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What Does Creatine Do? Benefits, Evidence and Who It Is For
In this article
- What is creatine?
- What does creatine do to the body?
- What is creatine good for in the UK, officially?
- Is creatine a steroid?
- Does creatine actually build muscle?
- Can you take creatine without working out?
- Is creatine good for men over 40 and 50?
- Is creatine good for seniors?
- Is creatine good for anti-ageing, skin or wrinkles?
- What about the brain?
- Is creatine good for you, and is it worth taking?
- Creatine pros and cons
- Side effects and safety, briefly
- What we don't know
- Frequently asked questions
Creatine gives your muscles more of the fuel they burn in the first few seconds of hard effort. Taking 3 to 5 g a day raises the creatine stored in muscle by about 20%, and that lets you squeeze out a little more in sprints, heavy lifts and the last reps of a set. Over weeks of training, that small edge adds up to more strength and about a kilogram more lean mass than training alone. That is the proven part, and in the UK it is the part a supplement is allowed to claim. Everything else you have heard, about the brain, ageing, skin and mood, ranges from promising to unfounded, and this article says which is which.
- What it is: a compound your body makes and you eat in meat and fish, stored in muscle as an energy buffer
- Proven: better performance in repeated short, intense efforts; more strength and lean mass with resistance training
- Authorised UK wording: increases physical performance in successive bursts of short-term, high intensity exercise, at 3 g (grams) a day; and, for adults over 55, enhances the effect of resistance training on muscle strength
- Promising, not authorised: memory in older adults
- Unfounded: anti-ageing, wrinkles, "natural steroid"
What is creatine?
Creatine is a small molecule made from three amino acids. Your liver and kidneys produce about a gram a day, and an omnivore eats another gram or two in meat and fish; plant foods contain essentially none.1 Which foods contain creatine is here. About 95% of it sits in skeletal muscle, where it is converted to phosphocreatine, a reserve that regenerates the muscle's immediate energy currency, ATP, during the first five to ten seconds of maximal effort.
Most people's muscles are around two-thirds full. Supplementing takes them to the ceiling, roughly a 20% increase, in about six days with a loading dose or about four weeks at 3 to 5 g a day, and keeps them there for as long as you continue.2 That is the whole mechanism. How quickly it fills, and what you notice, is here.
What does creatine do to the body?
| Effect | What the evidence shows | How strong |
|---|---|---|
| Short, intense performance | More power and more repetitions in efforts under about 30 seconds: sprints, jumps, heavy sets. The most replicated finding in sports nutrition3 | Strong |
| Strength | Greater strength gains from resistance training than training alone, with the biggest difference in untrained people and at low-to-moderate doses4 | Strong |
| Muscle | About 1.1 to 1.4 kg more fat-free mass than training alone over a typical trial, in both novice and experienced lifters5, 6 | Strong |
| Body water | About 0.8 to 0.9 kg of water drawn into muscle cells in the first weeks; not under the skin, not fat7 | Strong |
| Fat | No increase and no meaningful decrease5 | Strong |
| Memory | A small improvement in healthy adults, concentrated in those over 65; moderate certainty for memory, low for other cognitive measures8, 9 | Moderate for memory, limited otherwise |
Two things on that list are worth saying plainly. Creatine does not build muscle by itself: it lets you train slightly harder, and the training builds the muscle. And the water it adds is inside the muscle, which is why people on creatine look fuller rather than softer. The full picture on weight is here.
What is creatine good for in the UK, officially?
UK food law only allows a supplement to make health claims that have been authorised after a scientific review, and creatine has two. The first: creatine increases physical performance in successive bursts of short-term, high intensity exercise, obtained with a daily intake of 3 g; drink normally alongside it, since no water target is evidenced. The second, added later: daily creatine consumption can enhance the effect of resistance training on muscle strength in adults over the age of 55, at 3 g a day with regular resistance training. Those sentences are the ceiling of what any UK product may say on its label.
Everything else on this page describes research, not a product. Memory, mood, bone and ageing are not authorised claims, and no product may promise them.
Is creatine a steroid?
No. Anabolic steroids are synthetic hormones that act on the body's testosterone receptors. Creatine is a nutrient your body already makes and that you eat in a steak; it has no hormonal action and no effect on testosterone.3, 10 It is legal and sold as a food supplement.
Does creatine actually build muscle?
Indirectly, and only with training. Creatine plus resistance training produces about a kilogram more lean mass than training plus placebo over eight to twelve weeks.5, 6 Without training there is no stimulus for muscle to grow. Creatine is a training aid, not a replacement for training.
Can you take creatine without working out?
You can, and it is not harmful, but for strength or size you will get nothing, because those come from training. You will fill your stores and gain the water. The possible memory effect in older adults did not depend on exercise,8 and vegetarians and vegans, who start with lower stores, are brought level with everyone else.1
Is creatine good for men over 40 and 50?
The evidence here is most encouraging. Men over 40 lose muscle and strength gradually, and faster after 50. Across 22 trials in adults with a mean age of 57 to 70, creatine combined with resistance training produced 1.37 kg more lean tissue and greater upper- and lower-body strength than training with placebo.11 A later analysis found the benefit held even when creatine was taken only on training days.12 The over-55 strength claim above rests on this research. Collagen for men has the muscle trials in men.
