Creatine monohydrate

What is Creatine monohydrate?

Creatine is a compound your body makes and eats every day. The liver and kidneys build it from three amino acids — arginine, glycine and methionine — at a rate of about a gram a day, and a diet that includes meat and fish supplies roughly another gram. About 95 per cent of the body's creatine is stored in skeletal muscle, much of it as phosphocreatine. A small, steady amount breaks down each day into creatinine, which the kidneys clear, so the store has to be topped up continuously.

Creatine monohydrate is creatine bound to one molecule of water, and it is the form used in almost all of the research. It is about 88 per cent creatine by weight, so a 5 g scoop gives about 4.4 g of creatine itself. Supplements are made synthetically rather than from animal products, which makes them suitable for vegetarians and vegans. "Micronised" creatine monohydrate is the same substance milled into finer particles so it mixes more easily; it is not a different or stronger form. Creapure is a trade name for creatine monohydrate from one German manufacturer.

Vegetarians and vegans get almost no creatine from food and tend to have lower muscle stores. That is why they often see a larger rise in muscle creatine when they supplement.

How it works

Muscles run on ATP, and during an all-out effort they use it faster than they can make it. Phosphocreatine is the fastest backup: it hands its phosphate to ADP to rebuild ATP almost instantly, which powers the first few seconds of a sprint, a jump or a heavy set. It runs out quickly, and how much you have limits how hard you can go and how fast you recover between efforts.

Supplementing raises the total creatine in muscle by about 20 per cent, as the chart below shows. With more phosphocreatine on hand, you can squeeze out a rep or two more per set, or hold sprint speed a little longer across repeats. Over weeks of training, that extra work is what builds the additional strength and muscle. Creatine also draws water into muscle cells, which accounts for the early gain on the scales and may itself be a signal for growth.

How much you respond depends on where you start. People whose muscle creatine is already high — often those who eat a lot of meat and fish — gain the least, and some barely respond at all. The brain uses creatine too, but its levels rise much less than muscle's at ordinary doses, which is why most brain studies use far larger amounts.

What the research actually shows

Evidence strength varies by what is being claimed, so each use is graded separately against the published criteria rather than averaged into one reassuring letter.

Effective dosage

For most adults, 3 to 5 g of creatine monohydrate a day, every day, is the whole protocol. Timing matters much less than consistency: the benefit comes from keeping your muscle stores full, not from when you take each scoop. Take it with water, juice, a shake or a meal — whatever makes it a daily habit.

A loading phase is optional. About 20 g a day, split into four 5 g doses, for five to seven days fills muscle in about a week; 3 g a day gets to the same level in about four weeks. The classic Nottingham study by Hultman and colleagues showed both routes end in the same place, and that 2 g a day was enough to hold the level after loading. Loading is useful if you want the effect quickly, for example before a competition. Otherwise it costs more, uses up a tub faster and is more likely to cause stomach upset.

If you stop, muscle creatine falls back to its starting level over roughly a month. Brain studies have used much larger doses, such as 20 g a day for a week or a single dose of about 0.35 g per kilogram; those are research protocols, not daily advice.

Where products diverge from the research. Most creatine powders get the dose right, with a 3 g or 5 g scoop. The gaps are elsewhere.

Serving sizes vary: some powders suggest a scoop larger than the 3 g the claims are based on, which simply makes a tub run out sooner. Pre-workout blends often contain 1 to 2 g — below the studied amount — alongside caffeine you may not want every day. Mass gainers sometimes include 3 g per serving, which is fine as long as you take the full serving and do not also take creatine separately.

Newer formats deserve the most caution. Creatine breaks down into creatinine in heat and moisture, and gummies are made with both. In 2024, the supplement maker NOW Foods tested 12 creatine gummy products and found five failed: two contained only a fraction of the creatine on the label and three contained none. Plain powder is the cheapest and most reliable way to get a known dose.

Alternative forms — creatine hydrochloride, ethyl ester and "buffered" creatine — are often sold at smaller doses with claims of better absorption. There is no good evidence for those claims. In head-to-head trials, creatine ethyl ester raised muscle creatine less than monohydrate, and a buffered form did no better.

Safety, side effects and interactions

Creatine monohydrate is one of the most thoroughly studied supplements for safety. At the recommended doses, reviews by the International Society of Sports Nutrition find no harm in healthy people, including in trials lasting years. A 2019 meta-analysis of the kidney studies found no change in blood creatinine or urea in healthy people taking creatine. In the US, the FDA had no questions about a notice that creatine monohydrate is generally recognised as safe for use in foods.

There is one thing to tell your doctor. Because creatine breaks down into creatinine, supplements can nudge blood creatinine up, and a standard kidney blood test (eGFR) can then look slightly worse without any kidney damage. Mention that you take creatine before a blood test.

Ask a doctor first if you have kidney disease or diabetes that affects your kidneys, or take medicines that can strain the kidneys, such as regular high-dose anti-inflammatory painkillers. There is not enough research on creatine in pregnancy or breastfeeding, so avoid it then unless your doctor advises otherwise. Research in teenagers is more limited than in adults; talk to a doctor or sports dietitian first.

The common side effects are mild: early weight gain from water, and stomach upset or loose stools with large single doses — which is why loading doses are split through the day. The worries about cramps and dehydration have not held up in trials.

Hair loss is the best-known myth. It traces to one 2009 study in 20 rugby players, in which the hormone DHT rose after a week of loading. No study has shown creatine causes hair loss, and a 2025 randomised trial of 5 g a day for 12 weeks found no change in DHT, hair density, hair thickness or follicle health.

Creatine is not banned in sport. As with any supplement, products can be contaminated, so competitive athletes should choose ones batch-tested by a scheme such as Informed Sport or NSF Certified for Sport.

None of this is medical advice. See the medical disclaimer for what that means before you act on anything here.