The Ultimate Guide to Creatine

I got a message from a client last week that I recognise immediately. She had been given creatine by her partner, bought the tub, opened it, and then put it in the back of the cupboard. "I am nervous about taking it," she wrote. "My doctor once told me it was hard on the kidneys. But I also keep reading that it is the most researched supplement there is. I genuinely do not know what to believe."

I know that feeling. And after years of advising clients at my private practice, at Google DeepMind through the Kyros Project, and at The Wellness Clinic at Harrods, I have given the same reassurance so many times I could say it in my sleep. The science on creatine is unusually clear. The myths around it are unusually persistent. This guide sets both straight.

Every claim here is checked against the primary research - the ISSN position stand, the UKNHCC scientific opinion, and recent PubMed meta-analyses - not supplement marketing. And I will cover the one thing most creatine explainers skip: what it actually means for women.

Creatine is a compound your body makes naturally, mostly in the liver and kidneys, from three amino acids: arginine, glycine, and methionine. Your muscles store it as phosphocreatine, and that stored form is the fuel your body draws on first during short, explosive efforts - a sprint, a heavy lift, the last few reps of a set.

The mechanism is straightforward. When your muscles work at high intensity, they burn through ATP (adenosine triphosphate), the molecule that powers muscular contraction. ATP is exhausted within about 10 seconds. Phosphocreatine donates a phosphate group to regenerate ATP faster, extending the window before your output drops. More creatine in the muscle means more phosphocreatine available, which means you can sustain peak effort slightly longer.

Your body produces around 1-2 grams of creatine per day, and you get another gram or two from meat and fish - red meat and salmon are the richest dietary sources. But your muscle stores are typically only 60-80 per cent saturated. Supplementing with 3-5 grams of creatine monohydrate per day brings those stores to full saturation. That extra capacity is why the research consistently shows improvements in strength, power, and lean muscle mass.

The compound was identified by the French chemist Michel Eugène Chevreul in 1832. It has been studied continuously since the 1990s. No other sports supplement has this depth of evidence behind it. The International Society of Sports Nutrition calls it "the most effective ergogenic nutritional supplement currently available to athletes."

The evidence base for creatine divides into four areas. I will take them in order of how well-established each is.

Strength and power. This is where the research is most consistent. Across dozens of randomised controlled trials, creatine supplementation produces meaningful gains in maximal strength, peak power output, and the ability to repeat high-intensity efforts. Meta-analyses typically find increases of 5-15 per cent in short-duration, high-intensity exercise performance compared to placebo.

Muscle growth and body composition. Creatine does not build muscle on its own - training does that. What creatine does is support the cellular conditions that allow muscle protein synthesis to occur: improved hydration in muscle cells, faster recovery between sets, and the ability to push harder in the sessions that drive adaptation. Over 6-12 weeks of combined supplementation and resistance training, studies consistently show greater lean muscle gains than training alone.

Brain function and cognition. This area is developing, and the regulatory position is more cautious than the supplement industry suggests. The UK Nutrition and Health Claims Committee's (UKNHCC) scientific opinion on creatine and cognitive function concluded that a cause-and-effect relationship has not been established between creatine supplementation at 3g per day or less and improved cognitive function - only one of the ten studies reviewed met inclusion criteria, and that study showed no difference versus placebo. The brain is an energy-hungry organ, and the biological rationale is plausible: the same ATP-regenerating mechanism that supports muscle performance also supports neurons. Emerging research, particularly in populations under cognitive stress or sleep deprivation, and in vegetarians and vegans (whose baseline brain creatine is lower), continues to explore this. But the UKNHCC's assessment is the current regulatory position, and it is a negative one - the evidence has not yet met the bar for a substantiated claim.

Menopause and women's health. A 2025 review published in PMC on creatine in women's health highlighted benefits across the hormonal lifespan: improvements in bone density, lean mass preservation, and mood in peri- and post-menopausal women. Oestrogen interacts with the creatine transport system, which may partly explain why women's responses to supplementation appear to be hormonally influenced. This is an emerging area, but the direction of evidence is consistent and worth taking seriously.

Let me be direct about this, because it is the question I hear most often and the answer is clearer than the anxiety around it suggests.

In healthy adults, creatine at 3-5 grams per day does not damage the kidneys. That conclusion comes from a 2025 meta-analysis of controlled trials published in PMC, reviewing creatine's effect on kidney function. The studies consistently show no adverse changes in markers of renal function - glomerular filtration rate, creatinine clearance, or kidney morphology - in people without pre-existing kidney disease.

The confusion comes from a lab value. Creatine supplementation raises serum creatinine - a waste product of creatine metabolism that kidneys filter out. Creatinine is routinely used as a marker of kidney function in blood tests, and a raised level normally suggests the kidneys are under strain. When a doctor sees a raised creatinine in a patient who supplements with creatine, the reflexive concern is understandable. But the mechanism is different: the rise is from increased creatine turnover, not from kidney impairment. Kidney filtration rate itself does not change.

The important caveat: if you have existing kidney disease, or a history of it, speak to your doctor before supplementing. Creatine is not contraindicated for everyone with any kidney history, but it does require individualised assessment. For healthy adults with no kidney issues, the long-term safety data is robust. The ISSN position stand, which reviewed trials spanning up to five years of continuous use, found no adverse effects.

I want to be honest about this, because most creatine guides either deny it or bury it. Creatine genuinely does pull water into your muscle cells, and the scale will move.

