December 5, 2013
Study Offers Hope For Middle-Aged Women’s Sex Drive
Middle age and beyond can take a toll on a woman's sex drive, but two new studies offer hope for women who want to get their sexual mojo back.
So far, no testosterone treatment has been approved for women by the FDA. After surgical or natural menopause, an important step to developing a successful and safe treatment is to find out exactly how much testosterone is really needed to bring back sexual desire. This was the focus of one of the studies published in the journal Menopause.The study also looked at how much of the hormone it took to produce other testosterone-related effects, such as increases in lean body mass, in women who had undergone a hysterectomy. The second study assessed a a nonhormonal therapy, flibanserin, which did not meet FDA approval before but has since been resubmitted to the agency.
In 2010, when the FDA first reviewed flibanserin, they did not believe it made a meaningful difference compared to a placebo. In the new study, women who had a very low sex drive and were distressed about it demonstrated statistically significant differences.
The participating women took 100mg/day at bedtime and showed increases in the number of satisfying sexual encounters (SSEs) and in a standard score of desire that were statistically better than with a placebo. Side effects, which included dizziness, sleepiness, nausea, and headache were experienced by 30 percent of the women in the study, but only 8 percent stopped taking the drug because of them.
Women, ages 21 to 60 who had undergone hysterectomy, participated in the testosterone study. All had testosterone levels below the average for healthy young women. After menopause, ovaries continue to secrete male hormones, meaning that there is usually little decrease in testosterone levels for women who go through menopause naturally.
For women who undergo any sort of hysterectomy, however, testosterone levels drop substantially. Removing one or both ovaries, even if the patient takes estrogen, worsens sexual function compared to women who retain one or both ovaries. All of the participants were given estrogen, along with injections of a placebo or different doses of testosterone enenthate for six months.
Women who received the highest dosage—25 mg weekly—were the only group to show significant improvements in their libido and other measurements of sexual function. They also showed significant improvements in lean body mass and muscle strength. At that dosage, testosterone levels were raised to approximately 210ng/dL, which is five to six times higher than a healthy, normal level. This suggests that simply raising low testosterone levels to what's normal won't improve sexual function and these other measures.
The research team observed no serious side effects. There were no significant changes in total or LDL cholesterol, triglycerides, or fasting glucose in the women who received testosterone. HDL, or "good cholesterol," did decrease, but not in a statistically significant way. The researchers caution that cardiovascular and metabolic risks need to be investigated in long-term trials.
"Keeping hormone levels within the normal range for your gender and age is the safest approach. Hormones affect many systems in the body, and it takes a large and long-term study to identify side effects. One recent well-designed study in men reported that mortality was greater among older men taking testosterone. More is not necessarily better when it comes to hormones," says The North American Menopause Society Executive Director Margery Gass, MD.