Effects of androgen on sexual behavior in hypogonadal men.
Level 2 - randomized trial
Individual randomized, double-blind crossover trial
PubMed 447801 · doi:10.1210/jcem-48-6-955
What was done
Six adult hypogonadal men (aged 32–65 years; two with primary gonadal failure, four with secondary hypogonadism) participated in a double-blind randomized crossover study lasting approximately 5 months. Subjects received intramuscular injections once every 4 weeks of either vehicle control or testosterone enanthate at two dose levels (100 mg and 400 mg), with treatment order randomized within and among subjects. Outcomes included daily log records of sexual activity and erection frequency (including nocturnal erections and coitus) and mood assessment via the Profile of Mood States test.
What was found
The abstract does not report numerical values, standard deviations, or exact p-values. It reports significant dose-related increases in the frequency of erections, nocturnal erections, and coitus in response to testosterone, which closely tracked fluctuations in circulating testosterone levels. Behavioral responses were not mediated by changes in mood scores.
Why it matters
This study provided early experimental, double-blind evidence that testosterone directly and reliably stimulates male sexual behavior and erectile function in a dose-dependent manner rather than through a placebo effect or non-specific mood enhancement.
Limits
The sample size was extremely small (n = 6) with mixed etiologies of hypogonadism. The abstract omits all numerical data, effect sizes, and statistical values. The 4-week dosing interval was noted to allow subtherapeutic testosterone troughs between injections.
Cited by
- supports Julian Davidson at Stanford conducted double-blind, placebo-controlled trials showing testosterone administration improves energy, mood, and libido in hypogonadal men.