Creatine: does it work, and how to take it

The short answer

Creatine monohydrate is the single best-evidenced performance supplement available — full stop. With Grade A evidence across multiple meta-analyses for strength, power and lean muscle mass, it is the rare supplement where the science and the real-world results align completely. The verdict: Worth it, for almost anyone who lifts.

What creatine is

Creatine is a naturally occurring compound synthesised in the liver and kidneys from the amino acids arginine, glycine and methionine. Your muscles store it as phosphocreatine — a rapid-fire energy substrate that regenerates ATP during short, high-intensity efforts: sprints, heavy sets, explosive jumps.

You get creatine from meat and fish (roughly 1–2 g per 500 g of red meat), but vegetarians, vegans and people eating less meat typically have 20–30% lower baseline muscle creatine stores. That gap is exactly where supplementation earns its keep.

Does it work? The evidence

Strength and power — Grade A

This is creatine's headline achievement. Pooled data from multiple randomised controlled trials and meta-analyses consistently show creatine supplementation increases maximal strength and power output when combined with resistance training. The 2017 International Society of Sports Nutrition (ISSN) position stand — the field's most comprehensive review — concluded creatine monohydrate is the most effective ergogenic nutritional supplement available for improving high-intensity exercise and lean body mass. A 2025 meta-analysis published in a PubMed-indexed journal (PMC12430374) confirmed strength and power gains at the 3–5 g/day dose, with effect sizes that are meaningful in the gym, not just in a lab. Gains of 5–15% in strength benchmarks over 4–12 weeks are typical in well-designed trials.

Lean muscle mass — Grade A

Creatine does not build muscle on its own — training builds muscle; creatine lets you do more training at a higher intensity, which drives the adaptation. But the downstream effect on lean mass is real, consistent and graded A. In vegetarians and vegans, the effect is often larger because of the lower dietary baseline. Adults over 50 also show meaningful responses, making creatine one of the most practical tools for preserving muscle as we age. If you are on a muscle growth programme or even body recomposition, creatine is the one supplement worth building into the plan.

Cognition and fatigue — Grade C

Emerging research suggests creatine may support cognitive performance — particularly under sleep deprivation and mental fatigue — because the brain is a significant ATP consumer. The evidence is early and limited (Grade C), but intriguing. Do not buy creatine for brain benefits alone; buy it for the muscles and treat any cognitive upside as a bonus.

How to take it

Dose

3–5 g of creatine monohydrate per day is the effective, evidence-backed range. At 70 kg, 3 g is adequate; larger athletes benefit from the upper end.

Loading phase (optional): 20 g/day split into four 5 g doses for 5–7 days saturates your muscle stores in roughly a week. Without loading, the same saturation is reached in 3–4 weeks at the maintenance dose. Neither outcome nor total effect size differs between protocols — loading only speeds the timeline. Given the minor GI risk of large single doses, many people skip it and take 3–5 g daily from day one.

Use our creatine dosage calculator to find your personal maintenance dose based on bodyweight.

Form

Creatine monohydrate is the only form with Grade A evidence. Creatine HCl, ethyl ester, buffered creatine (Kre-Alkalyn) and various "next-generation" forms are marketed at a significant premium with no body of evidence to justify the price. The ISSN position stand is explicit: monohydrate is the reference standard.

Look for Creapure (German-manufactured, purity >99.9%) or an Informed-Sport certified product to ensure no banned-substance contamination.

Timing

Consistency beats timing. Take it at the same time daily — with breakfast, in a post-workout shake, with dinner. The minor post-workout advantage seen in some studies is not robust enough to reorganise your day around. If you are also using caffeine pre-workout, the two can be taken together without issue.

Who should take creatine — and who should not

Take it if you:

• Lift weights and want more strength or muscle
• Are vegetarian or vegan (lower dietary baseline)
• Are over 50 and want to preserve power and lean mass
• Are involved in explosive or high-intensity sport (athletic performance, sprinting, CrossFit, team sport)

Hold off or check with a GP if you:

• Have diagnosed kidney disease — creatine increases creatinine (a kidney marker), which can confuse blood tests and may not be appropriate for compromised kidneys
• Are pregnant or breastfeeding — insufficient data
• Are under 18 — though generally considered safe, evidence in younger adolescents is thinner

For the vast majority of healthy adults, creatine is one of the most risk-free supplements you can take.

Safety and interactions

Creatine has been studied more rigorously than almost any other sports supplement, and the safety record at 3–5 g/day in healthy adults is exceptional. There is no credible evidence of kidney or liver harm at this dose across decades of research.

Early water weight: expect roughly 1 kg on the scale in the first 1–2 weeks. Creatine draws water into muscle cells — this is intracellular, not bloating, and it is part of how creatine works. It is not fat.

GI tolerance: large single doses (e.g. 20 g in one hit during loading) can cause cramping or loose stools. Splitting into ≤5 g doses and using micronised monohydrate resolves this for most people.

Kidney markers: creatine raises serum creatinine slightly, which is a harmless metabolic by-product — not kidney damage. Inform your GP if you are supplementing and having routine bloods.

No meaningful interactions with common medications at standard doses. If you are on immunosuppressants or have kidney disease, get medical clearance first.

How to buy creatine well

Creatine monohydrate powder is one of the cheapest effective supplements available — typically £10–20 for a 500 g tub (roughly 100–166 days at 3–5 g/day). Premium forms cost 5–10× more for no measurable benefit.

What to look for:

• Creapure certification (the gold standard for purity — manufactured in Germany by AlzChem)
• Informed-Sport tested (batch-tested for banned substances — essential for competitive athletes)
• Simple, unflavoured powder — no proprietary blends or added stimulants

Avoid products with "creatine matrix" or proprietary blends that obscure individual doses. You cannot verify what you are actually getting.

The verdict

Creatine monohydrate earns its Grade A and its Worth it verdict because the evidence is overwhelming, the safety profile is excellent, the cost is negligible and the effect is real and repeatable. If you are lifting consistently and not taking creatine, you are leaving performance on the table.

That said — supplements are roughly 5% of your results. The other 95% comes from your training programme, nutrition, sleep and consistency. Creatine stacked on top of an inconsistent plan does very little. Creatine stacked on top of a structured, coached approach compounds the gains.

If you want to build muscle, lose fat, or simply get stronger — book a free consultation and let's get the full plan right. Or start with the free Physique Blueprint quiz to see exactly where you are and what your next move should be.