The effects of exogenous testosterone on sexuality and mood of normal men

The effects of supraphysiological levels of testosterone, used for male contraception, on sexual behavior and mood were studied in a single-blind, placebo-controlled manner in a group of 31 normal men. After 4 weeks of baseline observations, the men were randomized into two groups: one group received 200 mg testosterone enanthate (TE) weekly by im injection for 8 weeks (Testosterone Only group), the other received placebo injections once weekly for the first 4 weeks followed by TE 200 mg weekly for the following 4 weeks (Placebo/Testosterone group). The testosterone administration increased trough plasma testosterone levels by 80%, compatible with peak testosterone levels 400-500% above baseline. Various aspects of sexuality were assessed using sexuality experience scales (SES) questionnaires at the end of each 4-week period while sexual activity and mood states were recorded by daily dairies and self-rating scales. In both groups there was a significant increase in scores in the Psychosexual Stimulation Scale of the SES (i.e. SES 2) following testosterone administration, but not with placebo. There were no changes in SES 3, which measures aspects of sexual interaction with the partner. In both groups there were no changes in frequency of sexual intercourse, masturbation, or penile erection on waking nor in any of the moods reported. The Placebo/Testosterone group showed an increase in self-reported interest in sex during testosterone treatment but not with placebo. The SES 2 results suggest that sexual awareness and arousability can be increased by supraphysiological levels of testosterone. However, these changes are not reflected in modifications of overt sexual behavior, which in eugonadal men may be more determined by sexual relationship factors. This contrasts with hypogonadal men, in whom testosterone replacement clearly stimulates sexual behavior. There was no evidence to suggest an alteration in any of the mood states studied, in particular those associated with increased aggression. We conclude that supraphysiological levels of testosterone maintained for up to 2 months can promote some aspects of sexual arousability without stimulating sexual activity in eugonadal men within stable heterosexual relationships. Raising testosterone does not increase self-reported ratings of aggressive feelings.