Is Creatine Safe? What 500+ Studies Over 30 Years Tell Us

Creatine monohydrate is the single most studied sports supplement in history. Since the early 1990s, when creatine entered mainstream athletic use following the Barcelona Olympics, researchers have produced over 500 peer-reviewed papers examining its effects on the human body. The question of safety has been addressed repeatedly, from multiple angles, across diverse populations. The accumulated evidence is unambiguous.

The International Society of Sports Nutrition (ISSN), the American College of Sports Medicine, and the European Food Safety Authority have all reviewed the creatine literature. Their consensus: creatine monohydrate, when used at established doses, is safe for healthy individuals. This article walks through the evidence supporting that position and addresses the caveats that responsible science demands.

The Scope of the Evidence Base

Understanding creatine safety requires appreciating the sheer volume of research. Kreider et al. published a landmark review in 2017 in the Journal of the International Society of Sports Nutrition, analyzing data accumulated over two decades. Their review encompassed studies in athletes, sedentary individuals, children, elderly populations, and clinical patients. The consistent finding across these diverse groups was that creatine monohydrate at recommended doses (3-5 g/day for maintenance, or 20 g/day during a 5-7 day loading phase) produced no clinically significant adverse effects.

Persky and Brazeau (2001), writing in Pharmacological Reviews, conducted one of the earliest comprehensive safety analyses. They reviewed creatine's pharmacokinetics, metabolic pathways, and reported side effects. Their conclusion noted that the compound's safety profile was well-characterized and that reported adverse events were overwhelmingly anecdotal rather than clinically documented.

The ISSN Position Stand on creatine supplementation, most recently updated with contributions from Kreider and colleagues, states explicitly that creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes for increasing high-intensity exercise capacity and lean body mass during training. The position stand also notes that there is no scientific evidence that short- or long-term use of creatine monohydrate has any detrimental effects on otherwise healthy individuals when used at established guidelines.

What "Safe" Means in Research Terms

When researchers evaluate supplement safety, they look at specific biomarkers. For creatine, the key indicators include renal function markers (blood urea nitrogen, serum creatinine, glomerular filtration rate), hepatic enzymes (ALT, AST), lipid profiles, blood glucose, electrolyte balance, and hematological parameters. Studies measuring these markers before and after creatine supplementation periods ranging from weeks to years have consistently shown values remaining within normal clinical ranges.

Poortmans and Francaux (1999), in a study published in Medicine & Science in Sports & Exercise, specifically examined renal function in creatine users. They found no evidence of impaired renal function as measured by glomerular filtration rate, albumin excretion rate, or serum creatinine (when properly interpreted). This study became foundational in addressing the persistent myth that creatine damages kidneys.

A critical distinction researchers make is between an elevated serum creatinine reading and actual kidney dysfunction. Creatine is naturally converted to creatinine as a metabolic byproduct. Supplementation increases this conversion, which can elevate serum creatinine without any corresponding decline in kidney function. Clinicians unfamiliar with this mechanism sometimes misinterpret routine blood work in creatine users, a problem explored in detail in the article on creatine and creatinine levels.

Populations Studied

The breadth of populations studied strengthens the safety case considerably. Research has examined creatine supplementation in:

Trained athletes. Hundreds of studies have used competitive and recreational athletes as subjects. These individuals often take creatine for months or years. No pattern of adverse effects has emerged in any sport or training modality studied.

Older adults. With growing interest in creatine's potential to combat sarcopenia (age-related muscle loss) and cognitive decline, multiple studies have supplemented adults aged 55-80+ with creatine. These populations are particularly sensitive to kidney and cardiovascular stressors, yet no adverse effects have been reported.

Children and adolescents. While research in younger populations is more limited, existing studies in pediatric clinical settings (particularly for traumatic brain injury and muscular dystrophies) have not identified safety concerns. The ISSN notes that creatine may be a safer alternative to potentially dangerous anabolic substances that adolescents might otherwise seek.

