It's too soon to recommend testosterone treatment for men with MS, but the findings deserve further study, note the researchers. They included Nancy Sicotte, MD, of the neurology department at the University of California, Los Angeles (UCLA).
MS is more common in women than men. Sex hormones, such as testosterone, may be partly responsible for the gender gap in MS prevalence, Sicotte's team notes.
Sicotte and colleagues tested testosterone on 10 men with relapsing-remitting multiple sclerosis, the most common form of MS.
The men were 29-61 years old (average age: 46) and had had MS for about 12 years, on average. They weren't using any disease-modifying drugs.
At the study's start, the men's average blood testosterone level was on the low side of normal.
Testosterone for MS
First, the men completed a series of mental skills tests and got their brains scanned using magnetic resonance imaging (MRI) technology.
The men repeated those tests over the next six months. During that time, they weren't taking testosterone.
After the six-month observation period, the men applied a testosterone gel to their upper arms once daily for a year. Lastly, they repeated the brain scans and mental skills test.
After a year of testosterone treatment, the men's average blood testosterone level was on the high end of the normal range, the study shows.
Testosterone treatment was associated with better scores on the mental skills test and a 67% slowdown in loss of brain volume. The men's lean muscle mass also rose with testosterone treatment.
Larger studies are needed to confirm the findings, note Sicotte and colleagues. Their study appears in the Archives of Neurology.