The Scientific Consensus on Creatine Safety
Creatine monohydrate has been studied more extensively than almost any other sports supplement. With over 500 peer-reviewed studies and more than 30 years of research, we have an unusually clear picture of its safety profile. The scientific consensus, as stated by the International Society of Sports Nutrition, is that creatine monohydrate is "extremely safe" for healthy individuals.
This doesn't mean creatine is free of all effects—it means the effects are well-documented, predictable, and benign for the vast majority of users. Let's examine the evidence for each major safety concern.
Creatine and Kidney Function
The most persistent myth about creatine is that it damages kidneys. This concern arose because creatine supplementation increases creatinine levels in blood tests—a marker doctors use to assess kidney function. However, this increase is an expected consequence of having more creatine in your system, not a sign of kidney damage.
To understand why, consider how creatinine is produced: it's a breakdown product of creatine and phosphocreatine in muscle. More creatine means more creatinine—it's simple chemistry, not pathology.
Key Kidney Studies
Poortmans & Francaux (1999)
Examined kidney function in athletes taking creatine for up to 5 years. Found no negative effects on glomerular filtration rate (GFR) or tubular reabsorption.
Medicine & Science in Sports & Exercise
Lugaresi et al. (2013)
Studied creatine supplementation in individuals with only one kidney. After 12 weeks of supplementation at 20g/day (loading) then 5g/day, no adverse effects on kidney function were observed.
European Journal of Applied Physiology
Gualano et al. (2008)
Case study of a man with one kidney who took creatine for 35 days. Kidney function remained stable throughout and after the study period.
Applied Physiology, Nutrition, and Metabolism
The evidence is clear: in healthy individuals, creatine does not impair kidney function. However, people with pre-existing kidney disease should consult their nephrologist before using creatine, as their kidneys may have reduced capacity to process the additional metabolites.
Creatine and Liver Health
Concerns about liver toxicity are even less supported than kidney concerns. The liver is involved in creatine metabolism, but no studies have found that creatine supplementation causes liver damage or elevates liver enzymes beyond normal ranges.
Liver Safety Evidence
Kreider et al. (2003)
21-month study in athletes taking 5-20g creatine daily. Comprehensive blood panels showed no changes in liver enzymes (AST, ALT, GGT) or bilirubin levels.
Mayhew et al. (2002)
Long-term football player study. Athletes taking creatine for 0.25 to 5.6 years showed no difference in liver function markers compared to non-users.
The only population that should be cautious is those with pre-existing liver conditions. For everyone else, the evidence suggests creatine is entirely safe for hepatic function.
The Dehydration and Cramping Myth
Perhaps no creatine myth is more pervasive than the idea that it causes dehydration and muscle cramps. This belief likely originated from early observations that creatine draws water into muscle cells, leading to speculation that it might dehydrate other tissues.
The research tells a completely different story. Not only does creatine not cause dehydration—it appears to improve hydration status and may reduce cramping.
Hydration Research
Dalbo et al. (2008) - Systematic Review
Reviewed all available literature and found "no evidence that creatine supplementation impairs thermoregulation or increases the incidence of musculoskeletal injuries, dehydration, muscle cramping, or gastrointestinal upset."
Lopez et al. (2009)
Three-year study of college football players. Creatine users had significantly fewer incidents of dehydration, muscle cramps, and heat-related illnesses compared to non-users.
Greenwood et al. (2003)
NCAA Division I football players using creatine had fewer muscle cramps, heat illness/dehydration, muscle strains, and total injuries than non-creatine users.
The mechanism actually makes sense when you think about it: creatine increases total body water, which improves hydration capacity. The water drawn into muscles is still available for thermoregulation. If anything, creatine appears to be protective against heat-related issues.
Creatine and Hair Loss: The DHT Question
This is the one area where we can't give creatine a clean bill of health—not because it's proven harmful, but because there's genuine uncertainty. A single 2009 study by van der Merwe et al. found that creatine supplementation increased dihydrotestosterone (DHT) levels by 56% after a loading phase.
DHT is the hormone primarily responsible for androgenic alopecia (male pattern baldness) in genetically susceptible individuals. If creatine genuinely and consistently increases DHT, it could theoretically accelerate hair loss in those already prone to it.