Clinical populations. Creatine has been studied in patients with Parkinson's disease, Huntington's disease, ALS, muscular dystrophies, type 2 diabetes, traumatic brain injury, and depression. Even in these medically complex populations, the safety profile has remained favorable.

Common Concerns Addressed

Several safety concerns about creatine have achieved widespread cultural traction despite lacking clinical support. Each is addressed briefly here and in dedicated articles throughout this section.

Kidney damage. The most persistent concern. As detailed in the creatine and kidney health article, no controlled study has demonstrated kidney damage in healthy individuals taking creatine at recommended doses. The concern appears to originate from a single case report and confusion between creatinine levels and kidney function.

Dehydration and cramping. Early speculation suggested that creatine's intracellular water retention might cause dehydration or muscle cramps during exercise. Controlled studies, including the work of Lopez et al. (2009) and Greenwood et al. (2003), found the opposite: creatine users experienced equal or fewer instances of cramping and dehydration compared to non-users.

Hair loss. A single study by van der Merwe et al. (2009) in South African rugby players found elevated DHT levels after a creatine loading protocol. No actual hair loss was measured or reported. No subsequent study has replicated this finding. The details are covered in the creatine and hair loss article.

Liver damage. Hepatic function markers have been measured in numerous creatine trials. No evidence of liver damage or dysfunction has been found. See the creatine and liver function article for the clinical data.

Long-Term Data

Short-term safety is well-established, but long-term data strengthens the case further. Schilling et al. (2001) examined athletes who had used creatine for up to four years. Comprehensive metabolic panels showed no differences between long-term creatine users and non-users. Kreider et al. (2003) published similar findings from multi-year follow-ups.

The fact that creatine has been commercially available since the mid-1990s provides an additional layer of pharmacovigilance data. Millions of people have used creatine over three decades. If significant health risks existed at recommended doses, they would have generated signal in adverse event reporting systems and epidemiological data by now. No such signal has appeared.

Dose Matters

Safety data applies to established dosing protocols. The standard maintenance dose is 3-5 grams per day. Loading protocols use 20 grams per day (divided into 4 doses of 5 grams) for 5-7 days before dropping to maintenance. These protocols are the ones validated for both efficacy and safety.

Extremely high doses (beyond what studies have tested) fall outside the evidence base. This is true of any substance, including water. The safety literature does not support doses substantially above those used in controlled research, and there is no ergogenic reason to exceed them since muscle creatine stores have a saturation point.

Who Should Exercise Caution

While creatine is safe for the general healthy population, certain groups warrant additional consideration:

Pre-existing kidney disease. Individuals with compromised renal function should consult a nephrologist before supplementing. The safety data applies to healthy kidneys. While no study has shown creatine worsens existing kidney disease, insufficient research exists in this population to make definitive claims.

Pregnancy and breastfeeding. Research on creatine during pregnancy is emerging and shows theoretical promise (particularly for fetal neuroprotection), but the evidence is not yet sufficient to recommend supplementation during pregnancy without medical guidance. See the creatine during pregnancy article.

Medication interactions. Individuals taking nephrotoxic drugs or medications metabolized through the kidneys should discuss creatine use with their physician. Theoretical interactions exist, though clinically significant interactions have not been documented. The drug interactions article covers this in detail.

The Bottom Line

Creatine monohydrate has been studied more extensively than any other sports supplement. Across 500+ peer-reviewed papers, in populations ranging from children to the elderly, from healthy athletes to clinical patients, the safety data is remarkably consistent. At recommended doses of 3-5 g/day, creatine monohydrate does not damage the kidneys, liver, or heart. It does not cause dehydration, cramping, or hair loss. It is not a steroid and does not function as one.

The position statements from the ISSN, the accumulated clinical trial data, and three decades of widespread commercial use all point to the same conclusion: creatine monohydrate is safe for healthy individuals. The appropriate caveats involve pre-existing medical conditions and unstudied populations, which is standard for any supplement or dietary intervention.