The overall safety picture
Creatine monohydrate has been studied in clinical trials for over 30 years at doses ranging from 3g to 20g per day, in populations from adolescents to elderly adults, for durations from days to years. The consistent finding is that it is safe for healthy individuals at recommended doses.
International bodies including the International Society of Sports Nutrition have published position statements concluding that creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes and is safe for use in healthy adults.
Does creatine damage the kidneys?
This is the most persistent creatine myth. It originates partly from the fact that creatine supplementation raises creatinine levels in blood — creatinine is a metabolic byproduct of creatine breakdown. Elevated blood creatinine is one clinical marker used to assess kidney function, so the association looked concerning to early observers.
However, creatinine from creatine supplementation is a different context from elevated creatinine caused by kidney disease. Multiple studies in healthy individuals have found no adverse effect on kidney function from long-term creatine supplementation. The International Society of Sports Nutrition specifically states that creatine does not cause kidney damage in healthy people.
The caveat: people with pre-existing kidney disease should consult a doctor before supplementing, as impaired kidneys may handle creatine metabolism differently.
Does creatine cause hair loss?
This claim stems from a single 2009 study on rugby players that found creatine supplementation raised levels of dihydrotestosterone (DHT) — a hormone associated with male pattern hair loss. The study measured DHT, not actual hair loss, in a small cohort.
No subsequent study has replicated the DHT finding. No study has demonstrated a direct link between creatine supplementation and accelerated hair loss in humans. If you are genetically predisposed to male pattern baldness and DHT is a known trigger, some caution is reasonable given the single DHT study — but the claim that creatine causes hair loss is not established by the available evidence.
Does creatine cause dehydration and cramping?
Creatine draws water into muscle cells, which led to a hypothesis that it might increase dehydration risk or muscle cramping — particularly in hot conditions. This concern was largely based on theoretical reasoning rather than empirical evidence.
Multiple studies in athletes exercising in heat have found no increase in cramping, dehydration or heat-related illness from creatine supplementation compared to placebo. Some research has found the opposite — creatine may slightly improve thermoregulation by increasing intracellular water.
Weight gain from creatine
Creatine causes an increase in scale weight of approximately 1–2kg when supplementation begins, particularly with a loading phase. This is water drawn into muscle cells and is not fat gain.
This temporary weight increase is often misinterpreted as fat or unwanted mass. For weight-class athletes or those monitoring weight carefully, it is worth being aware of. The water weight is not harmful and partially reverses when supplementation stops.
Who should be cautious
People with pre-existing kidney conditions should get medical advice before supplementing. Those with a personal or family history of polycystic kidney disease in particular should approach with caution.
Pregnant and breastfeeding women are typically advised to avoid creatine supplementation as a precaution, since data in these populations is limited. Anyone on medication that affects kidney function should consult a doctor.
For healthy adults with normal kidney function, the safety profile of creatine at 3–5g per day is well established across decades of research.