Examining the Evidence
Q Do androgen levels help diagnose low libido?
<huc>A</huc> No. Clinical measures of circulating androgens are not useful in the diagnosis of low libido and other forms of female sexual dysfunction.
In women, androgen insufficiency is generally defined as a cluster of symptoms and signs—diminished well-being, unexplained fatigue, decreased sexual desire, and thinning pubic hair—in the presence of decreased bioavailable testosterone and normal estrogen. However, we lack evidence that this syndrome can be diagnosed by measuring circulating androgens.
Davis and colleagues explored the question by randomly recruiting 1,423 women aged 18 to 75 from the electoral rolls of Victoria, Australia. Voting is mandatory in Australia, where every adult is on the rolls; thus, the study population represented a cross-section of the general female adult population in that country.
After exclusions, Davis et al measured circulating androgens and sexual function (by a self-reported scale) in 1,021 women. The objective: to determine whether women who reported “low sexual well-being” were more likely to have low serum androgen levels than women who did not.
No correlation between testosterone and libido
Davis and colleagues found no evidence that total or free testosterone levels help determine which women have low sexual function. Although significant associations were noted between low levels of dehydroepiandrosterone sulfate (DHEAS) and sexual dysfunction, Davis et al found no diagnostically useful reason to measure DHEAS. Most women with low DHEAS reported no sexual dysfunction, and most women with sexual dysfunction lacked low DHEAS.
The likelihood of a clinically useful association between women with low sexual function and a low androgen level was greatest when the proportion of women with low sexual function was small (less than the fifth percentile) and the normal range for the serum androgen level was relatively large, such as the DHEAS level among young women.1
Still no correlation in women at midlife
In the second study, Dennerstein et al used data collected over 8 years from the Melbourne Women’s Midlife Health Project, a prospective, longitudinal, population-based study of Australian women aged 45 to 55. They chose this age group because hormonal changes during the menopausal transition “do not occur in a vacuum.” Rather, the midlife years coincide with other transitions as children leave home and parents age. In addition, some women may lose or change sexual partners, some of whom have their own problems with sexual function. The authors wanted to determine whether women’s sexual function is more dependent on psychosocial and relationship factors than on actual hormone levels.
The study involved annual measurements of both sexual function (by questionnaire) and hormone levels. Data were available from 336 women.
The findings: Only estradiol levels had a direct effect on sexual function, and then only on sexual response and dyspareunia. However, estradiol levels were less important than prior levels of sexual function, a change in partners, or feelings for the partner. Testosterone and DHEAS levels did not correlate with sexual function.
So how do we diagnose low libido?
Although a correlation may exist between low levels of circulating androgens and sexual dysfunction,2 there is no consensus on the clinical utility of measuring androgens to diagnose it. These studies are consistent with others that have failed to find serum testosterone levels useful in diagnosing androgen insufficiency. 3
One possibility may be that commercial assays for testosterone lack sufficient sensitivity and reliability to accurately measure the low levels of testosterone found in women, although the authors of both studies used reliable and reproducible methods.
Thus, for the time being, at least, androgen insufficiency syndrome remains a clinical diagnosis.
The commentators report no financial relationships relevant to this article.
1. Davison S, Bell R, Donath S, Montalto J, Davis S. Androgen levels in adult females: changes with age, menopause and oophorectomy. J Clin Endocrinol Metab. In press.
2. Turna B, Apaydin E, Semerci B, Altay B, Cikili N, Nazli O. Women with low libido: correlation of decreased androgen levels with female sexual function index. Int J Impot Res. 2005;17:148-153.
3. Bachmann G, Bancroft J, Braunstein G, et al. Female androgen insufficiency: the Princeton consensus statement on definition, classification, and assessment. Fertil Steril. 2002;77:660-665.