Creatine has been studied for decades, and the headline is reassuring: for healthy adults at normal doses, it is one of the safest supplements available. Most of the fears attached to it, kidney damage, hair loss, cramping, do not hold up to the evidence. Here is the honest breakdown of what is real, what is myth, and who genuinely needs to be careful.
The short answer
For healthy adults, creatine monohydrate at 3 to 5 grams a day is considered safe for ongoing use. The International Society of Sports Nutrition concluded that supplementation up to 30 grams a day for as long as five years is safe and well tolerated in healthy people (Kreider et al., 2017). The main caveats are specific groups, covered below, who should check with a doctor first.
What the evidence says about kidneys
This is the most common worry, so it is worth being precise. A systematic review and meta-analysis pooling trials of creatine and kidney function concluded that supplementation "does not induce renal damage" and did not meaningfully change serum creatinine or urea in the doses and durations studied (de Souza e Silva et al., 2019).
Longer-term data point the same way. In a placebo-controlled trial, people taking 10 grams a day for about ten months showed no significant rise in kidney markers and no meaningful increase in adverse effects (Groeneveld et al., 2005).
One source of confusion is worth clearing up. Creatinine, a marker doctors use to estimate kidney function, is a natural byproduct of creatine. Taking creatine can nudge it up slightly on a blood test without any actual kidney damage. If you have labs done, tell your doctor you take creatine so the result is read in context.
The real side effects
Creatine is not entirely free of effects. The genuine ones are mild.
- A little water weight. Most people gain roughly half a kilo to two kilos early on. This is water held inside the muscle, not fat, and it reverses if you stop.
- Occasional stomach upset. Bloating, gas, or loose stools can happen, almost always with large single doses or aggressive loading. Dropping to 3 to 5 grams a day, or splitting the dose, usually fixes it.
That is essentially the list for healthy users.
The myths worth retiring
Cramping and dehydration
The belief that creatine causes cramps or dehydration is not supported. Controlled and cohort studies have not found higher rates of cramping, dehydration, or heat illness in people who take it (Antonio et al., 2021). If anything, creatine pulls water into the muscle rather than out of the body.
Hair loss
This is the myth that worries people most, so here is exactly where it comes from. The entire scare traces to a single 2009 study in 20 college rugby players. It found that creatine raised the ratio of DHT (a hormone linked to hair loss) to testosterone by about 36% over three weeks (van der Merwe et al., 2009).
Two things matter here. First, that study never measured hair loss at all, only a hormone ratio. Second, no study since has replicated even the hormone finding. A detailed review of the wider evidence concluded that creatine does not increase testosterone or DHT and does not cause hair loss (Antonio et al., 2021). In short, one small study that did not look at hair has been stretched into a widespread belief the evidence does not support.
Who should be careful
Creatine's strong safety record applies to healthy people. Talk to a doctor before taking it if you:
- have existing kidney disease or a history of kidney problems,
- are pregnant or breastfeeding (it simply has not been well studied here),
- or take medications that affect the kidneys, such as certain long-term anti-inflammatories or diuretics.
This is about sensible caution, not a sign that creatine is dangerous for these groups; it is that the evidence base is built on healthy adults.
Do you need lab monitoring?
For most healthy people with no risk factors, routine blood tests are not necessary just because you take creatine. If you have any kidney risk factors, the sensible path is a baseline check of kidney function and a conversation with your doctor before starting, rather than testing on your own.
The bottom line
For healthy adults, creatine is well-studied, well-tolerated, and low-risk at sensible doses. The kidney and hair-loss fears are not backed by evidence, the real side effects are minor, and the people who should pause and ask a doctor are a clearly defined few. For how much to take, see our creatine dosage guide; for the full picture, our complete creatine guide and creatine for women, or browse all our nutrition guides.
Frequently Asked Questions
Is creatine safe for daily use? For most healthy adults, yes. Taken at 3 to 5 grams a day, creatine has a strong safety record across decades of research. Check with a doctor if you have kidney disease or take regular medication.
Does creatine damage your kidneys? In healthy people at recommended doses, the evidence does not show kidney damage. A meta-analysis found no harmful change in kidney markers. People with existing kidney disease should ask a doctor first.
Does creatine cause hair loss? There is no good evidence that it does. The idea traces to a single 2009 study that measured a hormone ratio, not hair, and has not been replicated.
Does creatine cause cramps or dehydration? No. Controlled studies have not found higher rates of cramping, dehydration, or heat illness in people who take creatine.
Why does creatine raise my creatinine on a blood test? Creatinine is a normal byproduct of creatine. A small rise can show up on a test without meaning any kidney damage, but tell your doctor you take it so results are read correctly.
Medical disclaimer: This article is for informational purposes only. Always consult a qualified healthcare provider before making changes to your health routine.
Sources
- Kreider RB, 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, 2017 — PubMed. https://pubmed.ncbi.nlm.nih.gov/28615996/
- Antonio J, et al. Common questions and misconceptions about creatine supplementation: what does the scientific evidence really show? Journal of the International Society of Sports Nutrition, 2021 — PubMed Central. https://pmc.ncbi.nlm.nih.gov/articles/PMC7871530/
- de Souza e Silva A, et al. Effects of creatine supplementation on renal function: a systematic review and meta-analysis. Journal of Renal Nutrition, 2019 — PubMed. https://pubmed.ncbi.nlm.nih.gov/31375416/
- van der Merwe J, Brooks NE, Myburgh KH. Three weeks of creatine monohydrate supplementation affects dihydrotestosterone to testosterone ratio in college-aged rugby players. Clinical Journal of Sport Medicine, 2009 — PubMed. https://pubmed.ncbi.nlm.nih.gov/19741313/
- Groeneveld GJ, et al. Few adverse effects of long-term creatine supplementation in a placebo-controlled trial. International Journal of Sports Medicine, 2005 — PubMed. https://pubmed.ncbi.nlm.nih.gov/15795816/
All sources accessed 31 May 2026.
