• Bone. Several small studies showed increased bone density in some locations after testosterone therapy. However, many women received concomitant estrogens, so the studies were confounded, the team noted.
• Cognition. Several studies have hinted that testosterone may be protective against Alzheimer’s and other dementias in women, possibly by mediating the accumulation of neurotoxic amyloid beta brain plaques. Women taking the hormone scored better on cognitive tests, including verbal memory, as well as spatial and mathematical reasoning. “In addition to having neuroprotective effects, testosterone has positive effects on endothelial function and acts as a vasodilator, providing another potential pathway through which testosterone may confer neuroprotection,” the investigators said. Again, however, they felt that the body and quality of evidence were not enough to justify a recommendation.
• Cardiovascular. Higher endogenous testosterone in women has been associated with better endothelial function and lower carotid intima-medial thickness; exogenous testosterone has not been adequately studied. However, testosterone supplementation does not seem to negatively affect lipids or increase other cardiovascular risk markers.
• Body composition. Several large studies of women with testosterone-alone and testosterone-estradiol therapy found increased lean muscle mass and lower body fat mass. These results were seen in healthy women as well as those with Turner syndrome, anorexia nervosa, and HIV infections. “Thus,” the investigators concluded, “testosterone increases lean body mass and may decrease fat mass in women, but effects are less dramatic than in men.”
• Mood. Testosterone therapy resulted in improved mood and lower depression scores in several studies, but subjects in some were not screened for comorbidities, including sexual dysfunction.
• Side effects. The potential for masculinizing effects – acne, hirsutism, deepening of the voice, and androgenic alopecia – exists. They are dose dependent, uncommon, and short-lived once supraphysiologic levels are decreased. Findings on breast cancer risk are contradictory; the team said more study is necessary.
The task force commissioned a testosterone therapy meta-analysis of published randomized trials of testosterone-alone or in addition to hormone replacement therapy. “Across all trials, testosterone use was associated with a statistically significant improvement in satisfaction, pleasure, orgasm, and libido. The quality of evidence was moderate to high for pleasure and orgasm outcomes, and moderate for satisfaction and libido outcomes,” with minimal effect on lipids and none on hair growth or loss.
“However,” the task force wrote, “data on adverse effects were not extensive, particularly for long-term use,” with a follow-up of 6 weeks to 2 years.
Dr. Wierman had no financial disclosures. However, several coauthors had numerous disclosures, including financial ties with pharmaceutical companies.
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