For healthy adults, creatine monohydrate is one of the safest and most researched supplements available, and the serious side effects people worry about, kidney damage and hair loss, are not supported by controlled studies. The genuine effects are minor and easy to manage. Here is what the evidence shows on each concern.
Key takeaways
- Creatine monohydrate is backed by more than 500 studies and a strong safety record at recommended doses.
- The scary claims, kidney damage and hair loss, are not supported by controlled research.
- Real effects are minor: a little water weight, and stomach upset only from large single doses.
Creatine is one of the most studied supplements in the world
Few sports supplements have been examined as closely as creatine monohydrate. More than 500 peer-reviewed studies have looked at how it works and whether it is safe.1 After decades of research, the conclusion is consistent. The International Society of Sports Nutrition states that there is no compelling evidence that short- or long-term creatine use, at doses up to 30 grams a day for five years, causes any harmful effect in healthy people or in clinical populations.2
Despite that record, creatine still attracts questions about hair loss, kidney damage, bloating, weight gain and stomach problems. This guide works through each concern and explains what the science actually shows. Where a claim is a myth, we say so. Where a side effect is real but manageable, we explain how to avoid it.
The side effects that are actually established
At recommended doses, the reported side effects of creatine are minor. The most consistent one is a small increase in body weight during the first week, which comes from water drawn into muscle rather than fat.3 The other is occasional digestive discomfort, which is linked to taking a large amount at once rather than to creatine itself.4
The International Society of Sports Nutrition also found no evidence that creatine increases the commonly cited problems of dehydration, muscle cramping or musculoskeletal injury.2 Mayo Clinic describes creatine as likely safe for many people when taken at recommended doses for up to five years.5
Does creatine damage your kidneys?
This is the most persistent myth. Creatine can raise a blood marker called creatinine, and because doctors use creatinine to estimate kidney function, a higher reading can look alarming. In reality, creatinine is simply the breakdown product of creatine, so more creatine in the muscle means more creatinine in the blood. It is an expected metabolic byproduct, not a sign of damage.1
Controlled studies in people with healthy kidneys have not found that creatine harms kidney function.1,6 A 2023 review in Nutrients concluded that clinical trials do not support the claim that creatine causes kidney failure.7 The sensible caution is for people who already have kidney disease, who should speak to their doctor first. You can read the full detail in our guide to creatine and your kidneys.
Does creatine cause hair loss?
The hair loss worry traces back to a single 2009 study in rugby players that measured a rise in the hormone DHT.8 That study never measured hair at all, and no study has reproduced the DHT finding since. In 2025, the first randomised controlled trial to measure both DHT and actual hair health over 12 weeks found no effect on either.9 The full evidence is covered in our article on whether creatine causes hair loss.
Does creatine make you gain weight or look bloated?
Creatine can cause a small, rapid rise in body weight when you start, typically one to three kilograms, and this is water held inside the muscle rather than fat.3 Creatine contains no calories and does not increase fat mass.3 Any early puffiness or bloating is usually tied to the high-dose loading phase and fades within a few weeks.10 Taking a steady 3 to 5 grams a day instead of loading reduces it.3,10 See our detailed guides on whether creatine makes you gain weight and creatine and bloating.
Does creatine upset your stomach?
Digestive complaints almost always come from taking too much at once. In a controlled trial, a single 10 gram dose caused diarrhoea in far more athletes than the same 10 grams split into two smaller doses.4 Splitting your dose, taking it with food and using a well-dissolved micronised powder keeps the gut comfortable. We cover this in our guides to creatine and constipation and creatine, diarrhoea and stomach problems, along with creatine, thirst and urination.
How to take creatine safely
The evidence points to a simple routine. You can load with about 20 grams a day, split into four 5 gram servings, for five to seven days, then move to 3 to 5 grams a day.2 Or you can skip loading and take 3 to 5 grams a day from the start, which reaches the same muscle saturation over three to four weeks with less initial water weight.2,3 Choosing a pure, micronised product helps it dissolve fully and sit well in the stomach. Our Pure Micronised Creatine Sachets are single-serving micronised sachets designed for exactly this.
The bottom line
Creatine monohydrate has one of the strongest safety records of any supplement in nutrition science. The serious concerns that circulate online, kidney damage and hair loss, are not supported by controlled research. The genuine effects, a little water weight and occasional stomach upset from large single doses, are mild and easy to manage. For healthy adults, creatine is a well-studied and well-tolerated supplement.
Related reading
Frequently asked questions
Is creatine bad for you?
No. Across more than 500 studies, creatine monohydrate has shown a strong safety profile in healthy people at recommended doses.1,2 The main effect is a small amount of water weight.
How much creatine is safe per day?
Research supports 3 to 5 grams a day for maintenance. Doses up to 30 grams a day have been studied for up to five years without harm in healthy people.2
Who should not take creatine?
People with existing kidney disease, liver disease or who are pregnant or breastfeeding should speak to a healthcare professional first.5,11
This article is for general information and is not medical advice. If you have a health condition or take medication, speak to your doctor before starting any supplement.
References
- Antonio, J. et al. Common questions and misconceptions about creatine supplementation. Journal of the International Society of Sports Nutrition 18, 13 (2021). Journal of the International Society of Sports Nutrition
- Kreider, R. B. et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition 14, 18 (2017). Journal of the International Society of Sports Nutrition
- Antonio, J. et al. Common questions and misconceptions about creatine supplementation. JISSN 18, 13 (2021). JISSN
- Ostojic, S. M. & Ahmetovic, Z. Gastrointestinal distress after creatine supplementation in athletes: are side effects dose dependent? Research in Sports Medicine 16, 15-22 (2008). National Library of Medicine
- Mayo Clinic. Creatine. Mayo Clinic
- de Souza e Silva, A. et al. Effects of Creatine Supplementation on Renal Function: A Systematic Review and Meta-Analysis. Journal of Renal Nutrition 29, 480-489 (2019). National Library of Medicine
- Longobardi, I. et al. Is It Time for a Requiem for Creatine Supplementation-Induced Kidney Failure? A Narrative Review. Nutrients 15, 1466 (2023). National Library of Medicine
- van der Merwe, J., Brooks, N. E. & Myburgh, K. H. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clinical Journal of Sport Medicine 19, 399-404 (2009). National Library of Medicine
- Lak, M. et al. Does creatine cause hair loss? A 12-week randomized controlled trial. Journal of the International Society of Sports Nutrition 22 (2025). JISSN
- Healthline. Does Creatine Cause Bloating? (medically reviewed). Healthline
- Cleveland Clinic. Creatine: benefits, supplements and safety. Cleveland Clinic
