Creatine is one of the most studied supplements in the world: more than thirty years of research, hundreds of clinical trials, and an official position from the International Society of Sports Nutrition. This does not prevent the question of its dangers from coming up in every conversation. Here's what the data shows, effect by effect.
In short. At usual doses and in healthy individuals, no serious adverse effects have been reported, including with continuous intake for up to five years. The discomforts observed are digestive, related to excessively high single doses or poorly dissolved powder. Cases where medical advice is needed are specific and listed below.
Kidneys
This is the most widespread concern, and it has an identifiable origin: an isolated case published in 1998, concerning a patient who already suffered from pre-existing kidney disease.
Since then, the issue has been studied in depth. In individuals with healthy kidneys and at usual doses, more than thirty years of work have not shown kidney damage2.
There is, however, a practical point worth knowing, and which almost no one mentions: creatine slightly elevates blood creatinine, the marker used to assess kidney function. This increase reflects supplementation, not damage to the organ. If you have a blood test, report it — it avoids a false alarm and a useless assessment.
The question is not whether creatine is dangerous, but for whom it requires medical advice.
Liver
Same pattern, less noise. Liver parameters have been monitored in numerous trials, including over long periods, with no reported alterations in healthy individuals2.
Digestive issues
This is the only truly common side effect, and it is almost always avoidable.
Two causes. An excessively large single dose — this is the classic problem of the loading phase, around 20g per day. And insufficiently dissolved powder, which reaches the stomach in particle form.
The correction can be summarized in one sentence: 3 to 5g well-dissolved in a large glass of water, and no loading phase2. Regular daily intake fills muscle reserves in three to four weeks, without discomfort.
Water retention and weight gain
A gain of 0.5 to 1.5 kg is possible in the first few days. This corresponds to water retained inside the muscle fiber, and lean mass.
In trials lasting from one week to two years, creatine does not increase fat mass1,3. And since the water mobilized is intramuscular and not subcutaneous, this is not the mechanism that produces the bloated appearance.
Cramps and dehydration
The idea has circulated since the nineties. The data goes the other way: fewer cramps and fewer heat-related incidents in supplemented individuals, not more2.
Hair loss
No study has reported actual hair loss in humans3.
The idea is based on a single study, published in 2009 involving rugby players, which observed an increase in a hormone — DHT — that remained within normal values. No hair measurements were taken. The study was never replicated. Seventeen years later, it still fuels entire forums.
Doping
Creatine is not on any list of banned substances. It has nothing in common with a steroid: it is a molecule that the body produces itself, at a rate of about one gram per day, and which is found in meat and fish.
The real risk: product quality
This is the topic never discussed, yet it's the only one that should cause concern.
Food supplements are not subject to market authorization. The responsibility for compliance rests with the manufacturer. Poorly produced creatine can contain synthesis impurities—dicyandiamide, dihydrotriazine—or heavy metals.
What distinguishes a reliable product is therefore not its marketing, but its traceability: the origin of the raw material, and the existence of a batch analysis certificate, carried out by an accredited independent laboratory. A brand that cannot provide this does not know what it is selling.
When to consult a doctor
The situations are specific, and there's no need to broaden them.
Known kidney disease. The decision should be made with your doctor, not by reading a brand page.
Current medical treatment. Same logic, and this applies to any dietary supplement.
Pregnancy and breastfeeding. Research is encouraging but insufficient. This is an individual decision, to be made with a healthcare professional.
Outside of these cases, in a healthy individual and at documented doses, the safety profile of creatine is one of the best established among dietary supplements.
Aplomb is creatine monohydrate in 5g single-dose sticks. One active ingredient, one pre-weighed dose, nothing more to do than open the stick.
To learn more: creatine for women · creatine and menopause · the 19 most frequent questions
References
- Smith-Ryan AE, Cabre HE, Eckerson JM, Candow DG. Creatine Supplementation in Women's Health: A Lifespan Perspective. Nutrients 2021;13(3):877.
- Kreider RB et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr 2017;14:18.
- Antonio J et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? J Int Soc Sports Nutr 2021;18:13.
Article written by Virginie Mauran. This information is general and does not replace individual medical advice.