Creatine monohydrate has been studied for decades, mostly in young athletes. In the last few years it has become one of the fastest-growing supplements in the US, bought more and more by women and older adults. That shift is broadly supported by the research, with a few caveats worth knowing.
What creatine does
Creatine helps muscle cells regenerate ATP, the fuel used in short, hard efforts. The body makes some, and meat and fish supply more, but muscle stores are not full in most people. Supplementing raises them, which is why the clearest effect is on strength and power when you train.
Strength and muscle with age
From middle age, muscle mass and strength decline. Several reviews of controlled trials in older adults have found that creatine taken alongside resistance training increased lean mass and strength more than training alone. The important word is alongside: creatine does not replace lifting, it makes the lifting count for more.
Women
Women were under-represented in early research. Reviews published since 2021 describe similar benefits from resistance training with creatine, and researchers are now studying it across life stages. The evidence is growing, but it is thinner than for men.
The brain: promising, not settled
The brain uses creatine too. A 2023 meta-analysis of randomized trials found small improvements in memory in healthy adults, with larger effects in older people. The trials were small and varied, so treat this as an interesting signal rather than a reason to buy.
How people take it
- 3–5 g a day of creatine monohydrate is the dose used in most long-term research. Muscle stores fill in about three to four weeks.
- A loading phase (around 20 g a day in split doses, for five to seven days) fills stores faster but is not necessary, and it is more likely to upset the stomach.
- Timing matters little; taking it every day matters most.
- Monohydrate is the form behind nearly all the evidence. Other forms cost more without better results.
Safety, plainly
At these doses creatine has a long safety record in healthy adults. Two practical notes. Some people gain two to four pounds early on, mostly water held in muscle. And creatine raises creatinine on a blood test, a marker doctors use to estimate kidney function, so tell your doctor you take it. If you have kidney disease, ask before you start.
Supplements are not approved before they are sold, so look for a third-party testing mark or a certificate of analysis showing identity and purity.
Sources
- Kreider RB et al., International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation, Journal of the International Society of Sports Nutrition, 2017.
- Smith-Ryan AE et al., Creatine supplementation in women's health: a lifespan perspective, Nutrients, 2021.
- Prokopidis K et al., Effects of creatine supplementation on memory in healthy individuals: a systematic review and meta-analysis of randomized controlled trials, Nutrition Reviews, 2023.
This guide is general information, not medical advice. Talk to your doctor or pharmacist before starting a supplement if you are pregnant or nursing, take medication, or have a medical condition.