Creatine Safety: The Complete Evidence-Based Guide

This is the most comprehensive safety resource on this site. It synthesizes the evidence reviewed across all dedicated safety articles into a single reference, covering every major concern, every population studied, and every organ system examined. If you read one article about creatine safety, make it this one.

Creatine monohydrate has been commercially available since the early 1990s and has been the subject of over 500 peer-reviewed studies. It is the most researched sports supplement in history. The International Society of Sports Nutrition (ISSN), the American College of Sports Medicine, and the European Food Safety Authority have all evaluated its safety. Their conclusion is consistent: creatine monohydrate at recommended doses is safe for healthy individuals.

What Creatine Is and How It Works

Creatine is a naturally occurring amino acid derivative synthesized in the human body from arginine, glycine, and methionine. The liver, kidneys, and pancreas produce approximately 1-2 grams per day. An additional 1-2 grams per day comes from dietary sources, primarily meat and fish. The body stores approximately 120-140 grams of creatine, with 95% residing in skeletal muscle as free creatine and phosphocreatine.

Phosphocreatine serves as a rapid energy buffer. When ATP (the cell's energy currency) is depleted during high-intensity activity, the enzyme creatine kinase transfers a phosphate group from phosphocreatine to ADP, regenerating ATP within seconds. Supplementation increases intramuscular creatine and phosphocreatine stores to their saturation point (approximately 160 mmol/kg dry muscle), enhancing this energy buffering capacity.

This mechanism is entirely distinct from how anabolic steroids, stimulants, or other performance-enhancing substances work. Creatine does not bind hormone receptors, does not stimulate the nervous system, and does not alter endocrine function.

Kidney Safety

The most widespread safety concern is kidney damage. The evidence conclusively refutes this claim in healthy individuals.

Poortmans and Francaux (1999) measured glomerular filtration rate (GFR) directly in creatine users and found no impairment. Lugaresi et al. (2013) used cystatin C, a kidney marker unaffected by creatine intake, and confirmed normal renal function after 12 weeks at 10 g/day. Gualano et al. (2008) even studied creatine supplementation in a person with a single kidney and found no adverse effects. Kreider et al. (2003) tracked kidney markers across 21 months of continuous supplementation with no abnormalities.

The confusion arises because creatine is metabolized to creatinine, a standard marker used to estimate kidney function. Supplementation increases creatinine production, which elevates serum creatinine on blood tests. This creates the appearance of reduced kidney function when the kidneys are actually working normally. Cystatin C testing resolves this artifact.

Caveat: Individuals with pre-existing kidney disease should consult a nephrologist before supplementing. The safety data applies to healthy kidneys.

Detailed article: Creatine and Kidney Health

Liver Safety

Liver function markers (ALT, AST, GGT, ALP, bilirubin) have been measured in numerous creatine trials spanning weeks to years. No study has found evidence of hepatotoxicity. Kreider et al. (2003) tracked liver enzymes across 21 months without detecting abnormalities. Schilling et al. (2001) found no differences between long-term creatine users and non-users.

Interestingly, exogenous creatine supplementation may reduce the liver's biosynthetic workload. The liver normally synthesizes creatine via the GAMT enzyme. When dietary creatine is adequate, endogenous synthesis downregulates, potentially reducing hepatic metabolic demand.

Detailed article: Creatine and Liver Function

Cardiovascular Safety

Blood pressure, lipid profiles, and cardiac function markers are either unaffected or mildly improved by creatine supplementation. Earnest et al. (1996) found reductions in total cholesterol and triglycerides. Steenge et al. (2001) demonstrated that creatine supplementation reduced plasma homocysteine, an independent cardiovascular risk factor. No study has found elevated blood pressure, arrhythmias, or other cardiovascular adverse effects.

The heart itself relies heavily on the phosphocreatine energy shuttle. Cardiac creatine depletion is a hallmark of heart failure (Neubauer et al., 1997). Gordon et al. (1995) found that creatine supplementation improved ejection fraction in heart failure patients, positioning creatine as a potential therapeutic agent rather than a cardiovascular risk.

Detailed article: Creatine and Heart Health

Hair Loss

The hair loss myth originates from a single study. Van der Merwe et al. (2009) found elevated DHT (within normal physiological ranges) in 20 rugby players during creatine loading. No hair loss was measured, observed, or reported. No subsequent study has replicated the DHT finding. A 2021 meta-analysis by Antonio et al. of 22 studies found no effect of creatine on testosterone, free testosterone, or DHT.

