What the Evidence Actually Says About Creatine

The baseline: what creatine actually does

Creatine is a compound your body makes naturally and also gets from meat and fish. It helps your muscles produce energy during high-intensity work. When you supplement, you increase the creatine stored in muscle tissue, which may allow slightly more work capacity during resistance training.

That's the mechanism. Now let's look at what the research found in practice.

Muscle building: the evidence

A 2023 systematic review and meta-analysis in Nutrients (Burke et al.) pooled 10 trials in which people did resistance training for at least six weeks, with creatine or with a placebo, and muscle size was measured directly by imaging. The pooled result favoured creatine, but the effect was very small, and its uncertainty range reached zero (0.11, 95% credible interval −0.02 to 0.25). Analyses that looked at the upper and lower body separately found small gains in muscle thickness of roughly 0.10 to 0.16 cm. The authors concluded that creatine combined with resistance training promotes a small increase in muscle size.

So the honest reading is a small edge, not a transformation. You won't gain ten pounds of muscle from creatine. Every trial combined creatine with resistance training, so these results say nothing about taking it without training.

Safety: the kidney question

This is where the myths live loudest. A 2019 systematic review and meta-analysis in the Journal of Renal Nutrition (de Souza e Silva et al.) pooled studies of creatine supplementation and kidney markers and concluded that supplementation did not induce renal damage in the amounts and durations studied.

That conclusion has limits. It describes the doses and time frames that were tested, and it cannot tell you what happens if you already have kidney disease, reduced kidney function, diabetes, high blood pressure or a family history of kidney problems. If any of those apply, talk to your doctor before you start. Don't assume the evidence applies to you.

Memory and brain function: the evidence is mixed

A 2023 systematic review and meta-analysis of randomised controlled trials in Nutrition Reviews (Prokopidis et al.) pooled 8 trials in healthy people. Overall, creatine was associated with better memory test performance than placebo (standardised mean difference 0.29, 95% CI 0.04 to 0.53), but the trials differed a lot from one another (I² = 66%).

The benefit was concentrated in older adults aged 66 to 76 (SMD 0.88, 95% CI 0.22 to 1.55). In the younger group, aged 11 to 31, there was essentially no effect (SMD 0.03, 95% CI −0.14 to 0.20). Dose (about 2.2 to 20 g a day) and trial length did not change the findings.

What that means: there is evidence of a possible memory benefit, mostly in older adults, from a small number of trials that do not all agree. It is not a reason to take creatine for your brain if you are young and healthy, and it says nothing about focus or performance in daily life. If you take creatine for training, any cognitive effect is, at most, a bonus.

How to use it (if you decide to)

Creatine monohydrate is the form used in most research and the cheapest. The studies cited here did not compare forms, so nothing in this article shows that pricier variants (buffered, liquid, bound to other compounds) work better.

A common dose is 3 to 5 grams daily with food. You will also see a "loading phase" of around 20 grams a day for 5 to 7 days. Loading fills your muscle stores faster, while 3 to 5 grams daily gets there over a few weeks, and some people find large loading doses upset their stomach. The studies cited here did not test loading against steady dosing, so treat this as common practice, not a finding from them.

Expect any effect to build over weeks, not days. If you stop taking it, muscle creatine levels generally drift back to normal over a few weeks.

Creatine is not a shortcut. It's a small tool that works only alongside consistent training and good nutrition.

The honest summary

Creatine is neither a miracle nor a scam. It is one of the most studied supplements, the kidney-safety evidence is reassuring in the amounts studied, and the evidence on muscle points to a small benefit when you are already training. On memory, the evidence is mixed and strongest in older adults.

It is cheap and won't give you extraordinary results. If you train seriously and want every small advantage, it's reasonable to use. If you have kidney concerns or related risk factors, ask your doctor first. If you aren't training with weights, don't expect it to do much. And if you're looking for a substitute for good training, food and sleep, it isn't one.