Creatine, an over-the-counter nutritional supplement, does not slow Parkinson’s disease (PD) progression, according to the results of a clinical trial published in the February 10 issue of the Journal of the American Medical Association. In fact, the study — one of the largest clinical trials for PD to date — was cut short when researchers collected enough data to conclude that creatine had no benefit compared to placebo.
There are currently no therapies proven to slow or stop PD progression, so finding one is an urgent research priority. On several counts, creatine seemed to show potential. Scientists had hypothesized that it might be able to boost the activity of mitochondria – the cell’s power plant – within neurons, and prevent them from dying. Laboratory studies in mice also suggested that creatine could protect neurons. Then, the results of a preliminary clinical trial provided grounds for studying creatine further. Plus, it seemed reasonably safe.
The large clinical trial was sponsored by the National Institute of Neurological Disorders and Stroke (NINDS), and involved more than three dozen researchers led by Karl Kieburtz, M.D., at the University of Rochester in Rochester, NY. From 2007 to 2010, the researchers recruited 1,741 study participants. All had been diagnosed with PD within five years of enrollment and were taking levodopa (Sinemet®). For five years or more, half of the participants took 10 grams of creatine monohydrate powder daily, mixed with their food; the rest took a placebo powder the same way. Neither medical personnel nor participants knew which powder was given to which person.
- By July 2013, 955 study participants — more than half — had been followed for five years. At this point, the researchers had collected enough data on PD progression among these participants to reach a statistically significant conclusion comparing creatine and placebo.
- As measured by PD symptoms, activities of daily living, walking, cognition, and quality of life, there was no difference in PD progression between participants who took creatine and those who took placebo.
- The researchers also found no difference in adverse events between the two groups.
What Does It Mean?
This study definitively shows that creatine supplements do not slow PD progression, but also do not cause any harm. These disappointing results, coming after early promise, serve as a reminder that clinical trials are experiments with unknown outcomes. The results also underscore the importance of this rigorous approach to evaluating potential treatments: double-blinded and placebo-controlled. Although this trial failed to reach its hoped for conclusion, continued analysis of the data collected in this trial will further enhance our understanding of PD. The search for therapies that can stop or slow PD continues in other clinical trials under way, as well as with basic research into the causes and potential cures for PD.
Writing Group for the NINDS Exploratory Trials in Parkinson Disease (NET-PD) Investigators (2015) Effect of Creatine Monohydrate on Clinical Progression in Patients With Parkinson Disease: A Randomized Clinical Trial.JAMA. February 10 DOI:10.1001/jama.2015.120