Creatine: what the evidence backs and what it doesn't

The question we get about creatine is rarely whether it works. It is how much it actually does, and for what. The answer is unusually tidy for a supplement: one part of the story rests on very solid ground, a second part is plausible but unfinished, and a third part is marketing riding on the reputation of the first.

Here is where those lines sit.

What we know reliably

Creatine sits in muscle as a fast top-up system for regenerating energy during short, hard efforts — roughly the first five to thirty seconds of maximal work. Supplementing fills that store to its ceiling, and a full store means you can do slightly more before the effort falls apart. The evidence here is consistent and has been repeated for decades, across different groups and different tests.

The effect is real but moderate. On average it comes out as a few per cent more on short maximal efforts, and often one or two extra reps in sets lasting up to half a minute. Modest on any single day, but it adds up to noticeably more total work over a training block.

More work done, with enough food and sleep, means somewhat more muscle than you would have built without it. The order matters: creatine does not build muscle by itself, it lets you train slightly harder, and the training builds the muscle. Take the training away and the effect on body composition is close to nothing.

Dosing is a settled question. Three to five grams of creatine monohydrate a day, every day including rest days, saturates the muscle in three to four weeks. If you are impatient, twenty grams a day split into four doses for five to seven days gets you there in a week, after which you drop back to three to five grams.

Monohydrate is the only form that has been properly studied. There is no evidence the pricier versions work better, and for some of them no good evidence they raise muscle creatine as reliably at all. The gap in price is far larger than any gap in effect.

A gain of one to two kilos on the scale in the first few weeks is expected, and it is mostly water pulled into the muscle cell rather than fat. In healthy adults, years of use at these doses has not been linked to kidney or liver damage — one of the better-examined safety questions in the whole supplement aisle.

Last solid point: responses vary. People who eat little meat or fish start with lower stores and tend to notice the most, while a fair share of people are already near their ceiling and barely feel a thing.

What is likely but not settled

The brain is the interesting open front. The signal is clearest when the brain is under stress — after a broken night's sleep or a long stretch of mental load — while results in well-rested healthy people are all over the place. Something is probably there, but the dose, the duration and who benefits are unresolved.

In older adults doing resistance training, the evidence leans positive for muscle mass and function, though it is weaker and messier than in younger athletes. Creatine is the addition, not the foundation, and the foundation is still a sensibly built strength programme after fifty. For bone, the evidence is thin so far and not worth building expectations on.

Recovery and soreness: mixed. Some findings point to less muscle damage and a quicker return of strength, others show nothing at all. This one is poorly resolved and should not be your reason for buying creatine.

Scaling the dose to body weight, around 0.05 to 0.1 grams per kilo, makes sense for very large people but is tested far less than the flat five grams. The same caveat applies to whether women need a different approach — the data so far says no, but there is much less of it.

What gets repeated wrongly

Cramps and dehydration. The most stubborn myth of the lot, and the evidence runs against it. When cramping and heat tolerance are actually measured, creatine either does nothing or helps slightly.

Hair loss. The entire scare rests on one isolated hormonal finding that was never reliably repeated and that never measured hair in the first place. That is not proof creatine bothers nobody, but it is a long way from an established link.

Kidneys and blood tests. Creatine raises blood creatinine because creatinine is its breakdown product. A higher reading in someone taking creatine is not the same thing as impaired kidney function, though it causes needless alarm if your doctor does not know you are on it.

Timing. Before training, after, or in the evening barely matters. Creatine works by saturating the muscle over weeks, so day-to-day consistency is the only timing variable that changes the outcome.

Cycling on and off. There is no reason for four-week breaks and similar schemes. Your body does not stop responding, and levels simply hold while you keep taking it.

Creatine as a fix for everything. It is not a steroid or a hormone, it does little for long endurance work, and it has nothing to do with injury prevention. Knees and shoulders need sane loading and progression instead, which is what we covered in the pieces on knee injury prevention and what actually protects the shoulder in the gym.

What this means for your training and diet

• Take monohydrate, three to five grams daily, on training and rest days alike.
• For a faster start, seven days at twenty grams split into four doses, then back down to five.
• If it upsets your stomach, split the dose and take it with a meal.
• Expect a kilo or two on the scale in the first two to four weeks, and do not read it as fat gain.
• Drink water normally; there is no special hydration protocol.

What creatine will not do is cover the rest of the job. If your protein sits below roughly 1.6 to 2.2 grams per kilo of body weight, or your training does not progress from week to week, no powder rescues the programme. It is the last few per cent, not the first fifty.

In a calorie deficit it still earns its place, because it helps you hold on to strength while you lose fat. As a complete beginner you will make progress without it, but it does no harm then either.

When to see a doctor

Speak to a doctor before starting if you have kidney or liver disease, a single kidney, diabetes, blood pressure treated with medication, or if you are pregnant or breastfeeding. The same goes for anyone under eighteen.

If you are having blood taken, mention that you use creatine so the creatinine result is read correctly. Swollen legs, flank pain, a marked change in urination or persistent nausea are not expected reactions and warrant an appointment.

In short

• Well established: monohydrate, three to five grams a day, a small but reliable gain in strength and reps, and a good safety record in healthy adults.
• Likely: benefit for a tired brain, benefit for older lifters who train, possibly something for recovery.
• Unproven or plain wrong: cramps, dehydration, kidney damage in healthy people, the need to cycle, the expensive forms.
• Creatine is a cheap, sensible add-on to good training and good food. Nothing more, and nothing less.