Best known as a legal performance-enhancing supplement for athletes looking to build muscle mass, creatine appeared to help muscular dystrophy patients build muscle mass as well.
The supplement's effects were modest, say the researchers who conducted the review.
Twelve studies involving 266 people were included in the review. When the results were combined, taking creatine, either short-term or long-term, was found to improve muscle strength by an average of 8.5% among patients with various types of muscular dystrophy.
Creatine users also gained an average of 1.4 pounds of lean body mass compared with patients taking placebo treatments.
'A Useful Therapy'
The review was commissioned by the Cochrane Collaboration, an independent organization that produces systematic reviews of research into current medical practices. The findings are published in the latest issue of the organization's journal, The Cochrane Library.
"These studies show that creatine is a useful symptomatic therapy," researcher Matthias Vorgerd tells WebMD. "It is not a cure, and its effects were modest, but this is something that patients should consider."
Creatine is produced naturally in the body. For decades, bodybuilders and other athletes have taken creatine in supplement form in an effort to boost athletic performance. Its use is allowed by amateur and professional sporting organizations.
People with the group of disorders collectively known as muscular dystrophy often have low levels of natural creatine. The thinking has been that raising these levels with creatine supplements could help improve muscle function.
Though this seems to be true in patients with muscular dystrophy, creatine supplementation was not found to be useful in patients with a related group of disorders known as metabolic myopathies.
In muscular dystrophy patients, the proteins that make up the muscles are either damaged or missing, while in patients with metabolic myopathies, the defect lies in body chemicals that can affect the muscles.
Vorgerd says it is not clear why muscular dystrophy patients seemed to benefit from creatine supplementation while those with metabolic myopathies did not.
In their newly published report, the researchers called for new studies to address this and other unanswered questions.
Muscular Dystrophy Association Medical Director Valerie Cwik, MD, says the research suggests creatine may be more beneficial for some forms of muscular dystrophy than for others.
"Responses have been variable across the different dystrophies, and I don't think the review really makes that clear," she tells WebMD. "That is why it is so important that patients talk to their treating physicians about the pros and cons of creatine supplementation."
SOURCES: Kley, R.A. The Cochrane Library, 2007; online edition. Rudolf Kley, Ruhr University Bochum, Bochum, Germany. Matthias Vorgerd, Ruhr University Bochum, Bochum, Germany. Valerie Cwik, MD, medical director and vice president for research, Muscular Dystrophy Association.
By Salynn Boyles
Reviewed by Louise Chang