A healthy dose of testosterone may help some men when it comes to at least two medical conditions. New research suggests the male hormone may help men reduce their risk of stroke as well as improve symptoms of Parkinson's disease.

Two studies on the effects of testosterone were presented at the annual meeting of the American Academy of Neurology.

Study author Monika Hollander, MD, of the Erasmus Medical Center in the Netherlands, and colleagues found men who had low testosterone levels had a higher risk of suffering a stroke than those with normal or high testosterone levels. But testosterone only had a protective effect on nonsmokers. Smokers with higher testosterone levels did not have a lower risk or stroke.

More research is needed to understand how smoking and hormones interact to affect heart health and stroke risk.

A second, smaller study presented at the meeting suggests testosterone treatment can alleviate certain symptoms of Parkinson's disease in men who have low testosterone levels.

When the five patients studied received testosterone replacement therapy, researchers found symptoms such as fatigue, depression, anxiety, and sexual function improved greatly.

Testosterone deficiency affects about 20% to 25% of males over age 60 in the general population, and it turns out this deficiency may account for some of the symptoms seen in Parkinson's that aren't muscle related, says study author Mahlon DeLong, MD, of Emory University, in a news release.

Although more research in a larger number of patients is needed, researchers say testosterone treatment may be a valuable alternative to other medications, such as antidepressants, that don't tend to work well in some Parkinson's patients with low testosterone levels.