What We Know About Creatine and DHT
- 1.One study (van der Merwe, 2009) found DHT increased by 56% after creatine loading in rugby players
- 2.This study has never been replicated, despite attempts
- 3.Other studies measuring testosterone and DHT haven't found the same effect
- 4.There's a plausible mechanism (creatine may increase 5-alpha reductase activity)
- 5.Anecdotal reports of hair loss exist, but anecdotes are unreliable
The honest answer is: we don't know for certain. If you're already losing your hair or have a strong family history of male pattern baldness, this uncertainty is worth considering. If hair loss isn't a concern or you're not genetically predisposed, the single unreplicated study probably isn't reason enough to avoid creatine.
Long-Term Safety Data
One of creatine's strongest safety arguments is the duration of study. We have long-term data that simply doesn't exist for most supplements:
| Study | Duration | Participants | Finding |
|---|---|---|---|
| Poortmans & Francaux | 5 years | Athletes | No kidney damage |
| Mayhew et al. | Up to 5.6 years | Football players | No adverse markers |
| Kreider et al. | 21 months | 98 athletes | Comprehensive safety |
| Bender et al. | 2 years | Parkinson's patients | Well tolerated |
Safety in Special Populations
Adolescents
The American College of Sports Medicine previously discouraged creatine use in those under 18, but this was based on lack of data rather than evidence of harm. More recent studies in adolescent athletes have found creatine to be safe, and the ISSN position stand notes there's no scientific evidence that short- or long-term creatine supplementation has detrimental effects in younger populations.
Older Adults
Research in older adults (60+) is particularly promising. Multiple studies have found creatine supplementation combined with resistance training improves muscle mass, strength, and functional capacity more than training alone—with no safety concerns. Given the natural decline in muscle creatine levels with age, supplementation may be even more beneficial for this population.
Women
Creatine research has historically focused on men, but available studies in women show similar safety profiles. There's no evidence that women experience different or additional side effects. The same dosing protocols apply.
What Major Organizations Say
International Society of Sports Nutrition (2017)
"Creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes in terms of increasing high-intensity exercise capacity and lean body mass during training... There is no compelling scientific evidence that the short- or long-term use of creatine monohydrate has any detrimental effects on otherwise healthy individuals."
American College of Sports Medicine
Recognizes creatine as one of the few supplements with genuine ergogenic effects, with a well-established safety profile.
European Food Safety Authority (EFSA)
Has approved health claims for creatine regarding enhanced physical performance during short-term, high-intensity, repeated exercise bouts.
Frequently Asked Questions
Can creatine cause stomach issues?
Some people experience mild GI discomfort, usually during loading phases with high doses (20g/day). Taking creatine with food, splitting doses throughout the day, or skipping the loading phase typically resolves this. Creatine monohydrate is the gentlest form.
Does creatine cause water retention/bloating?
Creatine does increase water content in muscles (intracellular), which may add 2-4 lbs of scale weight. This isn't subcutaneous bloating—it actually makes muscles appear fuller. This water weight is inside muscle cells where you want it.
Is creatine a steroid?
No. Creatine is a naturally occurring compound found in meat and fish, and your body produces it from amino acids. It has no hormonal effects and is not related to anabolic steroids. It's legal everywhere and not banned in any sports.
Do I need to cycle creatine?
No. Unlike some supplements, creatine doesn't require cycling. Long-term continuous use is safe and maintains benefits. Your body doesn't develop tolerance to creatine.
What about creatine and drug interactions?
Creatine has few known drug interactions. However, because it's processed by the kidneys, those taking nephrotoxic medications or with kidney disease should consult their doctor. NSAIDs combined with creatine may theoretically increase kidney stress, though this hasn't been proven problematic.
The Bottom Line
After reviewing decades of research, the conclusion is clear: creatine monohydrate is remarkably safe for healthy individuals. The kidney damage myth is thoroughly debunked. The dehydration myth is not just wrong—creatine may actually improve hydration. Liver function is unaffected.
The only area of genuine uncertainty is the potential effect on DHT and hair loss, which deserves more research but is based on a single unreplicated study. For those already prone to hair loss, this may warrant caution; for others, it's probably not a significant concern.
If you're a healthy adult considering creatine, the scientific evidence strongly supports that it's safe. Stick with creatine monohydrate (the most studied form), use standard dosing (3-5g daily), and you can expect the benefits without meaningful health risks.