Creatine: what it is and what the research shows

Creatine is a compound that the body makes itself and also takes in from meat and fish. It helps muscle and brain cells recycle energy quickly. Creatine is best known from sport, but a growing number of studies look at adults in midlife and later life: at muscle, bone and the brain.

This article explains what creatine is, what happens to it in the body, and what human trials have found.

What creatine is

Creatine is a small molecule related to amino acids. The body makes it in two steps, mainly in the liver and kidneys, from three amino acids: arginine, glycine and methionine.^1,2 About 95 percent of the body's creatine is in skeletal muscle, with small amounts in the brain and other tissues.¹

Each day, about 1 to 2 percent of the creatine stored in muscle breaks down into creatinine, which the kidneys remove in urine. The body therefore needs to replace about 1 to 3 grams a day, depending on muscle mass. In people who eat meat and fish, about half of this comes from food, and the body makes the rest. Vegetarians get almost no creatine from food. Their muscle stores tend to be lower, and they may see larger gains when they take creatine.¹

Women tend to eat less creatine than men: in a large US diet survey, women took in about 0.4 grams a day from food and men about 0.7 grams.³ Because women have less muscle, they also store less creatine in total, although the amount per kilogram of muscle is similar or even slightly higher.⁴

How the body handles creatine

Swallowed creatine is absorbed from the gut, and a dedicated transporter carries it into muscle cells. With a normal diet, muscle creatine stores are about 60 to 80 percent full, and supplements can raise them by 20 to 40 percent.¹ A high amount for about a week fills the stores quickly, but 3 grams a day for four weeks leads to a similar rise.⁴ The brain takes up creatine too, although the rise there is smaller, typically about 5 to 10 percent.²

Inside cells, much of the creatine is stored as phosphocreatine. ATP is the molecule cells spend on their work from moment to moment. During short, intense efforts, such as climbing stairs or lifting a heavy bag, phosphocreatine passes its phosphate group to ADP to re-form ATP within seconds. This makes it a rapid energy buffer for muscle cells and for brain cells, which use a great deal of energy.^1,2

What research has looked at

Muscle and strength training. Most research on creatine in later life combines it with resistance training, exercise against a load such as lifting weights:

• A meta-analysis, a study that pools the results of many trials, combined 22 trials with 721 adults whose average ages ranged from 57 to 70. Creatine plus training increased lean tissue mass by 1.4 kilograms more than training with placebo, and improved chest-press and leg-press strength more.⁵ A 2021 analysis of 16 trials found a similar gain of 1.3 kilograms.⁶
• An independent 2026 meta-analysis of 11 trials in adults over 60 confirmed a larger gain in muscle strength with creatine than with training alone.⁷
• In women after menopause, a 2026 meta-analysis of seven trials with 608 women found more lean mass and 7.5 kilograms more leg-press strength with creatine. The benefits were clearest at 5 grams a day or more, combined with resistance training.⁸

Muscle without an exercise programme. A 2026 trial looked at what happens when people take creatine without starting to train. It enrolled healthy adults aged 45 to 65 who did not exercise regularly. In the group who did not join an exercise programme, those taking 10 grams of creatine a day gained about 1.1 kilograms of lean tissue in 12 weeks, while lean tissue in the placebo group stayed about the same. Their bench-press strength also improved more than with placebo.⁹ Lean tissue includes the water that creatine draws into muscle cells, so part of the gain may be water.¹⁰ The groups were small, with 13 people each, and in earlier trials of creatine without training, mostly at lower amounts, the gains were smaller. Across 143 trials, the largest gains in lean mass came when creatine was combined with resistance training.¹¹

Bone and everyday function. Creatine has not been shown to raise bone density, but two trials point to benefits for bone structure. In a two-year trial in 237 women after menopause who all followed an exercise programme, creatine preserved the strength-related shape of the narrow part of the thigh bone near the hip, which declined in the placebo group. The women taking creatine also walked 80 metres faster by the end of the trial.¹² In a one-year trial in 70 adults with an average age of 58, creatine combined with training increased bone area in the lower leg and improved the density of the leg muscles.¹³ In 103 adults with an average age of 68, 3 grams a day for 16 weeks added further gains in strength and physical function when combined with training,¹⁴ and in a 2025 trial, strength recovered faster after strenuous exercise with creatine than with placebo.¹⁵

