Sexual dysfunction and low libido are among the most easily reversible symptoms of hypogonadism. Systematic reviews of randomized, placebo-controlled clinical trials of testosterone in men, including older men (aged 60 years and over) and middle-aged men, with sexual dysfunction and hypogonadism have shown large favourable effects on libido and moderate effects on satisfaction with erectile function.1-5 In men who do not respond sufficiently to testosterone therapy alone, the combination of phosphodiesterase 5-inhibitors and testosterone may be indicated, as there are suggestions that the combination may be synergistic.1

Testosterone is a sex hormone that plays important roles in the body. In men, it’s thought to regulate sex drive (libido), bone mass, fat distribution, muscle mass and strength, and the production of red blood cells and sperm. A small amount of circulating testosterone is converted to estradiol, a form of estrogen. As men age, they often make less testosterone, and so they produce less estradiol as well. Thus, changes often attributed to testosterone deficiency might be partly or entirely due to the accompanying decline in estradiol.


Ashwagandha is sometimes included in testosterone supplements because of the hypothesis that it improves fertility. However, we couldn’t find sufficient evidence to support this claim (at best, one study found that ashwagandha might improve cardiorespiratory endurance). WebMD advocates caution when taking this herb, as it may interact with immunosuppressants, sedative medications, and thyroid hormone medications.

Although some men believe that taking testosterone medications may help them feel younger and more vigorous as they age, few rigorous studies have examined testosterone therapy in men who have healthy testosterone levels. And some small studies have revealed mixed results. For example, in one study healthy men who took testosterone medications increased muscle mass but didn't gain strength.

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