Primary Research · 2017
International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine
Kreider RB, Kalman DS, Antonio J, et al. · Journal of the International Society of Sports Nutrition, 2017
Key finding
Reviews 500+ studies and concludes creatine monohydrate is the most effective ergogenic nutritional supplement for high-intensity exercise and lean body mass, with an excellent safety profile across populations.
Abstract
PubMed · PMID 28615996 →Creatine is one of the most popular nutritional ergogenic aids for athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations which may help explain the observed improvements in high intensity exercise performance leading to greater training adaptations. In addition to athletic and exercise improvement, research has shown that creatine supplementation may enhance post-exercise recovery, injury prevention, thermoregulation, rehabilitation, and concussion and/or spinal cord neuroprotection. Additionally, a number of clinical applications of creatine supplementation have been studied involving neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's, Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, brain and heart ischemia, adolescent depression, and pregnancy. These studies provide a large body of evidence that creatine can not only improve exercise performance, but can play a role in preventing and/or reducing the severity of injury, enhancing rehabilitation from injuries, and helping athletes tolerate heavy training loads. Additionally, researchers have identified a number of potentially beneficial clinical uses of creatine supplementation. These studies show that short and long-term supplementation (up to 30 g/day for 5 years) is safe and well-tolerated in healthy individuals and in a number of patient populations ranging from infants to the elderly. Moreover, significant health benefits may be provided by ensuring habitual low dietary creatine ingestion (e.g., 3 g/day) throughout the lifespan. The purpose of this review is to provide an update to the current literature regarding the role and safety of creatine supplementation in exercise, sport, and medicine and to update the position stand of International Society of Sports Nutrition (ISSN).
Abstract sourced from PubMed, a database of the U.S. National Library of Medicine. Displayed in the authors’ own words for context; our critique is in the sections below.
A
85/100
Strong evidence
Well-designed study that answers the question it set out to ask. Safe to treat the central finding as reliable, though edge cases may still vary.
Strengths
- ✓Replicated
- ✓Large sample size
Limitations
No major methodological limitations flagged.
Critique
As a position stand synthesizing over 500 primary studies, its grade reflects the aggregate evidence it summarizes — and the creatine literature is unusually deep. Creatine monohydrate has been replicated across decades, populations, and research groups. The main caveat is that ISSN member authors often have industry relationships with sports nutrition companies, and conclusions about safety in vulnerable populations (adolescents, renal disease, pregnancy) rely on extrapolation rather than direct trials.
What would be more convincing
A Cochrane systematic review conducted by independent methodologists would add a final confirmatory tier. For most purposes, though, the creatine evidence base is already among the most mature in any supplement category.
Reviewed 2026-04-21 · Opinion based on verifiable facts in the published paper.
What these flags mean for you
Each flag on this study comes with a plain-English breakdown of why it matters and how it should change the confidence you place in the result.
Replicated
What it means
Independent research groups have reproduced this finding in separate populations.
Why it matters
Replication is the strongest signal in science. A replicated finding is orders of magnitude more likely to be real than a novel one.
How to read around it
Treat the central claim as reliable. Edge cases (different populations, doses, formulations) may still vary.
Large sample size
What it means
The trial enrolled enough participants to detect realistic effect sizes with high statistical power.
Why it matters
Large samples shrink the role of chance. A positive finding in thousands is much less likely to be a fluke than the same finding in dozens.
How to read around it
Gives you more confidence the reported effect size is close to the true effect — but still doesn't prove the study is well-designed in other ways.
About the supplement
Creatine
Dose · mechanism · evidence grade · safety →
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How to read a study like this
The same questions worth asking about any research paper, not just this one. Worth a minute even if you trust the grade.
Who was studied, and do you resemble them?
Supplement effects often depend on baseline status. Vitamin D helps people who are deficient; iron helps people who are anemic. A result in people unlike you may not apply to you.
What was measured, and does it matter in daily life?
A study that shows a blood marker moved isn't the same as a study that shows people felt or functioned better. Ask what the outcome means in practice.
How large was the effect — not just whether it was significant.
'Statistically significant' only means the effect is unlikely to be zero. It doesn't tell you the effect is large enough to notice. Look for effect sizes, not just p-values.
Who paid for the trial, and what did they stand to gain?
Industry-funded trials are several times more likely to report positive results than independent ones. It's not usually fraud — it's subtle design and reporting choices. Weight accordingly.
Has anyone else replicated this?
Single positive trials are hypotheses. Replication by independent groups is what turns a hypothesis into reliable evidence. If the only positive trial is the one you're reading, wait.
Does the dose in the trial match what's being sold?
Supplement marketing routinely cites trials that used 5–10× the dose in the product. If the effective dose was 2 g/day and the capsule has 200 mg, expect roughly no effect.
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