Creatine: What the Evidence Actually Shows

Creatine helps your muscles make quick energy. Your body stores it in muscle as phosphocreatine.

During hard effort, like a heavy lift or a sprint, phosphocreatine helps refill ATP, the molecule your cells burn for energy.

Taking creatine as a supplement raises the amount stored in your muscle. More stored creatine means your muscles can make ATP faster during short, intense bursts of work.

This is why creatine is the most studied supplement in sports nutrition. Decades of trials point to real, measurable effects on strength and muscle size^[9][10][11].

Yes, this is the best supported effect of creatine.

A 2023 meta-analysis found that creatine combined with resistance training increases muscle hypertrophy across different muscle regions, not just overall body mass^[5].

A 2022 meta-analysis looked at lean body mass results across age, sex, and exercise type.

Creatine plus resistance training increased lean mass more than training alone, in both younger and older adults, and in men and women^[6].

A newer 2025 trial confirmed this again, showing lean body mass gains with creatine were larger when it was combined with resistance training, though creatine alone had some effect too^[1].

The strength benefit seems to come from two things working together:

• More stored energy for each set, which may allow slightly more reps or weight over time
• Faster recovery between sets, which supports harder training sessions^[9][10]

Muscle loss with age, called sarcopenia, is a major reason older adults lose strength and independence. Creatine has been studied here specifically.

A 2017 meta-analysis found that creatine supplementation during resistance training increased lean tissue mass and strength in older adults more than resistance training alone^[12].

A later 2021 meta-analysis looked closer at how creatine is taken.

It found that ingestion strategy, such as dosing timing and amount, may matter for how well older adults respond in terms of lean mass and strength^[8].

This is where the evidence gets weaker. Creatine's main energy pathway supports short, powerful efforts, not long steady ones.

A 2023 review looked at creatine and endurance performance.

It found some benefit for events that include short surges or sprints within a longer race, like a final sprint at the end of a long run^[4].

For pure steady state endurance, like a long slow run with no sprinting, the evidence for creatine helping is much thinner. It may also add a small amount of water weight, which could be a downside for some endurance athletes^[4][9].

A 2024 narrative review looked at creatine use beyond typical male athlete populations, including women, vegans, and clinical groups^[3].

Vegans and vegetarians tend to have lower baseline creatine stores, since dietary creatine comes mainly from meat and fish. This may mean they see a bigger relative boost from supplementing^[3].

Women's creatine needs and responses may shift across the menstrual cycle and life stages like pregnancy and menopause, though this research is still early^[3].

A 2021 review looked specifically at creatine use in children and adolescents, mostly in the context of sports and some clinical conditions^[7].

Short term use in young athletes has not shown major safety red flags in the available studies.

That said, the research base in this age group is much smaller than in adults, so caution and guidance from a pediatric professional makes sense^[7].

Creatine is one of the most studied supplements for safety, not just performance.

The International Society of Sports Nutrition's position stand reviewed decades of data and found creatine to be safe for healthy people at recommended doses^[11].

Common concerns you may have heard about include:

• Kidney damage, which has not been shown in healthy people using standard doses^[11]
• Dehydration or cramping, which studies have not confirmed as a real risk^[11]
• Water retention, which is real but mostly reflects water stored inside muscle cells, not bloating^[9]

A 2021 update review reached a similar conclusion, describing creatine's safety profile as well supported across many years of use in athletes and clinical populations^[10].

A 2024 review of top sports supplements listed creatine among the small handful with strong enough evidence to be considered a safe, effective choice for performance goals^[2].

Study protocols commonly use one of two approaches:

• A loading phase of about 20 grams a day for five to seven days, followed by a lower daily maintenance dose
• A steady daily dose from the start, without loading, which takes longer to fully saturate muscle stores^[9][10]

Creatine monohydrate is the form used in almost all of the strongest studies. Other forms exist on the market, but they do not have the same depth of evidence behind them^[3][9].