Blood tests for testosterone cannot diagnose low sexual desire in midlife women

A recent study published in the journal Fertility and Sterility suggests that checking testosterone levels through a blood test is not an effective way to diagnose low sexual desire or other sexual difficulties in midlife women. Although the scientists found subtle links between certain hormones and physical experiences like arousal and orgasm, these hormones were not linked to sexual desire itself. The findings provide evidence that measuring testosterone and its chemical building blocks should not be a standard part of assessing women who seek medical help for sexual concerns.

Medical professionals have prescribed testosterone to help treat low sexual desire in postmenopausal women for over eighty years. Because of this established medical practice, there is a common belief that low blood testosterone levels might be the underlying physiological cause of sexual difficulties in women during their midlife years. Some medical providers have proposed that testing blood levels of this hormone could help identify exactly who might benefit most from testosterone therapy.

Susan R. Davis, Vice-Chancellor’s Distinguished Professor and director of the Women’s Health Research Program at Monash University, wanted to investigate these assumptions. “There are a lot of hypotheses and beliefs about hormones and sexual function, particularly testosterone and sexual function, and I wanted to establish the relationships between hormones and sexual function in women as a foundation for future research and clinical decision making,” Davis said. Davis also serves as the head of the Women’s Endocrine Clinic at Alfred Hospital in Melbourne.

Past research on how sex hormones relate to female sexual function has faced several technical and methodological limitations. Earlier studies often used traditional testing methods that struggle to accurately measure the naturally low levels of testosterone found in women. These older tests, known as immunoassays, tend to lack the precision needed to capture slight variations in female hormone levels.

Previous research has also sometimes failed to account for a woman’s specific stage of menopause, which is a biological detail that greatly affects sexual health. The transition into menopause involves significant shifts in ovarian function and hormone production. Failing to separate women into premenopausal and postmenopausal groups can obscure how different hormones affect the body at different stages of life.

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To address these gaps, the authors of the new study utilized a highly precise testing method called liquid chromatography with tandem mass spectrometry. This advanced technique separates and identifies molecules based on their weight and chemical properties, allowing for exact measurements of testosterone even at very low concentrations. It also allows scientists to measure testosterone alongside its chemical precursors from a single blood sample.

By combining this advanced testing technology with comprehensive behavioral surveys, the research team aimed to determine if blood concentrations of these hormones actually correspond to a woman’s sexual experiences. Specifically, they wanted to see if testosterone relates to desire, arousal, orgasm, or overall sexual responsiveness. They also wanted to know if women reporting severe sexual difficulties have noticeably lower hormone levels than women without such difficulties.

The researchers analyzed data from a broader project known as the Australian Women’s Midlife Years Study. This cross-sectional project recruited participants whose ages and geographic locations matched the general Australian population. For this specific analysis, the team included 731 participants between the ages of 40 and 69.

The sample was precisely divided based on reproductive stages, consisting of 136 premenopausal women with a median age of 45, and 595 women who were perimenopausal or postmenopausal with a median age of 61. Premenopausal women were defined as those with regular menstrual cycles. The perimenopausal and postmenopausal group included those experiencing irregular cycles or who had stopped menstruating entirely.

To measure sexual function, participants completed a detailed 37-item questionnaire designed to be inclusive of any sexual orientation or partner status. This survey asked women to recall their sexual experiences over the past thirty days. The answers generated specific numerical scores for desire, arousal, orgasm, and sexual responsiveness, with higher scores indicating better overall sexual function.

The team took extensive steps to ensure other medical and lifestyle factors did not skew the results. They excluded individuals who were pregnant, breastfeeding, using hormone therapies, or taking medications that alter hormone levels. They also removed participants with thyroid dysfunction or abnormal prolactin levels, as these conditions can independently cause hormonal and sexual disruptions.

Additionally, the researchers excluded women experiencing moderate to severe depression, or those taking psychiatric medications. Depression is strongly linked to sexual difficulties independent of natural hormone levels. By removing these participants, the scientists aimed to isolate the direct relationship between naturally occurring sex hormones and sexual function.

Eligible participants visited local clinics to provide blood samples for the laboratory analysis. Using the advanced mass spectrometry technique, the laboratory measured serum levels of testosterone alongside two precursor hormones, known as dehydroepiandrosterone and androstenedione. Precursor hormones are raw materials that the adrenal glands and ovaries produce, which the body then uses to manufacture other active hormones like testosterone and estrogen.

The data revealed that many women in the study experienced sexual difficulties. The overall prevalence of low sexual desire was about 24 percent, while 19 percent reported difficulties with arousal. About 10 percent of participants reported difficulties reaching orgasm, and nearly 8 percent struggled with overall sexual responsiveness.

