Creatine: the one supplement with unambiguous evidence

Creatine monohydrate is the most-studied sports supplement in existence, with hundreds of trials across decades. The findings are consistent enough that it is one of the few things in this field where confident statements are justified.

What it does

Creatine is stored in muscle as phosphocreatine, which donates a phosphate group to rapidly regenerate ATP during short, high-intensity efforts. Supplementing increases muscle creatine stores, typically by twenty to forty percent depending on starting levels.

The practical effect is a modest improvement in performance in repeated high-intensity efforts — more reps at a given load, slightly better recovery between sets, and over time somewhat greater strength and muscle gains than training alone.

The effect size is real and moderate. It is not transformative and it does not replace training. It is roughly the difference between a good year and a slightly better one.

The dosing, which is simple

Around three to five grams a day, every day, indefinitely. That is the entire protocol.

The loading phase — around twenty grams a day for five to seven days — saturates the muscle faster, reaching full stores in under a week rather than in three or four. It is optional. If you are not in a hurry, skip it; loading causes gastrointestinal discomfort in a fair number of people.

Timing is irrelevant. Take it whenever you will remember. The muscle store is what matters and it takes weeks to change meaningfully, so daily consistency is the only variable.

Cycling off is unnecessary. There is no evidence that continuous use downregulates anything problematic, and stopping simply lets stores fall back over several weeks.

The form

Monohydrate. That is the recommendation and it has not changed in decades.

The alternative forms — hydrochloride, ethyl ester, buffered versions, liquid preparations — are marketed on claims of better absorption or fewer side effects. None have shown superiority over monohydrate in head-to-head comparisons, several have shown inferiority, and all cost more.

Buy the cheapest reputable micronised monohydrate you can find. Look for a product with third-party testing if you compete under anti-doping rules, since contamination in the supplement industry is a genuine risk.

The concerns, addressed

Kidney damage. The most persistent myth. It arises because creatine supplementation raises serum creatinine, which is a marker used to assess kidney function — so a routine blood test can look abnormal without anything being wrong. Studies in healthy people, including long-term ones, have not shown kidney harm. People with existing kidney disease should discuss it with a doctor.

Hair loss. This comes from a single small study that found an increase in a hormone associated with hair loss, in a small group of rugby players, over a short period. It has not been replicated and no study has actually measured hair loss. The evidence for this concern is extremely thin.

Water retention. Real, and mostly intracellular — water drawn into the muscle rather than under the skin. Expect a small increase in scale weight in the first weeks. It is not fat and it is not bloating in the usual sense, though a minority of people do report feeling puffy.

Cramping and dehydration. The evidence points the other way if anything; studies in athletes training in heat have not found increased cramping or heat illness.

Who responds

Not everyone. Around a fifth to a third of people are non-responders, generally because their baseline muscle creatine is already high — often people who eat a lot of red meat and fish, which are the dietary sources.

Conversely, vegetarians and vegans typically have lower baseline stores and tend to show larger responses.

If you have taken it consistently for a couple of months and noticed nothing, you may simply be a non-responder. That is a legitimate reason to stop.

The other applications

Interest has expanded well beyond muscle. There is a growing body of work on creatine and cognitive function, particularly under stress, sleep deprivation or in vegetarians, and some early work in older adults on muscle preservation and bone.

These areas are less settled than the performance findings. Treat them as promising rather than established.

The honest framing

Creatine is cheap, safe for healthy people, well-evidenced, and modest in effect. That combination makes it the only supplement most lifters need to think about, alongside filling actual nutritional gaps.

It is also worth noting what it does not do: it will not compensate for inadequate protein, insufficient sleep, or a programme that is not progressing. The supplement conversation only becomes worthwhile once those are handled, and by then it is a short conversation.