The caveat is in every one of those trials: the men were lifting weights. Creatine for a sedentary 50-year-old has not been shown to preserve muscle. Creatine for a 50-year-old who starts lifting twice a week has.
The testosterone, hair and libido questions are on creatine for men. For women the picture is similar: creatine for women covers it, the postmenopausal trials are on creatine in perimenopause and menopause, and can you take collagen and creatine together the pairing.
Is creatine good for seniors?
For strength and muscle with resistance training, yes, and the over-55 claim is authorised for exactly that use.11 Great Britain's register carries a second creatine sentence: "Daily creatine consumption can enhance the effect of resistance training on muscle strength in adults over the age of 55." Its conditions: 3 g a day, taken with resistance training done at least three times a week for several weeks at 65 to 75% of the most you can lift once, with the load increasing over time. Without the training, the sentence does not apply: in 200 older women, 3 g a day for two years without an exercise programme changed nothing that was measured, bone, lean mass or strength.14 For memory, the benefit is concentrated in adults aged 66 to 76 and not yet strong enough to stand alone.8 Check with a GP first if you have reduced kidney function or take regular medication, because creatine raises blood creatinine and can muddle kidney tests. Side effects, kidneys and who should check first are covered here.
Is creatine good for anti-ageing, skin or wrinkles?
Not for creatine taken by mouth. No trial of oral creatine we found has measured skin, wrinkles or any marker of biological ageing; the skin studies tested creams. The ageing research is about muscle and strength in older adults who train, and about memory. Anyone selling creatine as anti-ageing is selling the muscle research under another name.
What about the brain?
The brain holds its own creatine store, which supplements raise more slowly and at higher doses than muscle. Pooled trials show a small memory improvement with moderate certainty, weaker signals for attention and processing speed, and no change in overall cognition.8, 9 The effect is largest in older adults. In August 2024 the UK committee that assesses health claims refused a claim for creatine and cognition. The wording put forward was that daily supplementation "can contribute to improved cognitive function"; of ten trials submitted, only one used 3 g a day or less (22 people on 2.2 g for six weeks), and it found no difference from placebo on any test.15 Any brain effect in the trials belongs to larger doses, longer courses or older adults. It is a real field and an over-claimed one: a possible extra, with the muscle evidence the main case. The trial-by-trial account, including the depression and ADHD record, is on creatine and the brain.
Is creatine good for you, and is it worth taking?
Creatine is good for you in the specific sense the trials measured: more work in repeated short efforts and, with training, a little more strength and lean mass; it is not a general tonic. If you train with short, hard efforts and will take it every day, yes: it is cheap, the best-studied supplement there is, and reliable even if modest. For endurance only, the case is weak. Without training, it rests on the memory research and on topping up a low dietary intake: clearest for vegetarians and older adults, smaller for everyone else.
The dose is 3 to 5 g a day of creatine monohydrate, the form in nearly every trial. A beginner's first 30 days. How much to take for your bodyweight is here, when to take it is here, and whether to load is here. Whether gummies work, and what to check.
Creatine pros and cons
People ask about the downside of creatine almost as often as they ask what it does, so here is the whole ledger, with the strength of the evidence beside each line.
| Pro | Con | Evidence |
|---|---|---|
| More work in repeated short, hard efforts: the authorised UK wording, at 3 g a day3 | About 0.8 to 0.9 kg of water held inside muscle in the first weeks; in seven dancers, in a trial with a supplier-linked author, body water rose 0.5 kg7, 16 | Strong on both sides |
| More lean mass and strength with resistance training: 1.37 kg more lean tissue across 22 trials of 721 older adults11 | An upset stomach when a single serving is 10 g: in 59 footballers, diarrhoea in 55.6% on one 10 g dose against 28.6% on two 5 g doses17 | Strong for the gain; moderate for the stomach rates, from one trial |
| For adults over 55 who do resistance training, the register's second sentence, with its training conditions (see seniors above) | A higher creatinine reading on a kidney blood test, with measured filtration unchanged, across 12 pooled trials13 | Register wording; strong |
| A small memory effect in pooled trials, largest in adults aged 66 to 76 (standardised effect 0.29)8 | No cognition claim is authorised in the UK; the committee refused one in 202415 | Disputed: a published letter alleges double-counting in the memory analysis;18 the refusal is a matter of record |
Nothing on the right-hand side is a reason to avoid creatine in a healthy adult; each is a reason to take 3 to 5 g a day, split if your stomach objects, and to tell your GP you take it before a blood test.
Side effects and safety, briefly
About a kilogram of water weight; an upset stomach if you take too much at once; a raised creatinine reading on blood tests that is a measurement effect, not kidney damage. Kidney and liver harm, hair loss, cramps and dehydration have been tested and not found in healthy adults.3, 10, 13 The hair loss question is answered here and what happens when you stop is here. The practical questions have their own pages: does creatine cause bloating, does creatine dehydrate you, can you put creatine in coffee or tea, is creatine safe for teenagers, can you take creatine while pregnant or breastfeeding, and creatine vs creatinine for the blood-test reading.
