Research has shown that testosterone levels decline as men age, leading to increased body fat, muscle loss, decreased bone density, and changes in mobility and cognitive function. In theory, taking testosterone supplements should counter that natural process. But a Dutch study reported in January 2008 concluded that the supplements offer limited benefits.
Researchers randomly assigned 237 men between the ages of 60 and 80 with low testosterone levels to take either a placebo or a testosterone supplement twice a day for six months. They measured functional mobility by timing how long it took participants to stand up, walk a specified distance, and sit back down. They also measured leg and handgrip strength, assessed cognitive ability, and tested bone mineral density, body composition, and cholesterol.
Of the 207 men who completed the study, those who took testosterone supplements experienced a significant drop in body fat, but that didn’t improve mobility or muscle strength. There was no difference in cognitive function or bone mineral density between the two groups. Although those taking testosterone reduced their total cholesterol, their “good” HDL cholesterol dropped, too. Based on their findings, the researchers concluded that testosterone supplements don’t offer “a net benefit” after six months.
SOURCE: Emmelot-Vonk MH, Verhaar HJ, Nakhai Pour HR, et al. Effect of Testosterone Supplementation on Functional Mobility, Cognition, and Other Parameters in Older Men: A Randomized Controlled Trial. Journal of the American Medical Association 2008;299:39–52. PMID: 18167405.
Originally published April 23, 2008; Last reviewed April 11, 2011