What is creatine? A plain-English guide

People get some creatine from their diet, and the body makes the rest [3]. It is found mostly in meat, fish and other animal foods, and vegetarians have lower levels of it in their muscles [6].

Taking creatine as a supplement raises the amount stored in muscle [3]. The most widely used and studied form is creatine monohydrate [10]. An Olympic expert panel lists creatine among the few supplements with good evidence of benefit for top athletes [3].

Scientists think creatine helps muscle and brain cells recycle the molecule that carries their energy [5].

Researchers have studied creatine for strength, power and lean mass in people doing resistance training [2][3], and for memory [4]. Resistance training means exercise that makes muscles work against a load, such as lifting weights.

Health Canada lets creatine products state two uses [9]. One is building lean muscle alongside resistance training. The other is strength and power in repeated short bursts of intense activity [9].

Does creatine increase strength?

Evidence grade for strength and power output: A, strong. Why this grade

In trials that paired it with resistance training, mostly in men, it did [1][2]. A meta-analysis is a study that pools the results of many earlier studies. A 2026 meta-analysis pooled 63 studies with 1,489 adults doing resistance training [2]. People who trained and took creatine gained more upper- and lower-body strength than those who only trained [2].

In a 2024 review of 23 studies in adults under 50, 20 studies were in men, who gained strength [1]. The 2 studies in women showed no statistically significant gains [1]. Statistically significant means the result is unlikely to be due to chance alone. But those 2 studies had only 40 women in all [1]. And the gap between men and women in upper-body gains may have been due to chance [1]. One author of that review advises Alzchem and Create, two companies that make creatine [1].

Does creatine build lean mass?

Evidence grade for lean mass: A, strong. Why this grade

Lean mass is the part of body weight that is not fat. In the 2026 meta-analysis, creatine plus resistance training increased lean mass more than training alone [2]. Fat mass did not differ significantly between the groups [2]. The authors say the small rise in body weight came mainly from gains in lean mass [2]. Creatine also makes the body hold more water, which adds some weight [10].

Does creatine help memory?

Evidence grade for memory: C, limited. Why this grade

Possibly, but the effect was small and mostly in older adults [4]. A placebo is a dummy supplement that looks the same as the real one. A 2023 meta-analysis pooled 8 randomized trials in healthy people that compared creatine with a placebo [4]. Randomized means chance decides who gets which.

Creatine improved memory scores a little more than placebo did, but results varied a lot between trials [4]. In adults aged 66 to 76 the effect was larger [4]. In people aged 11 to 31 it was close to zero [4].

A 2023 trial published its plan before it began [5]. In it, 123 healthy adults took 5 g of creatine a day for 6 weeks and a placebo for another 6 weeks, in random order [5]. Neither they nor the researchers knew which was which [5]. Memory results leaned toward a small benefit but only came close to statistical significance [5]. There was no clear effect on a reasoning test or on other thinking tasks [5].

Results for vegetarians are mixed [5][6]. In that 2023 trial, vegetarians did not benefit more than meat eaters [5]. An earlier trial in 128 young women was also randomized, blinded and placebo-controlled [6]. It found better memory with creatine in vegetarians, but not in meat eaters [6].

To see what each grade requires, read how we grade evidence.

Table: Doses used in studies (not a recommendation)

These are amounts used in research and limits set for licensed products, not advice for anyone. Talk to a clinician or pharmacist before trying creatine.

A US government fact sheet says creatine is considered safe for short-term use by healthy adults [10]. It says studies have found no consistent side effects except weight gain [10].

In the 2023 trial of 123 adults, 17% reported side effects with creatine and 4% with placebo [5]. The main ones were digestion problems (6% vs 2%) and weight gain (3% vs 0%) [5].

Some people worry about the kidneys, mainly because creatine raises blood levels of a substance called creatinine [7]. A 2025 meta-analysis pooled 12 studies [7]. It found a modest rise in creatinine, which the authors call short-lived [7]. But in studies longer than 12 weeks, the rise showed up again [7]. The authors say the rise likely reflects normal creatine turnover, not kidney damage [7]. They found no significant change in how well the kidneys filter blood [7].

On medicines, a 2026 review found no controlled human studies that directly tested creatine with prescription drugs [8]. Drug databases listed only minor or theoretical warnings, mostly linked to how the kidneys clear substances [8]. The review's author serves on creatine advisory boards and is an inventor on creatine-related intellectual property [8].

If you take prescription medicines, talk to your doctor or pharmacist before combining them with creatine.

• Pregnant or breastfeeding people. Health Canada requires creatine products to advise asking a health care provider before use in pregnancy or breastfeeding [9].
• People with a kidney disorder. Health Canada requires the same advice for anyone with a kidney disorder [9].
• Children and teens. Health Canada's rules for creatine products cover only adults 18 and older [9].
• People taking prescription medicines. The 2026 review's author says a lack of evidence does not mean interactions cannot happen, especially in high-risk groups [8].