Memory and thinking. Research on the brain is newer and growing quickly. A 2024 meta-analysis of 16 trials with 492 adults found better memory with creatine than with placebo, and faster responses in tests of attention and processing speed; women showed the larger gain in processing speed.¹⁶ An earlier meta-analysis of memory in healthy people found the clearest benefit in older adults aged 66 to 76, a result that held when the authors re-ran their analysis with a stricter statistical method.^17,18 In a 2026 review of studies in older adults, five of six reported a positive link between creatine and thinking skills, particularly memory and attention, and the authors called for larger trials.¹⁹

Sleep loss and mental tiredness. Creatine has also been tested in the brain under strain. In 15 young adults kept awake through the night, a single large dose of creatine changed markers of energy metabolism in the brain, improved cognitive performance and processing speed, and reduced how tired the volunteers felt, compared with placebo.²⁰ In a 2026 follow-up with 29 adults, a lower single dose reduced the decline in logic, number and attention tasks by up to 12 percent, and women benefited more than men.²¹ These were single large doses tested in a laboratory, and they show how the brain may use extra creatine at times of high demand.

Women around menopause. In a 2026 trial in 36 women in the years around menopause, eight weeks of a small daily amount of creatine hydrochloride, a different form of creatine, improved reaction time and raised creatine levels in the front of the brain compared with placebo.²²

Healthy ageing. In older mice, animals fed creatine had a 9 percent longer median healthy lifespan and performed better in tests of brain function and behaviour.²³ In a US survey that followed 4,041 adults for about 20 years, people who ate at least 1 gram of creatine a day from food had a 15 percent lower risk of death over that period. The link was weaker once lifestyle was taken into account, and studies of this kind show associations rather than cause and effect.²⁴

What the evidence shows overall

The strongest evidence for creatine in later life is for strength and lean mass when it is combined with resistance training, and meta-analyses, including an independent one from 2026, agree on the gain in strength.^5,7 Results for the brain are encouraging but come from smaller trials, and the 2026 trial without exercise is an early but promising signal.^9,19 Many creatine studies were carried out by researchers with links to creatine manufacturers, so larger independent trials will help to show which effects hold most consistently.^9,25

Safety

Creatine has been tested in many clinical trials. In an analysis of 685 of them, side effects were reported by 4.6 percent of people taking creatine and 4.2 percent of people taking placebo, a difference that was not significant.²⁵ In women, a meta-analysis of 29 studies with 951 participants found no serious adverse outcomes and no difference from placebo in total side effects.²⁶ Creatine was also well tolerated in two-year trials in women after menopause.^12,27 A few practical points are worth knowing:

• In the first days, creatine draws water into muscle. With a high-dose loading phase, body weight can rise by 1 to 3 kilograms, mostly water.⁴ In a trial in women, loading did not change body weight compared with placebo.²⁸
• Large single doses can upset the stomach. Taking no more than 5 grams at a time, or splitting a larger amount over the day, helps to avoid this.²⁹
• Creatine raises blood creatinine, a marker used to estimate kidney function, so these estimates can look lower than they are. In a 2026 meta-analysis of 26 studies, kidney function measured with a method that does not rely on creatinine did not change.³⁰ Anyone having blood tests should tell their doctor that they take creatine.
• In a 2025 trial in young men, 5 grams a day for 12 weeks did not change hair growth or the hormone DHT compared with placebo.³¹
• There are no randomised trials in pregnancy yet, and data in people with kidney disease are limited.^2,30

Open questions

• How much of the lean tissue gained without exercise is new muscle, and will larger trials confirm the result?
• Which daily amounts work best for muscle, and which for the brain?
• Will larger trials confirm the benefits for memory in older adults and for thinking in women around menopause?
• Can creatine help preserve bone strength in women after menopause over the long term?
• Does a higher creatine intake support healthy ageing in people, as it did in mice?

Sources

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This article is for general education about an ingredient and the research on it. It is not medical advice. If you have a health condition, are pregnant or breastfeeding, or take medication, talk to a doctor or pharmacist before taking food supplements.

Last reviewed: October 2026