weeks. Talk to your doctor or pharmacist first if you have kidney or liver disease, diabetes, or are pregnant or breastfeeding, and if you take other supplements or medications, run the combination through the checker before you stack.