A team led by Dr. Joel Finkelstein at Massachusetts General Hospital investigated testosterone and estradiol levels in 400 healthy men, 20 to 50 years of age. To control hormone levels, the researchers first gave the participants injections of a drug that suppressed their normal testosterone and estradiol production. The men were randomly assigned to 5 groups that received different amounts (from 0 to 10 grams) of a topical 1% testosterone gel daily for 16 weeks. Half of the participants were also given a drug to block testosterone from being converted to estradiol.
• Evaluate formulation-specific adverse effects at each visit:
- Intramuscular injections of testosterone enanthate and cypionate: Ask about fluctuations in mood or libido.
- Testosterone patches: Look for skin reaction at the application site.
- Testosterone gels: Advise patients to cover the application sites with a shirt and to wash the skin with soap and water before having skin-to-skin contact because testosterone gel leaves a residue on the skin that can be transferred to a woman or child who comes in close contact. Serum testosterone levels are maintained when the site is washed 6 hours after applying the gel.
Although there is clear evidence that many women with low testosterone levels do not experience sexual dysfunction, there is also evidence that testosterone plays a role in regulating female sexual desire and response. For example, studies have correlated low testosterone levels in women with decreased orgasmic ability, sexual pleasure and reduced libido. There is also evidence that women’s response to sexual stimuli (. erotic videos, sexual contact) is increased and that women have sex more frequently, during the mid point of their menstrual cycle, at which time testosterone levels are highest and they are also most fertile. In addition, there is evidence that testosterone levels increase in response to sexual stimuli. For example, a study in which women masturbated to orgasm reported that the women’s testosterone levels increased after orgasm.