The nature of androgen action on male sexuality: a combined laboratory-self-report study on hypogonadal men.
Level 2 - randomized trial
Double-blind, placebo-controlled crossover trial.
PubMed 6874890 · doi:10.1210/jcem-57-3-557
What was done
Six hypogonadal men were evaluated to determine which components of male sexuality depend on androgen action. The study used a double-blind, placebo-controlled crossover design comparing placebo with 200 mg and 400 mg doses of testosterone enanthate. Outcomes included prospective daily self-report logs of sexual activity and feelings, all-night penile tumescence recordings, and laboratory psychophysiological measurements of erectile responses during exposure to erotic films and fantasy.
What was found
Erectile responses to erotic film and fantasy in hypogonadal men were not lower than in normal men, showing higher values on some parameters such as prolonged detumescence time. In three subjects who completed consistent daily logs, testosterone administration increased frequencies of sexual acts, sexual feelings, orgasms, and spontaneous erections. Nocturnal penile tumescence and spontaneous daytime erections were reduced at baseline in untreated hypogonadal men and significantly increased following testosterone treatment; however, laboratory erectile responses elicited by visual or fantasy stimuli were unaffected by testosterone.
Why it matters
This study provides evidence that androgens specifically regulate sexual interest, motivation, and spontaneous or nocturnal erections in men, whereas stimulus-evoked erectile capacity can occur independently of testosterone.
Limits
The sample size was extremely small (n = 6), and daily log data were available for only 3 participants. The abstract does not report specific numerical values, confidence intervals, exact p-values, or the duration of treatment phases.
Cited by
- supports Julian Davidson at Stanford conducted double-blind, placebo-controlled trials showing testosterone administration improves energy, mood, and libido in hypogonadal men.