The effects of mesterolone on sperm count in idiopathic oligospermia.

Forty subfertile men with idiopathic oligospermia were randomly treated with mesterolone or with placebo for more than 4 months. Seminal analysis was performed thrice before treatment, and twice after 16 weeks of treatment. There was a significant increase of semen volume (P less than .05), mean sperm concentration (P less than .01), and mean total sperm count per ejaculate (P less than .01) with mesterolone therapy. Sperm motility and morphological characteristics were not modified by mesterolone therapy. Mesterolone was found to be effective in improving the sperm concentration in mild and moderate rather than in severe idiopathic oligospermia.