Is It Legit?
Insufficient Evidence
“Creatine helps muscle growth”
Educational, not medical advice. Always consult a qualified healthcare provider before changing your diet, supplements, or routine. Full disclaimer.
What the science says
Neither study behind this claim measured muscle growth in humans, so this page cannot show that creatine builds muscle. A 2009 review found creatine to be a safe, effective performance enhancer that may help preserve muscle mass in critically ill patients, and a separate study in broiler chickens found that a related compound supports muscle protein growth.
Creatine's reputation for safety and for boosting athletic performance is well established, and performance is closely linked to muscle growth, but the evidence collected here is indirect rather than a trial in healthy adults.
Full analysis
The evidence here comes from two indirect sources rather than a human trial on muscle growth. A 2009 review in the journal Critical Care Medicine lists creatine among the safest and most effective performance-enhancing supplements, and notes it may help preserve muscle mass in critically ill patients. A separate study in broiler chickens found that guanidinoacetic acid, the compound the body converts into creatine, supports muscle growth and energy use.
Neither paper is a controlled trial that measured muscle growth in healthy humans taking creatine. The review draws on the wider sports-nutrition literature on performance generally, and the animal study is about poultry farming, not human physiology.
This does not show how much muscle, if any, a healthy adult can expect to gain from creatine, and it says nothing about people outside athletic or critically ill populations.
The takeaway: creatine's reputation as a safe, effective supplement is well established, but the muscle-growth-specific evidence on this page is thin and indirect.
Key studies
The studies that carry the verdict.
[1]Performance-enhancing sports supplements: role in critical care.
Weitzel LR et al. · Critical care medicine · 2009
This review names creatine as one of the safest and most effective supplements for boosting athletic performance, with a possible role in preserving muscle function in critically ill patients.
View paper[2]The physiological role of guanidinoacetic acid and its relationship with arginine in broiler chickens.
Portocarero N et al. · Poultry science · 2021
In broiler chickens, guanidinoacetic acid (the compound the body turns into creatine) supported muscle growth by contributing to energy production and freeing up another amino acid, arginine, for other uses.
View paper