Creatine monohydrate

What it is

Creatine is a compound your body makes from amino acids and also gets from meat and fish. About 95 percent of it is stored in muscle, mostly as phosphocreatine, a quick energy reserve.

Creatine monohydrate is the standard supplement form. People take it to support strength, power and muscle gain from resistance training, and more recently for brain energy and ageing muscle.

It is one of the few supplements where the evidence is genuinely strong, and it is cheap compared with most.

How it works

Extra creatine tops up phosphocreatine stores in muscle. That helps regenerate ATP, the cell energy currency, during short bursts of hard effort, so you can often squeeze out slightly more work per session. It also pulls water into muscle cells.

What the evidence says

• Strong Strength and power in resistance training
  Many trials show modest but consistent gains in repetitions, power and strength when combined with training.
• Strong Lean body mass
  Part of the early gain is water held in muscle, but over months it supports greater muscle gain alongside training.
• Strong Repeated sprint and high-intensity performance
  Helps short bursts; it does little for pure endurance events.
• Moderate Muscle and function in older adults
  Appears to add a small benefit when paired with resistance exercise.
• Limited Cognition, especially when sleep-deprived or vegetarian
  Early results are interesting but small and inconsistent in healthy people.

Evidence ratings are our plain-English summary of how much good human research exists, not a promise of results. How we rate evidence.

Dosage and timing

• Maintenance: 3 to 5 g daily is the usual approach. Larger people sometimes use up to around 0.1 g per kg of body weight.
• Loading is optional: about 20 g a day split into 4 doses for 5 to 7 days, then 3 to 5 g daily. It gets you there faster but can upset the stomach.
• Take it every day, including rest days. Cycling off is not needed for effect.
• Drink normal amounts of fluid. Check current guidance if you have any kidney concerns.

Forms and what to look for

• Creatine monohydrate is the best studied and cheapest. Choose it first.
• Micronised monohydrate dissolves better and is fine if you dislike gritty powder.
• Creatine HCl, buffered creatine and ethyl ester are sold as better, but there is no convincing evidence they beat monohydrate and they cost more.
• Look for a label that says creatine monohydrate (often Creapure) with no proprietary blend.

What to expect, and when

• You are unlikely to feel it on day one. Expect a 1 to 2 kg scale rise in the first weeks, mostly water.
• Training performance changes tend to show over 4 to 8 weeks of consistent use with resistance training.

Side effects

• Water retention and a small weight increase early on.
• Stomach upset or bloating, mostly with large single doses or loading.
• Muscle cramping is commonly blamed but is not well supported in studies.
• Raises blood creatinine, a marker used to assess kidneys, without necessarily meaning kidney damage. Tell any clinician you take it.

Interactions

• Caffeine: mixed evidence on whether it blunts the effect; most people use both.
• Medicines that can affect the kidneys, such as NSAIDs at high doses or some diuretics: check with a pharmacist.
• Other supplements that alter kidney function markers can make lab results harder to read.

Who should avoid it

• Anyone with kidney disease or reduced kidney function should speak to a clinician first.
• Pregnant or breastfeeding people: not enough safety data, so check with a clinician.
• Under 18s: not generally recommended without advice.
• Anyone with an upcoming kidney blood test should mention it.

Risks and safety

• Creatine is not banned by WADA, but sports bodies usually advise testing for contamination in any supplement.
• Safety in healthy adults at standard doses looks good over several years, but very long-term data in some groups is limited.
• Poor-quality products can be contaminated or under-dosed.

Buying well: quality and testing

• Look for Informed Sport or similar batch testing if you compete.
• Plain creatine monohydrate with a single ingredient is the safest choice.
• Be wary of multi-ingredient pre-workouts that hide creatine dose in a proprietary blend.
• Cheap powder is usually fine; price differences mostly reflect brand and flavour.

Bottom line

If you lift or do repeated high-intensity training and want one supplement with real evidence behind it, this is the one. A steady 3 to 5 g a day, cheap monohydrate, and patience is all it takes. It is less useful for endurance athletes or anyone not training.