The logical chain (creatine raises DHT, DHT causes hair loss, therefore creatine causes hair loss) fails at every link: the DHT elevation has not been replicated, circulating DHT is a poor predictor of individual hair loss, and no hair loss has ever been documented from creatine use.

Detailed article: Creatine and Hair Loss

Dehydration and Cramping

Creatine does not cause dehydration. Lopez et al. (2009) conducted a systematic review confirming no adverse effects on hydration status or exercise heat tolerance. Powers et al. (2003) demonstrated that creatine increases total body water without depleting extracellular fluid. The body has more water available during creatine supplementation, not less.

Creatine does not cause muscle cramps. Greenwood et al. (2003) found that creatine-supplementing football players experienced fewer cramps, heat illnesses, and injuries than non-supplementing players. The ISSN position stand notes that the preponderance of evidence suggests creatine may reduce rather than increase cramping incidence.

Detailed articles: Creatine and Dehydration | Creatine and Muscle Cramps

Bloating and Gastrointestinal Issues

Creatine-related "bloating" encompasses two distinct phenomena. Intracellular water retention (1-3 kg during loading) is normal, expected, and potentially anabolic. It occurs inside muscle cells, not subcutaneously. Gastrointestinal discomfort (stomach cramping, nausea, diarrhea) is dose-dependent and occurs primarily with large single doses on an empty stomach. It is resolved by dividing doses, taking creatine with food, and ensuring adequate fluid intake.

Detailed article: Creatine and Bloating

Blood Sugar and Diabetes

Creatine does not worsen blood sugar control. Research in type 2 diabetic patients suggests it may improve glycemic management. Gualano et al. (2011) found that creatine combined with exercise training improved HbA1c and glucose tolerance more than exercise alone. The mechanism involves enhanced GLUT-4 glucose transporter expression in skeletal muscle (Op 't Eijnde et al., 2001). Kidney function was preserved in diabetic populations studied.

Detailed article: Creatine and Blood Sugar

Long-Term Safety

Multi-year controlled studies provide the strongest safety evidence. Schilling et al. (2001) found no health marker abnormalities in athletes supplementing for up to four years. Kreider et al. (2003) tracked 69 health markers across 21 months without detecting adverse trends. Three decades of commercial availability involving millions of users have not generated pharmacovigilance signals suggesting long-term harm.

Detailed article: Creatine Long-Term Safety

Drug Interactions

No clinically significant pharmacological interaction between creatine and any common medication has been documented. The primary interaction is diagnostic: elevated serum creatinine can confound kidney function estimates used for dosing renally-cleared medications. Theoretical caution applies when combining creatine with nephrotoxic drugs, diuretics, or hypoglycemic agents, based on the precautionary principle rather than documented adverse events. Disclosure of creatine use to healthcare providers is essential.

Detailed article: Creatine and Medication Interactions

Creatinine and Lab Work

Creatine supplementation raises serum creatinine because creatinine is a direct metabolic byproduct of creatine. Standard eGFR equations interpret this elevation as reduced kidney function, creating a false-positive result. Cystatin C-based eGFR provides accurate kidney function assessment unaffected by creatine intake. Creatine users should disclose supplementation before blood work and request cystatin C testing if kidney function flags are raised.

Detailed article: Creatine and Creatinine Levels

Pregnancy and Breastfeeding

This is the one area of genuine uncertainty. Animal studies suggest maternal creatine supplementation may protect the fetal brain during birth-related oxygen deprivation (Dickinson et al., 2014; Ellery et al., 2016). Human clinical trial data is insufficient to recommend for or against supplementation during pregnancy. Creatine is naturally present in breast milk. Pregnant and breastfeeding women should consult their obstetrician before supplementing.

Detailed article: Creatine During Pregnancy

Populations Studied

The safety evidence encompasses a remarkably broad range of populations:

Athletes (hundreds of studies, multiple sports, both sexes, recreational through elite). Older adults (55-80+, including sarcopenia and cognitive decline research). Children and adolescents (primarily clinical contexts, muscular dystrophies, TBI). Clinical patients (Parkinson's disease, Huntington's disease, ALS, muscular dystrophies, type 2 diabetes, depression, traumatic brain injury). Special populations (single kidney, vegetarians, military personnel).

The breadth of populations studied without adverse findings strengthens the safety case considerably. If creatine produced organ damage, the signal would have appeared in at least one of these populations.

