Creatine
monohydrate

If you follow a vegan or vegetarian diet, your muscle stores are probably lower than those of someone omnivorous, which makes the response to supplementation more noticeable.

A 70 kg man stores about 120 grams of creatine in his body, most of it (approximately 95%) in the muscles. Women, having less muscle mass, store a significantly lower amount, although recommended supplementation doses are almost the same. About 1–2% of that reserve is degraded each day, equivalent to about 2 grams. The body replenishes this loss in two ways: synthesizing between 1 and 1.7 grams per day in the liver, kidneys, and pancreas, and obtaining an additional 0.25 to 1 gram through diet.

Creatine was not invented by anyone in a sports lab. It was discovered in 1832 by the French chemist Michel Eugène Chevreul while he was analyzing meat extracts — in fact, its name comes from the Greek kreas, meaning meat. For more than a century it was just a fact of biochemistry with no practical application. The first study to show that taking it orally raised muscle stores was published in 1992. Two years later, several athletes who had used it at the Barcelona Olympic Games spoke openly about it. It has not stopped being studied since, and today it is one of the sports supplements with the most published clinical trials.

Creatine does one main thing: it helps your muscles recover energy faster during short, intense efforts. In studies, that translates into more repetitions before reaching failure, more power in sprints and faster recovery between sets. However, it does not work the same for everyone: some people barely respond.

It is not a stimulant, it does not increase heart rate, it does not burn fat.

Every time your muscles contract they need energy in the form of ATP — the body’s energy currency. The problem is that ATP stores last only a few seconds. To replenish them quickly, the body uses the phosphocreatine stored in the muscle: creatine kinase catalyzes a reaction that transfers a phosphate group from phosphocreatine to ADP, regenerating ATP almost instantly.

It is an energy buffer — a reserve your body uses in the first seconds of any maximal effort. Phosphocreatine stores are depleted in about 10 seconds of maximal effort and need 3 to 5 minutes to recover fully. Supplementing with creatine raises those stores by up to 20% above baseline, which means more fuel available for every set, every sprint, every jump.

There is more: creatine also promotes intracellular hydration — it increases the water inside muscle cells, which activates anabolic signals that favor protein synthesis. The water it “retains” is not subcutaneous water that causes visible swelling, but intracellular water that contributes to real muscle volume.

For anyone who does strength training or any sport with intense, repeated efforts: weights, CrossFit, interval cycling, soccer, padel, swimming. It is also useful for runners who include intervals and for anyone who wants to improve their performance in the gym.

Some studies indicate that it also helps recovery after training, so that the following sets and the sessions on later days suffer less.

It does not improve pure aerobic endurance: no benefit is expected in a marathon at a steady pace. Where its effect has been seen is in high-intensity efforts with pauses between them.

Creatine is not only for athletes. In older adults, combined with strength training, it has shown benefits for preserving muscle mass and strength with age. On cognition the evidence is less consolidated: there are favorable results under sleep deprivation, but in healthy, rested people the effect has not been clear.

You have two equally valid options:

Without a loading phase — 3 to 5 grams per day (around 3 g if you weigh 60 kg, around 4–5 g if you weigh 80 kg or more). Muscle stores saturate in about 4 weeks. It is the most convenient option and the one the stomach tolerates best.

With a loading phase — 20 grams per day split into 4 doses for 5 to 7 days, followed by 3 to 5 grams as maintenance. Stores saturate in a week. According to the reference study, the two regimens reach the same level but at different speeds.

Some studies suggest that taking it close to training, before or after, is slightly better than at another time of day. What counts most is taking it every day, whether you train or not.

The proposed explanation is that exercise increases insulin sensitivity, and that favors muscle uptake of creatine; that is why a slight advantage is attributed to taking it after training.

On caffeine: a 1996 study suggested it could cancel out creatine’s ergogenic effect. Later reviews have qualified this — co-ingestion does not prevent muscle saturation, but it may blunt some acute effect. In practice, taking coffee pre-workout and creatine post-workout is a reasonable solution if you want to be cautious.

With carbohydrates. In a classic study, adding about 90 g of simple carbohydrates to each dose during the loading phase increased muscle retention by 60% compared with taking it alone. The proposed mechanism: fast carbohydrates produce an insulin spike, and this hormone helps creatine enter the muscle cells. There are alternatives with less sugar: a combination of 50 g of carbohydrates and 50 g of protein produced a similar effect.

The market offers many forms of creatine. The short answer: no, they are not the same, and the difference matters.

According to the official position of the ISSN, no form has demonstrated greater efficacy than monohydrate.

A seal is not essential, but it adds external verification. There are two types.