When looking at the hormone levels, the researchers found no link between any of the measured hormones and sexual desire. After adjusting for variables like age, body mass index, relationship status, and past trauma, testosterone levels did not predict whether a woman experienced a lack of sexual interest. This lack of association was consistent across all menopausal stages.

“We found no relationship between any hormone measured and sexual desire/ libido,” Davis noted. “We did find a ‘signal’ that women reporting low orgasm tended as a group to have slightly lower testosterone blood levels than others, but there was huge overlap in testosterone levels between women with low and not low orgasm, so a blood level was not useful for distinguishing symptoms in an individual woman.”

The data did reveal complex, nonlinear associations between some hormones and other physical aspects of sexual function. In premenopausal women, testosterone levels showed a subtle, S-shaped association with the ability to orgasm. This means that orgasm scores did not simply go up as testosterone went up; instead, the relationship fluctuated at specific hormonal turning points.

For women in the perimenopausal and postmenopausal groups, androstenedione levels were linked to both arousal and orgasm scores. Similar to the premenopausal group, these relationships were nonlinear. While these statistical links were present, the researchers noted that the hormones only explained a very small percentage of the total variation in women’s sexual function scores.

When looking specifically at women who reported severe sexual difficulties, the researchers noted a few differences in hormone profiles. Perimenopausal and postmenopausal women who struggled specifically with reaching orgasm tended to have slightly lower median levels of testosterone, dehydroepiandrosterone, and androstenedione compared to women without this difficulty. A similar pattern emerged for women reporting persistent issues with sexual responsiveness.

Because medical providers sometimes use testosterone therapies to treat low sexual desire, people might misinterpret these findings to mean that testosterone plays absolutely no role in female sexual health. However, the authors point out that circulating blood levels only provide a proxy for the hormone concentrations actually present inside the body’s tissues. The body produces testosterone locally in tissues like the brain, vagina, and fat, where it exerts direct effects that may not be fully reflected in a standard blood draw.

Since a standard blood test only captures what is floating in the bloodstream, it misses the localized hormone activity that influences sexual responses. Looking at a lab result cannot tell a doctor if a woman is experiencing a functional hormone deficiency in her brain or pelvic tissues. This disconnect explains why doctors cannot rely on blood tests to guide their treatment plans, even if a patient might eventually respond well to hormone therapy.

“So, testing hormones is not useful in assessing low sexual function or how to treat low sexual function,” Davis explained. While prescribing extra testosterone might help boost desire for some women by increasing hormone levels in those specific tissues, a baseline blood test simply cannot predict who will benefit from that treatment.

The study has some limitations that provide context for the findings. The research was cross-sectional, meaning it only captured a single snapshot in time. This study design prevents scientists from determining cause and effect, as they cannot track whether a drop in hormones directly triggers a decline in sexual function over several years.

Additionally, the researchers relied on a single blood sample for each participant without standardizing the time of day the blood was drawn. In premenopausal women, blood collection was not timed to a specific phase of the menstrual cycle. While past data suggests median hormone levels only vary slightly across the menstrual cycle, this lack of precise timing could have introduced minor measurement errors.

The team also could not capture every possible psychosocial factor that might influence sexual health. “We took into account a lot of variables in the analysis but we did not take into account relationship duration or relationship discord,” Davis said.

Future research could involve collecting multiple blood samples over time to see if fluctuating hormone levels correspond to long-term changes in a woman’s sexual function. Scientists might also look closer at how precursor hormones convert into active hormones directly within specific body tissues, rather than just measuring what is circulating in the bloodstream.

The researchers also plan to investigate whether prescribing hormones provides therapeutic benefits, even if baseline blood tests are not useful for diagnosis. “We are recruiting premenopausal and perimenopausal women with low libido to a study to see if testosterone improves libido in these women,” Davis added.

The lack of an obvious link between blood testosterone and libido highlights that sexual desire relies heavily on a complex mix of psychosocial and biological factors that a simple blood test cannot capture. The current evidence suggests that measuring these hormones is not a reliable diagnostic tool for clinicians, and physicians should explore broader psychological and relational factors when treating midlife women. You can follow Davis and her ongoing work on Instagram at professorsusandavis.

The study, “Associations between testosterone and pre-androgens and sexual function; findings from the Australian Women’s Midlife Years Study,” was authored by Yuanyuan Wang, Rakibul M. Islam, Alice Hodge, David J. Handelsman, Md Nazmul Karim, Molly Bond, and Susan R. Davis.