Testosterone plays a surprisingly central role in women’s bodies, influencing everything from sexual desire and mood to bone strength and how the body builds muscle. Women produce far less testosterone than men, with normal adult levels falling below 40 ng/dL compared to several hundred in men, but that smaller amount is essential. The ovaries and adrenal glands together produce about 40% to 50% of a woman’s testosterone, with the rest converted from other hormones in tissues like fat, bone, and skin.
How Testosterone Shapes Sexual Desire
The most well-studied role of testosterone in women is its effect on libido. Androgen receptors and estrogen receptors are both present in the female brain, and the hypothalamus, a brain region that regulates sexual behavior, contains testosterone concentrations roughly tenfold higher than estrogen concentrations. That high local concentration helps explain why testosterone has such a direct influence on sexual motivation.
When testosterone levels drop, some women experience a persistent loss of sexual desire that goes beyond normal fluctuations. If that loss lasts six months or more and causes significant personal distress, it may meet the criteria for hypoactive sexual desire disorder (HSDD). This isn’t about having a lower sex drive than a partner or compared to some external standard. The distress piece matters: the condition is defined by a woman’s own experience of frustration, sadness, or worry about her absent desire.
Clinical trials have shown that restoring testosterone through a skin patch can meaningfully improve desire. In one large study, women using a transdermal testosterone patch reported about 2.1 additional sexually satisfying events per month, compared to about 1 per month with placebo. The 52-week APHRODITE trial confirmed that improvements in desire and reductions in sex-related distress held up over a full year of treatment.
Its Role as an Estrogen Building Block
Testosterone isn’t just active on its own. It also serves as a raw material your body uses to make estrogen. Through a process called aromatization, an enzyme converts testosterone into estradiol, the most potent form of estrogen. This conversion happens in fat tissue, bone, the brain, and blood vessels, meaning testosterone quietly supports estrogen-dependent functions throughout the body even in tissues far from the ovaries. For women approaching or past menopause, this conversion pathway becomes one of the body’s remaining sources of estrogen after ovarian production declines.
Muscle, Strength, and Body Composition
The relationship between testosterone and muscle in women is more nuanced than many people assume. A 2024 study of premenopausal women found that total testosterone levels did not predict how much muscle mass or strength a woman had at baseline, or how much she gained from 12 weeks of resistance training. However, the free androgen index, which reflects the amount of testosterone actually available for use rather than bound to proteins in the blood, did correlate with strength gains from training.
This distinction matters. Most circulating testosterone in women is bound to a protein called SHBG, which essentially takes it out of play. The fraction that remains unbound, or “free,” is what interacts with tissues. So two women with the same total testosterone level could have very different amounts of active hormone depending on their SHBG levels, which shift with weight, insulin levels, and other factors.
Mood, Energy, and Well-Being
Beyond sexual function, testosterone contributes to a general sense of vitality. A 12-week randomized controlled trial found that women receiving testosterone cream reported significantly improved well-being and mood compared to those on placebo. This aligns with what many women describe anecdotally when their levels are low: fatigue, a flattened mood, and a harder-to-define feeling of something being “off.” These effects likely stem from testosterone acting directly on androgen receptors in the brain rather than only through its conversion to estrogen.
What Happens When Levels Are Too High
If testosterone is beneficial in normal amounts, too much creates real problems. Excess testosterone in women, called hyperandrogenism, causes a recognizable cluster of symptoms:
- Acne and oily skin
- Excess body hair growing in typically male patterns (face, chest, back)
- Thinning hair on the scalp in a male-pattern baldness distribution
- Irregular or absent periods
- Difficulty getting pregnant
Polycystic ovary syndrome (PCOS) is the most common cause. A key driver is insulin resistance: when insulin levels run high, the liver produces less SHBG, that binding protein that keeps testosterone in check. With less SHBG in circulation, more testosterone is free and active. Obesity compounds this by worsening insulin resistance, creating a cycle that pushes free testosterone even higher. This is why lifestyle changes targeting insulin sensitivity, like regular exercise and dietary adjustments, can meaningfully improve symptoms for many women with PCOS.
Testosterone Therapy for Women
A 2019 Global Consensus Position Statement, developed by an international panel of experts, concluded that the only evidence-based reason to prescribe testosterone to women is HSDD. The panel found a moderate therapeutic effect for that condition but insufficient data to recommend testosterone for anything else, whether that’s fatigue, bone loss, or general anti-aging purposes.
The recommended form is a transdermal product, meaning it absorbs through the skin. Oral testosterone is specifically not recommended because it raises LDL (“bad”) cholesterol and lowers HDL (“good”) cholesterol. Transdermal delivery avoids this effect by bypassing the liver on its first pass through the body. Meta-analyses of transdermal testosterone at physiological doses have not identified severe adverse events, though long-term safety data beyond a few years remains limited.
Compounded testosterone preparations, the custom-mixed formulations available through specialty pharmacies, are not endorsed by the consensus statement because they lack standardized efficacy and safety data. Dosing can vary significantly between batches, making it harder to keep levels in the intended range. While the global guidelines focus on postmenopausal women, limited evidence also supports use in premenopausal women in their late reproductive years who meet the criteria for HSDD.
Cardiovascular Effects at Normal Levels
One concern women sometimes have is whether testosterone affects heart health. Data from the Rotterdam Study, a large population-based investigation, found no significant association between women’s natural testosterone levels and atherosclerosis in the abdominal aorta, nor did testosterone levels predict whether atherosclerosis progressed over time. At the levels women’s bodies naturally produce, testosterone does not appear to be a cardiovascular risk factor. The heart concerns with testosterone are specific to oral formulations and supraphysiological doses, not the hormone itself at normal concentrations.
How Levels Change With Age
Women’s testosterone peaks in the late teens and twenties, then gradually declines. Normal adult levels for women 18 and older are generally below 40 ng/dL. Unlike estrogen, which drops sharply at menopause, testosterone declines more gradually over decades. By the time a woman reaches her 40s, her testosterone levels may be roughly half what they were at 20. This slow decline is one reason symptoms of low testosterone can creep in without an obvious trigger, making them easy to attribute to stress, aging, or other life changes.