What we don't know
- Creatine without exercise in older adults, for strength or muscle. The trials that tested it found no change; the evidence is with training.
- Pregnancy. No supplement trial has reported; one is registered.
- Long-term use above 5 g a day. Multi-year data is at 3 to 5 g.
Frequently asked questions
Does creatine give you energy?
Not in the way coffee does. Creatine is not a stimulant; it refills phosphocreatine, the store muscle uses to regenerate energy in the first seconds of a hard effort.3 The authorised UK wording is that creatine increases physical performance in successive bursts of short-term, high intensity exercise, at 3 g a day; drink normally alongside it, as no water target is evidenced. Energy-reserve and energy-boost wordings were refused.
Does creatine help with recovery?
One supplier-funded trial of 14 untrained men found greater recovery of knee-extension strength after muscle-damaging exercise on creatine, and the 2017 position stand lists recovery among the areas studied.3, 19 That is a small record, reported as a finding, not a claim.
Who should take creatine?
Adults doing high-intensity or resistance training, which is the register's condition for the performance wording. Vegetarians and vegans, who start with lower stores.1 Adults over 55 who lift: the register's second sentence applies to them, provided the training is regular, progressive and at least three times a week. Who should ask first: anyone with kidney disease, anyone pregnant or breastfeeding, anyone under 18, and anyone on regular medicines. Creatine side effects has the detail, with separate guides on whether creatine is safe for teenagers and on creatine while pregnant or breastfeeding.
Sources
- Ostojic SM. The evolving role of creatine in public health: from food-based nutrient to supplement and beyond. Public Health Nutrition, 2025. PubMed 41243431.
- Hultman E, Söderlund K, Timmons JA, Cederblad G, Greenhaff PL. Muscle creatine loading in men. Journal of Applied Physiology, 1996. PubMed 8828669.
- Kreider RB, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition, 2017. PubMed 28615996.
- Zhang H, et al. Effects of creatine supplementation on muscle strength gains: a meta-analysis and systematic review. PeerJ, 2025. PubMed 41328071.
- Ashtary-Larky D, et al. Creatine supplementation and resistance training: a comparison between novice and experienced lifters. A systematic review and dose-response meta-analysis. Journal of the International Society of Sports Nutrition, 2025. PubMed 41433021.
- Desai I, et al. The effect of creatine supplementation on resistance training-based changes to body composition: a systematic review and meta-analysis. Journal of Strength and Conditioning Research, 2024. PubMed 39074168.
- Pashayee-Khamene F, et al. Creatine supplementation protocols with or without training interventions on body composition: a GRADE-assessed systematic review and dose-response meta-analysis. Journal of the International Society of Sports Nutrition, 2024. PubMed 39042054.
- 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. PubMed 35984306.
- Xu C, Bi S, Zhang W, Luo L. The effects of creatine supplementation on cognitive function in adults: a systematic review and meta-analysis. Frontiers in Nutrition, 2024. PubMed 39070254.
- Antonio J, et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? Journal of the International Society of Sports Nutrition, 2021. PubMed 33557850.
- Chilibeck PD, Kaviani M, Candow DG, Zello GA. Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis. Open Access Journal of Sports Medicine, 2017. PubMed 29138605.
- Forbes SC, Candow DG, Ostojic SM, Roberts MD, Chilibeck PD. Meta-analysis examining the importance of creatine ingestion strategies on lean tissue mass and strength in older adults. Nutrients, 2021. PubMed 34199420.
- Effect of creatine supplementation on kidney function: a systematic review and meta-analysis. BMC Nephrology, 2025. PubMed 41199218.
- Sales LP, et al. Creatine supplementation (3 g/d) and bone health in older women: a 2-year, randomized, placebo-controlled trial. Journals of Gerontology Series A, 2020. PubMed 31257405.
- UK Nutrition and Health Claims Committee. Scientific opinion 004 on creatine and cognitive function. gov.uk, published 14 August 2024. UKNHCC scientific opinion, gov.uk.
- Brooks SJ, et al. Creatine monohydrate supplementation changes total body water and DXA lean mass estimates in female collegiate dancers. Journal of the International Society of Sports Nutrition, 2023. Randomised trial, 13 women (7 on creatine), 42 days; one supplier-linked author. PubMed 36960692.
- Ostojic SM, Ahmetovic Z. Gastrointestinal distress after creatine supplementation in athletes: are side effects dose dependent? Research in Sports Medicine, 2008. PubMed 18373286.
- Eckert I, et al. Letter to the editor: double-counting due to inadequate statistics leads to false-positive findings in "Effects of creatine supplementation on memory in healthy individuals". Nutrition Reviews, 2023. PubMed 36644917.
- Cooke MB, et al. Creatine supplementation enhances muscle force recovery after eccentrically-induced muscle damage in healthy individuals. Journal of the International Society of Sports Nutrition, 2009. Randomised trial, 14 men; supplier-funded. PubMed 19490606.
This article is general information, not medical advice. If you have a medical condition or take regular medication, check with your GP or pharmacist before starting creatine.
