What role does testosterone play in the sexual function of middle aged to older men? We have long known the importance of testosterone, and its role in the sexual function of young men. This study set out to find the importance of: Testosterone, Free Testosterone, Estrogen and DHT in the sexual function of middle aged to elderly men. All of the research up to this point had been done in the United States and only took measure of international index of erectile dysfunction (IIED) or a single measure from the Massachusetts Male aging Study. Neither of which recorded the frequency of intercourse or the frequency of masturbation.

Although low total testosterone is common in men with ED it is usually not the primary reason for the failure. Researchers set out to find out what other hormones played a significant role in sexual function.


Results: Total and free T, but not E2 or DHT, was associated with overall sexual function in middle-aged and older men. E2 was the only hormone associated with sexual function-related distress such that higher levels were related to greater distress. Free T levels were associated with masturbation frequency and erectile dysfunction in the fully adjusted models, such that higher T was associated with less dysfunction and greater frequency. Moreover, there was a T threshold for the relationship between total T, sexual function, and erectile dysfunction. At T concentrations of 8 nmol/liter or less, T was associated with worse sexual functioning, whereas at T levels over 8 nmol/liter, the relationship came to a plateau.


Conclusions: These findings suggest that different hormonal mechanisms may regulate sexual functioning (T) vs. the psychological aspects (E2) of male sexual behavior. Moreover, there was a T threshold for overall sexual function such that at levels greater than 8 nmol/liter the relationship between T and sexual function did not become stronger.

jcem.endojournals.org/content/early/2011/08/11/jc.2010-2216.abstract