Without adequate levels of free testosterone, the quality of a man's sex life is impacted and the genitals atrophy. When free testosterone is restored, positive changes in structure and function of the sex organs can be expected. (It should be noted that sexual dysfunction can be caused by other factors unrelated to hormone balance such as arteriosclerotic blockage of the penile arteries.)
The genital/pelvic region is packed with testosterone receptors that are ultra-sensitive to free testosterone-induced sexual stimulation. Clinical studies using testosterone injections, creams, or patches have often failed to provide a long-lasting libido enhancing effect in aging men. (98) We now know why. The testosterone can be converted to estrogen. The estrogen is then taken up by testosterone receptor sites in cells throughout the body. When an estrogen molecule occupies a testosterone receptor site on a cell membrane, this blocks the ability of serum testosterone to induce a healthy hormonal signal. It does not matter how much serum free testosterone is available if excess estrogen is competing for the same cellular receptor sites.
Estrogen can also increase the production of sex hormone-binding globulin (SHBG), which binds the active free testosterone into a non-active "bound testosterone". Bound testosterone is not able to be picked up by testosterone receptors on cell membranes. For testosterone to produce long-lasting libido enhancing effects, it must be kept in the "free" form (not bound to SHBG) in the bloodstream. It is also necessary to suppress excess estrogen as this hormone can compete for testosterone receptor sites in the sex-centers of the brain and the genitals.
Restoring youthful hormone balance can have a significant impact on male sexuality.