Effect of creatine monohydrate on clinical progression in patients with Parkinson disease: a randomized clinical trial.

This was a multicenter randomized clinical trial at 45 investigative sites in the United States and Canada. Adults with early Parkinson disease who were receiving dopaminergic therapy were randomized 1:1; the creatine arm included 874 participants.

Creatine monohydrate was given orally as identical 7-g sachets containing 5 g creatine, mixed with food and taken twice daily for a total dose of 10 g/day. Treatment was continued for at least 5 years, with up to 8 years for the first enrollees, and was compared with placebo.

Creatine monohydrate did not slow clinical progression in Parkinson disease. The primary Global Statistical Test at year 5 was not significant (t = -0.75, 2-sided P = .45), and most secondary outcomes were also similar between groups, including total LEDD at year 5 (difference 45, 95% CI -14 to 103; P = .14) and UPDRS total change (-0.9, 95% CI -3.1 to 1.3). The trial authors concluded that creatine monohydrate for at least 5 years did not improve clinical outcomes compared with placebo and does not support use to slow progression in patients with Parkinson disease.

The intervention showed no efficacy despite a large, long-term trial, so any benefit is unlikely to be clinically meaningful in this population. Findings are specific to early, treated Parkinson disease at the tested dose and schedule, and the report does not provide completer counts or other attrition details in the extracted data.