Is creatine harmful to the kidneys?

For people with healthy kidney function there is, according to the position statement of the International Society of Sports Nutrition, no convincing evidence of a harmful effect. A slightly raised creatinine lab value is usually a metabolic by-product and not harm, but it can distort blood values. In the case of an existing kidney disease, use should be clarified with a doctor beforehand.

Does creatine make you smarter or improve memory?

A meta-analysis found, overall, a small improvement in memory performance, especially in older adults. In younger people the effect was not significant. This is a signal to be taken seriously but limited, from few small studies - not evidence of a general increase in intelligence.

Is creatine a medicine?

No. In Germany and the EU creatine is classified as a dietary supplement or food ingredient, not as an authorized medicinal product and not subject to prescription. This also means that products are not tested for efficacy in the way medicines are and that quality can vary between providers.

Supplement6 min readLast reviewed: June 2026

Creatine: the most thoroughly researched supplement

Creatine is considered the most thoroughly studied dietary supplement in the field of sport - and rightly so: when it comes to its effect on strength and muscle mass, there are hundreds of controlled human trials spanning several decades. Unlike many hyped substances, creatine therefore rests on an unusually solid foundation of data. Even so, an honest assessment is worthwhile: some effects are very well documented, others - such as cognitive benefits - are promising but smaller and context-dependent. This article describes the mechanism of action, separates reliable evidence from claims and names the limits. It is no substitute for medical or nutritional advice and deliberately contains no dosage information.

Machine-assisted translation. The German original is the authoritative version.

Key points

Creatine monohydrate is one of the best-studied supplements of all; its effect on strength, muscle mass and high-intensity short-duration performance with training is well documented.
The mechanism rests on the rapid restoration of ATP via the phosphocreatine system during short, intense bouts of exertion.
A cognitive benefit is possible but smaller and visible mainly in older adults; the data rest on few, small studies.
In healthy people, creatine is regarded by professional societies as well tolerated; there is no convincing evidence of kidney damage with healthy kidney function.
Legally a dietary supplement, not a medicinal product - in the case of pre-existing conditions, pregnancy/breastfeeding or medication use, clarify with a doctor beforehand.

What creatine is and how it works

Creatine is a nitrogen-containing compound produced by the body itself. The body forms it on its own (primarily in the liver, kidneys and pancreas) and additionally takes it in through food - especially through meat and fish. The largest share is stored in the skeletal muscle, a considerable proportion of it in the form of phosphocreatine.

The central mechanism concerns the cell's rapid energy supply. During intense, short bouts of exertion, the muscle cell uses up its energy carrier ATP faster than it can be regenerated. Phosphocreatine serves here as a fast buffering system: via the enzyme creatine kinase, it releases its phosphate group and rapidly restores ATP. The ISSN position statement describes the creatine kinase/phosphocreatine system as a link between the sites of ATP formation and those of ATP consumption. Increased creatine storage in the muscle can improve this short-term energy provision - this is the plausible basis for the observed performance effects.

A substance produced by the body, additionally taken in through meat and fish
The main store is the skeletal muscle, partly as phosphocreatine
Works by rapidly restoring ATP during short, intense exertion
The most widely used and best-studied form is creatine monohydrate

What the research actually shows

Best documented is the effect on high-intensity, short bouts of exertion as well as on strength and muscle building in combination with training. The position statement of the International Society of Sports Nutrition (Kreider et al., 2017) describes creatine monohydrate as the most effective ergogenic dietary supplement currently available for increasing high-intensity performance capacity and fat-free body mass during training. This statement rests on a very broad body of human trials that has grown over decades - an unusually high degree of evidence for a supplement.

Less clear-cut, but increasingly studied, is a possible cognitive benefit. A systematic review with meta-analysis (Prokopidis et al., 2023, Nutrition Reviews) evaluated eight randomized controlled trials and found, overall, a small improvement in memory performance compared with placebo (SMD = 0.29). Notably: the effect was considerably more pronounced in older adults (66-76 years), while it was not significant in younger participants. This is a signal to be taken seriously but still limited - the studies are small, the heterogeneity is high, and cognitive effects should not be equated with the well-established muscle effects.

Very well documented: strength, muscle building and high-intensity short-duration performance with training
Indications of a memory benefit, especially in older adults - effect small
The cognitive data rest on few, small studies with high variability
Not everyone responds equally strongly (responders/non-responders)

Status, safety and limits

Legally, creatine is classified in Germany and the EU as a dietary supplement or food ingredient - it is not an authorized medicinal product and is not subject to prescription. This classification is important: dietary supplements are not tested for efficacy in the way medicines are, and product quality as well as purity can differ between providers.

Regarding safety, the data are comparatively reassuring for healthy individuals. The ISSN position statement concludes that short- and long-term use is well tolerated in healthy people, and finds no convincing evidence that creatine harms the kidneys in those with healthy kidney function. A later review article by the same professional society (Antonio et al., 2021) also classifies widespread concerns - such as kidney damage, hair loss or dehydration - as assumptions not supported by reliable evidence. What remains important: this reassurance applies to healthy individuals. In the case of an existing kidney or metabolic disorder, during pregnancy and breastfeeding, or when taking medication, use should be clarified with a doctor beforehand. A slight rise in the creatinine value, frequently observed in laboratory tests, is a metabolic by-product and not automatically a sign of kidney damage - but it can distort blood values and should be communicated to the doctor.

Legal status: dietary supplement/food, not a medicinal product
Good tolerability in healthy people according to the professional society
No convincing evidence of kidney damage with healthy kidney function
Pre-existing conditions, pregnancy/breastfeeding, medication: clarify with a doctor beforehand
A slightly raised creatinine lab value is explainable but should be communicated

Putting the hype in perspective

Creatine occupies a special position: whereas many supplements are above all marketing promises, creatine is in fact one of the few substances with a reproducible effect in well-controlled human trials. But this is precisely what also invites exaggeration. On social media, creatine is increasingly promoted as a universal remedy for brain performance, mood, sleep or anti-aging - these applications are to be understood as claims, not as established facts.

The realistic picture is as follows: for strength, muscle mass and short, intense exertion, the evidence is strong. For cognitive effects there is a plausible but small signal, most likely in older people or under stressful conditions such as sleep deprivation - reliable, large long-term studies are largely lacking here. Further-reaching promises should be viewed with skepticism. Creatine is well studied, but it is no panacea, and it replaces neither a balanced diet nor training nor medical treatment.

Strong evidence for muscle and strength, weaker for cognition
Applications such as mood, sleep or anti-aging are claims, not evidence
Large long-term studies on many non-sport effects are lacking
Well documented does not mean universally effective

Frequently asked questions

Is creatine harmful to the kidneys?: For people with healthy kidney function there is, according to the position statement of the International Society of Sports Nutrition, no convincing evidence of a harmful effect. A slightly raised creatinine lab value is usually a metabolic by-product and not harm, but it can distort blood values. In the case of an existing kidney disease, use should be clarified with a doctor beforehand.
Does creatine make you smarter or improve memory?: A meta-analysis found, overall, a small improvement in memory performance, especially in older adults. In younger people the effect was not significant. This is a signal to be taken seriously but limited, from few small studies - not evidence of a general increase in intelligence.
Is creatine a medicine?: No. In Germany and the EU creatine is classified as a dietary supplement or food ingredient, not as an authorized medicinal product and not subject to prescription. This also means that products are not tested for efficacy in the way medicines are and that quality can vary between providers.

Sources

This article is for information and education only. It does not replace medical advice and deliberately contains no dosing, usage or sourcing information.

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