What the ISSN Position Stand Says

The International Society of Sports Nutrition position stand on creatine (Kreider et al., 2017) represents the most authoritative consensus statement on creatine safety. Key conclusions include:

Creatine monohydrate is the most effective ergogenic nutritional supplement currently available for increasing high-intensity exercise capacity and lean body mass. 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. The only consistently reported side effect is weight gain from water retention. Creatine monohydrate is the most extensively studied and clinically effective form of creatine. Claims that different forms of creatine are safer or more effective than monohydrate are not supported by peer-reviewed evidence.

Recommended Dosing for Safety and Efficacy

The doses validated for both safety and efficacy are as follows:

Loading (optional): 20 g/day divided into four 5 g doses for 5-7 days. Saturates muscle stores rapidly. Associated with more GI symptoms and greater initial water retention. Not required for achieving saturation.

Maintenance: 3-5 g/day continuously. Achieves full saturation within 3-4 weeks without loading. This is the dose used in the majority of long-term safety studies.

No cycling required. Continuous daily supplementation maintains muscle creatine stores at saturation. There is no tolerance effect and no safety-based reason to cycle.

Who Should Consult a Physician First

While creatine is safe for the general healthy population, the following groups should discuss supplementation with their healthcare provider: individuals with pre-existing kidney disease, individuals with pre-existing liver disease, pregnant or breastfeeding women, individuals taking nephrotoxic medications, individuals taking medications with narrow therapeutic windows that are renally dosed, and children under medical care for chronic conditions.

These recommendations reflect the standard of care for any dietary intervention in medically complex populations, not evidence of harm from creatine specifically.

Frequently Asked Questions

Is creatine safe to take every day?

Yes. Creatine monohydrate at 3-5 grams per day has been studied continuously for up to 5 years with no adverse effects on kidney function, liver function, lipid profiles, blood glucose, or any other measured health marker. The ISSN position stand confirms daily supplementation is safe for healthy individuals.

Does creatine damage your kidneys?

No. Multiple controlled studies measuring actual kidney function (GFR, cystatin C, albumin excretion) have found no impairment in creatine users. Elevated serum creatinine in creatine users reflects increased creatinine production, not decreased kidney function. The ISSN confirms no evidence of renal dysfunction in healthy individuals.

Does creatine cause hair loss?

No study has measured or reported hair loss from creatine supplementation. The myth originates from a single 2009 study that found elevated DHT levels (within normal ranges) in 20 rugby players. This finding has never been replicated. A 2021 meta-analysis of 22 studies found no effect of creatine on testosterone or DHT.

Does creatine cause dehydration?

No. A systematic review by Lopez et al. (2009) found no evidence that creatine impairs hydration status or exercise heat tolerance. Creatine increases total body water, meaning the body has more water available, not less. Multiple studies in hot environments confirm no dehydration risk.

Is creatine a steroid?

No. Creatine is a naturally occurring amino acid derivative made from arginine, glycine, and methionine. It is produced by the liver, kidneys, and pancreas and obtained from dietary sources like meat and fish. It does not bind to androgen receptors, does not alter testosterone, and is not banned by any sports organization including WADA.

Can women take creatine?

Yes. Creatine works through the same energy system in both sexes. Research in female populations shows benefits for exercise performance, body composition, and potentially bone health. The 1-2 kg of intracellular water retention does not produce a bulky appearance.

Should I cycle creatine?

No. Creatine does not produce tolerance, and the phosphocreatine system does not downregulate with continued use. Muscle stores reach a saturation point and are maintained with daily supplementation. Long-term studies show continued safety without cycling. The ISSN recommends continuous daily use.

Can creatine raise my blood pressure?

No consistent evidence supports this concern. Multiple studies measuring blood pressure before and after creatine supplementation, including during loading phases, have found no significant elevation in normotensive individuals. The ISSN position stand confirms no adverse cardiovascular effects.

Is creatine safe during pregnancy?

This is currently uncertain. Animal studies suggest maternal creatine may protect the fetal brain during birth complications, but human clinical trial data is insufficient to recommend supplementation during pregnancy. Pregnant women should consult their obstetrician before taking creatine.

Why does creatine raise my creatinine levels?

Creatine is naturally converted to creatinine at a rate of about 1.7% per day. Supplementation increases your creatine pool, which increases creatinine production. This raises serum creatinine on blood tests without any change in kidney function. Ask your doctor for a cystatin C test for an accurate kidney function assessment.