Testosterone is an essential hormone in women, not just a “male hormone.” Women produce it in smaller amounts than men, but it plays a critical role in sex drive, bone strength, muscle maintenance, mood, and brain function. Normal levels for adult women fall below 40 ng/dL of total testosterone, roughly a tenth of what’s typical for men. When those levels swing too high or too low, the effects can be significant.
What Testosterone Does in Women’s Bodies
Testosterone contributes to several systems at once. It acts partly as a building block for estrogen (your body converts some testosterone into estrogen), but it also has independent effects on muscle, bone, the brain, blood vessels, and reproductive tissues.
For bones, testosterone helps maintain density by acting directly on the cells that build and maintain bone tissue. Women in their late reproductive years with lower free testosterone levels experience a statistically significant decline in bone mineral density of more than 1% per year. That may sound small, but compounded over a decade it meaningfully raises fracture risk.
In the brain, testosterone appears to be neuroprotective and has anti-inflammatory effects. Clinical trials in postmenopausal women show improvements in cognitive performance with testosterone supplementation. It also influences mood and energy levels throughout the reproductive years.
Testosterone supports muscle mass and strength. This isn’t about building bulk. It’s about maintaining the baseline muscle tone that keeps you functional, supports your metabolism, and protects your joints.
Testosterone and Sexual Desire
The link between testosterone and libido in women is one of the most studied aspects of this hormone. Testosterone influences spontaneous sexual thoughts, responsiveness to erotic cues, and the ability to maintain interest during sexual activity. When levels drop, particularly after menopause, some women notice a marked decline in desire that goes beyond normal fluctuations.
This persistent loss of desire has a clinical name: hypoactive sexual desire disorder, or HSDD. It’s defined as six or more months of absent or decreased motivation for sexual activity, combined with personal distress such as frustration, sadness, or worry. The key distinction is the distress component. A lower sex drive that doesn’t bother you isn’t a disorder. HSDD is currently the only evidence-based reason doctors prescribe testosterone therapy for women.
Signs of Low Testosterone
There’s no single blood test cutoff that reliably diagnoses low testosterone in women the way there is for men. Instead, the picture is built from symptoms. Common signs include:
- Low sex drive
- Persistent fatigue and lack of energy
- Loss of muscle tone and strength
- Mood changes like depression or anxiety
- Vaginal dryness
- Trouble sleeping
- Thinning hair and dry, brittle skin
- Irregular periods or difficulty conceiving
Many of these overlap with symptoms of low estrogen, thyroid problems, or depression, which is part of why diagnosing low testosterone in women can be complicated. Levels naturally decline with age, dropping through the 30s and 40s and falling further after menopause, so some degree of change is expected.
What Happens When Testosterone Is Too High
Excess testosterone in women, called hyperandrogenism, causes a distinct set of problems. The most visible signs are acne and oily skin, excess body hair on the face, chest, or back (coarse, dark hair rather than fine fuzz), thinning hair on the scalp in a male pattern, and irregular periods. It can also cause infertility.
Polycystic ovary syndrome (PCOS) is by far the most common cause. Roughly 80% to 90% of women with hyperandrogenism have PCOS. The mechanism involves a chain reaction: high levels of luteinizing hormone and insulin push the ovaries to produce more androgens, while elevated insulin simultaneously prevents the liver from making a protein called SHBG that normally binds testosterone and keeps it inactive. The result is more free testosterone circulating in the blood. PCOS isn’t the only possible cause, though. Adrenal gland disorders, certain medications, and other conditions can also raise androgen levels.
Testosterone Therapy for Women
A 2019 international consensus statement from endocrine and gynecology societies worldwide concluded that the only supported use of testosterone therapy in women is treating HSDD, and the data show a moderate therapeutic effect. There is not enough evidence to recommend testosterone for energy, mood, bone protection, or general “anti-aging” purposes, despite marketing claims you may encounter.
The endorsed approach is transdermal application, meaning a gel or cream absorbed through the skin. Transdermal delivery produces the most stable, physiologic blood levels. Injections and implanted pellets are discouraged because they tend to push testosterone to levels far above the normal female range. Oral testosterone is also not recommended because it can worsen cholesterol profiles, lowering HDL (“good” cholesterol) and raising LDL.
Because no testosterone product is currently approved specifically for women in most countries, treatment is prescribed off-label using products designed for men at adjusted doses. The typical starting dose is about one-tenth of a standard male formulation. The cream or gel is applied to the back of the calf, upper outer thigh, or buttock. Compounded testosterone products, which are custom-mixed by specialty pharmacies, lack standardized efficacy and safety data and are not recommended by the consensus guidelines.
Monitoring and Side Effects
Women on testosterone therapy need periodic blood tests to make sure their total testosterone stays within the normal premenopausal range, even if they’re postmenopausal. The goal is to restore physiologic levels, not exceed them. Doctors also watch for signs of androgen excess like acne, unwanted hair growth, or voice deepening.
At physiologic doses, safety data show no serious adverse events. However, long-term safety beyond a few years has not been established. At higher doses, risks include increased red blood cell production (which raises clotting risk), worsening of sleep apnea, and skin reactions. Because treatment is off-label, shared decision-making and informed consent are standard parts of the process.
Why Testosterone Levels Change
Testosterone production in women comes from three sources: the ovaries, the adrenal glands, and conversion from other hormones in tissues like fat and skin. Production peaks in the early 20s and declines gradually, so a 40-year-old woman typically has about half the testosterone she had at 20.
Surgical removal of the ovaries causes an abrupt drop, since the ovaries account for a significant portion of testosterone output even after menopause. Natural menopause produces a more gradual decline. Certain medications, particularly oral contraceptives, can also lower free testosterone by increasing SHBG, the binding protein that takes testosterone out of circulation. Chronic stress, adrenal insufficiency, and pituitary disorders are other potential causes of low levels.
On the flip side, insulin resistance, PCOS, and some adrenal conditions push levels higher. Understanding where your levels fall, and whether your symptoms match, is the starting point for any conversation about treatment.