Creapure® is not an independent seal, but the raw-material brand of a specific manufacturer. According to its manufacturer, it guarantees ≥99.9% purity.

Informed Sport or NSF Certified for Sport — on the finished product. They test batch by batch to detect banned substances. Relevant if you compete in sports with anti-doping testing.

If you compete under anti-doping testing, the relevant seal is the one on the finished product (Informed Sport or NSF), because it is the one that screens for banned substances; it can be combined with a certified raw material. If you do not compete, that seal matters less.

A selection of the most cited and highest-quality studies (randomized, placebo, double- or triple-blind), carried out in humans. Two exceptions, flagged on their cards: Hultman, for historical reasons, and Xie. The link to the study is in the advanced level.

Strength and hypertrophy

Endurance and repeated efforts

Health and longevity

Cognition

Safety

Non-responders. Between 20 and 30% show little or no response. The most likely explanation is that they already have high baseline levels of muscle creatine — common in heavy red-meat eaters.

Optimal dose in women. Women have endogenous stores 70–80% lower than men. The menstrual cycle, estrogens and menopause modify the kinetics, but specific studies are scarce.

Very long-term effects. Safety up to five years in healthy people is well documented. Beyond that, the data are scarce.

Creatine and cancer. We know of no completed study in people designed to measure whether creatine, on its own, changes the risk or the course of a cancer. What exists points in different directions: the signal in mice from Xie 2026; a single study we located that associated muscle-building supplements, mixtures in which creatine cannot be isolated, with more testicular cancer; and surveys in which people who ate more creatine with meat and fish reported less cancer, without measuring supplements. The trials in patients with cancer were designed to measure muscle and strength.

Optimal dose for cognitive effects. The brain has local creatine synthesis and slower uptake than muscle. Sustained cognitive effects might require higher doses, or high acute doses in specific situations of mental stress.

Creatine monohydrate has the strongest evidence profile of any sports supplement — the conclusion of the ISSN official position of 2017, ratified in 2021 and 2024, and supported by more than 500 clinical trials. In strength, hypertrophy and repeated high-intensity efforts, the signal is robust, consistent and reproducible.

That said, there are structural limitations we should be aware of.

On study size. The typical n is 10 to 60 participants. The effects are large and consistent, which lends credibility, but extrapolation to very diverse populations requires caution.

On conflicts of interest. Kreider, Candow, Forbes and Smith-Ryan have declared ties with AlzChem or other companies in the sector. This does not invalidate their methodology, generally sound, but it is information the critical reader deserves to have.

On cognition. The clearest effects appear under conditions of acute energy stress or in populations with a baseline deficit. The hypothesis of cognitive improvement in healthy, well-nourished young people remains unproven in any robust way.

On the real gaps. As of May 2026 we have not located any double-blind RCT in mild cognitive impairment or in Alzheimer’s, nor any RCTs directly comparing the two dosing protocols by measuring muscle saturation. Safety data in healthy people beyond five years are scarce.

On creatine and cancer. The testicular cancer study (Li et al., 2015; case-control) measured mixtures of creatine, protein or androstenedione, without adjusting for anabolic steroids; its authors point out that around 15% of the non-hormonal supplements analyzed in another study contained them without declaring it. The analyses of the NHANES survey are cross-sectional, and their authors acknowledge possible reverse causation: people who have had cancer are advised to reduce red meat. The 2025 safety review that considers the cancer risk unsupported predates Xie 2026; two of its four authors declare ties to a creatine manufacturer, which paid for the publication. A registered trial in metastatic prostate cancer (CREATINE-52) plans to measure markers of progression.

On thrombosis. Xie 2026 did not measure thrombotic events. There are isolated published cases in young people who were taking creatine, at least three with other documented risk factors. In an analysis of adverse events reported in published trials, whose authors declare ties to a creatine manufacturer, very few trials reported thromboembolic events or tumors, with no differences from placebo; these data allow neither asserting nor ruling out a risk.

For a healthy adult who trains, the evidence is among the strongest in sports supplementation. For cognitive or clinical applications there are signals, but they require more research.

Creatine is one of the supplements with the best documented safety profile. That said, consult your doctor before taking it if:

An important nuance: creatine raises blood creatinine as a normal byproduct of its metabolism. If you have a blood test while taking it, that value will appear elevated without it meaning renal damage. Inform your doctor before interpreting that result.

There is no clinical evidence establishing a contraindication in cancer. The authors of Xie 2026 are of the opinion that creatine cannot simply be recommended to patients with cancer, an opinion based mainly on mice. With an active cancer or one under treatment, the decision rests with the oncologist.