When you saturate your muscle creatine stores, water follows. Muscle cells are more osmotically active with higher intracellular creatine, so they draw in fluid from circulation. In the first 1-2 weeks of supplementation - and particularly if you do a loading phase - you can expect a 1-2 kilogram rise on the scales. This is intramuscular water. Your muscles are more hydrated. Your gut is not bloated. You have not gained fat.

This matters, because if no one tells you that the scale is going to move, you will quit at exactly the wrong moment. You are two weeks in, seeing real results building, and you panic and stop. I have watched clients do this more than once.

The practical way to avoid the most dramatic version of this: skip the loading phase. A maintenance dose of 3-5 grams per day reaches full saturation in 3-4 weeks rather than one week. The water weight still accumulates, but gradually, and without the 1-2 kilogram jump in a single week that the 20-gram loading phase can produce.

One more thing: the water weight is not permanent. If you stop supplementing, muscle creatine levels return to baseline over 4-6 weeks, and the intramuscular water leaves with it. Your actual lean muscle mass - built by training - remains.

Creatine has a perception problem. Most of the early research was conducted on male athletes, and the marketing followed - the 5-kilogram tubs in gym-adjacent shops, the sponsorships with powerlifters. The science, though, does not make creatine a gendered supplement.

Women typically have lower baseline muscle creatine stores than men (about 70-80 per cent of male stores on average, due to lower muscle mass). This means the relative benefit from supplementation is at least as large, and in some contexts - particularly for cognitive effects and during perimenopause - the benefit may be larger.

The 2025 women's health review found improvements across several domains specifically relevant to women: sarcopenia prevention in older women, mood stabilisation in the premenstrual and perimenopausal periods (creatine appears to support serotonin production), and bone health via improvements in bone mineral density. None of these findings are definitive yet - this is an active research area - but the direction is consistent enough to recommend creatine confidently for women in the same terms as men.

The "will I get bulky" concern deserves a direct answer. Creatine does not cause bulking. It causes water retention in muscle tissue (see above) and, over months of training, supports greater muscle hypertrophy than training alone. Whether you build visible muscle bulk depends almost entirely on your training volume and caloric intake - and for most women lifting at moderate intensity, creatine supports strength and body composition improvement without size outcomes they do not want.

The standard maintenance dose is 3-5 grams per day, every day. Body size does not meaningfully change the effective dose for most people - the 3-5g range covers the vast majority of adults, from lighter women to larger men.

Loading phase: optional. A loading protocol (typically 20 grams per day, divided into 4x5g doses, for 5-7 days) saturates your muscle stores in about a week. The end state is identical to simply taking 3-5g daily for 3-4 weeks. Loading just gets you there faster. It also tends to produce more pronounced initial water retention and, in some people, mild gastrointestinal discomfort from the higher single doses.

My recommendation for most people: skip the loading phase. Start with 3-5 grams per day and give it four weeks. The difference in long-term outcomes is negligible, and you avoid the early scale jump and digestive discomfort.

Timing: does not matter much. Daily consistency is the only variable that matters for maintaining saturation. Evidence slightly favours post-workout on training days (one meta-analysis found marginally greater strength gains with post-workout timing), but the effect is small. On rest days, take it whenever. With food or without food - it is absorbed well either way, although some people find it easier on the stomach with a meal.

Creatine cycling: not necessary. You do not need to come off creatine periodically. Your body does not stop producing its own creatine endogenously, and there is no evidence of tolerance developing. The research includes trials of continuous use up to five years with no adverse effects.

This section is deliberately short, because the choice is genuinely simple and the supplement industry makes it look harder than it is.

Start with creatine monohydrate. It is the most-studied form, the cheapest per dose, and the form used in virtually all the research cited in this guide. Creatine monohydrate is the evidence base. The rest are variations. Creatine monohydrate versus HCL, buffered creatine (Kre-Alkalyn), creatine ethyl ester: these alternatives are consistently priced 2-4x higher, and no well-controlled trial has demonstrated superior performance outcomes compared to monohydrate at the same dose.

One thing worth looking for: Creapure certification. Creapure is a purity standard for creatine monohydrate manufactured by AlzChem in Germany, tested for heavy metals and contaminants, and used in most of the research literature. Brands like Huel, Naked Nutrition, and some Bulk lines use Creapure-certified creatine. It is not strictly necessary - non-Creapure monohydrate can be perfectly clean - but if purity matters to you (and for supplements, it should), Creapure is a verifiable standard rather than a marketing claim.

Cheap monohydrate is not inferior to expensive monohydrate, but the flavoured, 'advanced' blends at triple the price often hide an under-dose behind proprietary blend labelling. Check the label: you are looking for 3-5 grams of creatine monohydrate per serving. If the label shows a 'proprietary blend' without breakdown, or if creatine is listed alongside six other ingredients in a 'performance matrix', you cannot verify the dose. Buy pure monohydrate instead.

For people who want a practical starting point in the UK: Myprotein's unflavoured monohydrate and Bulk's Pure Creatine Monohydrate are both competitively priced, widely available, and straightforward products. Form Nutrition and Huel offer Creapure options at a premium for those who want the certified version.

Many people combine their creatine with coffee in the morning - it mixes well with a large latte or dissolves in water alongside your mushroom coffee routine if you already take adaptogens. There is no interaction between caffeine and creatine at normal doses, and your morning coffee is as good a vehicle as any. If you are already thinking about the quality of what goes into your cup, healthy coffee beans from clean-sourced roasters are worth exploring for the same reason you are reading this guide.

Cooking destroys a portion of creatine content. These are approximate raw values. Supplementation provides a more reliable and consistent dose than dietary sources alone.