The most common cause of high testosterone in women is polycystic ovary syndrome (PCOS), which accounts for the majority of cases. But several other conditions, from adrenal gland disorders to thyroid problems, can also push testosterone levels above normal. Understanding which cause is behind your levels matters because the treatment path looks different for each one.
Normal total testosterone in women under 50 falls around 25 ng/dL or higher, while women over 50 typically sit at 20 ng/dL or above. When levels climb significantly past these thresholds, the effects show up as acne, excess facial or body hair, thinning hair on the scalp, irregular periods, or difficulty getting pregnant.
PCOS: The Leading Cause
Polycystic ovary syndrome drives high testosterone in roughly 70 to 80 percent of women with androgen excess. The condition involves a feedback loop between insulin, the brain’s hormonal signaling center, and the ovaries that keeps testosterone production abnormally high.
Here’s what happens at the biological level. When your body becomes resistant to insulin, your pancreas pumps out more of it to compensate. That excess insulin acts directly on the ovaries, stimulating the cells responsible for making androgens (the family of hormones that includes testosterone) to ramp up production. At the same time, high insulin suppresses a protein made by the liver called sex hormone-binding globulin (SHBG). SHBG normally binds to testosterone and keeps it inactive. With less SHBG in circulation, more testosterone is “free” and active in your body, amplifying the effects even if total testosterone isn’t dramatically elevated.
The brain adds to the problem. In PCOS, the hypothalamus releases its hormonal signals at an abnormally fast rate, which causes the pituitary gland to produce too much luteinizing hormone (LH). LH tells the ovaries to make more androgens. This combination of insulin-driven and brain-driven overproduction is why PCOS can be so persistent and why treatment often targets insulin resistance alongside the hormonal symptoms.
A PCOS diagnosis requires two out of three criteria: signs of high androgens (either visible symptoms or elevated blood levels), irregular or absent periods, and polycystic-appearing ovaries on ultrasound. Updated 2023 international guidelines now also allow a blood test measuring anti-Müllerian hormone (AMH) as an alternative to ultrasound in adults.
Adrenal Gland Disorders
Your adrenal glands, which sit on top of your kidneys, produce a significant share of your body’s androgens. Two adrenal conditions commonly cause elevated testosterone in women.
Non-Classic Congenital Adrenal Hyperplasia
This genetic condition affects about 1 in 1,000 Caucasian women and is far more common in certain ethnic groups: roughly 1 in 27 Ashkenazi Jewish women, 1 in 53 Hispanic women, and 1 in 62 women of Yugoslav descent carry the condition. Unlike the classic form detected at birth, the non-classic version often goes undiagnosed until puberty or adulthood, when symptoms like excess hair growth, acne, and irregular periods appear. It’s caused by a partial deficiency in an enzyme the adrenal glands need to make cortisol. When cortisol production is sluggish, the adrenals work overtime, and excess androgens spill out as a byproduct.
Because its symptoms overlap almost entirely with PCOS, non-classic congenital adrenal hyperplasia is frequently misdiagnosed. A specific blood test measuring a hormone precursor called 17-hydroxyprogesterone can help distinguish the two. If that value is borderline, a stimulation test and sometimes genetic testing confirm the diagnosis.
Adrenal Tumors and Cushing’s Syndrome
Less commonly, a tumor on the adrenal gland can independently produce androgens, sometimes causing testosterone to spike dramatically. Cushing’s syndrome, where the body makes too much cortisol (often due to a pituitary or adrenal tumor), can also raise androgen levels. These conditions tend to cause more severe or rapidly progressing symptoms compared to PCOS, which is one clinical clue that something beyond PCOS may be going on.
How Thyroid Problems Raise Free Testosterone
An underactive thyroid doesn’t directly tell your ovaries to make more testosterone, but it changes how much testosterone is available to act on your tissues. Thyroid hormones stimulate the liver to produce SHBG, the protein that binds testosterone and keeps it inactive. When thyroid hormone levels drop, SHBG production falls with it. The result: your total testosterone may look normal on a blood test, but your free (active) testosterone climbs because less of it is being bound up.
This mechanism is one reason clinicians now recommend measuring both total and free testosterone when evaluating androgen excess. A woman with untreated hypothyroidism might have completely normal total testosterone but elevated free testosterone, and her symptoms (hair changes, acne, irregular cycles) would be real. Correcting the thyroid problem often resolves the androgen imbalance without any additional hormonal treatment.
Medications That Raise Testosterone
Several categories of medication can elevate androgen levels in women:
- Anabolic-androgenic steroids, sometimes used for bodybuilding or prescribed for certain medical conditions, directly introduce androgens into the body.
- Certain synthetic progestins found in some older birth control formulations have androgenic activity, meaning they can bind to the same receptors as testosterone and produce similar effects.
- Some antiseizure medications can alter hormone metabolism in ways that increase circulating androgens or decrease SHBG.
If your testosterone levels rose after starting a new medication, that timing is worth mentioning to your healthcare provider. Switching to an alternative drug often resolves the problem.
Ovarian Tumors and Other Rare Causes
Androgen-secreting ovarian tumors are uncommon but important to recognize. They typically cause a rapid onset of symptoms over weeks to months rather than the gradual progression seen with PCOS. Testosterone levels in these cases tend to be very high, sometimes reaching into the range normally seen in men. Rapidly deepening voice, sudden increase in muscle bulk, or clitoral enlargement are red flags that point toward a tumor rather than a metabolic cause.
Obesity also contributes independently of PCOS. Fat tissue is metabolically active and influences hormone levels in multiple ways, including increasing insulin resistance (which suppresses SHBG) and converting certain hormones into androgens. Losing even a modest amount of weight, around 5 to 10 percent of body weight, can measurably reduce testosterone levels in women with androgen excess.
Getting Accurate Test Results
Testosterone levels in women fluctuate throughout the menstrual cycle and throughout the day, so timing your blood draw matters. Research shows the most reliable and reproducible testosterone and free androgen measurements come from blood drawn around the middle of the cycle, roughly days 12 through 16. Morning draws between 8:30 a.m. and noon are standard because testosterone peaks in the early morning hours.
Current guidelines recommend that labs use a highly accurate testing method called liquid chromatography-tandem mass spectrometry for measuring total testosterone. Older immunoassay methods, still used in some labs, are less precise at the lower concentrations typical in women and can produce misleading results. If your numbers seem inconsistent with your symptoms, asking whether your lab used mass spectrometry is a reasonable question.
Both total testosterone and free testosterone should be measured. Total testosterone alone can miss cases where SHBG is low, since more testosterone is active even when the total amount looks normal. Free testosterone can be estimated using a calculation called the free androgen index, which factors in SHBG levels. If neither testosterone nor free testosterone is elevated but symptoms are clearly present, testing for two other androgens, androstenedione and DHEA-S, can sometimes identify the source, though these markers are less specific and DHEA-S naturally declines with age.