High testosterone results from your body either producing too much of the hormone or failing to regulate what’s already circulating. In adults, normal testosterone ranges from 193 to 824 ng/dL for males and below 40 ng/dL for females. When levels climb above those thresholds, the cause could be anything from a hormonal condition like PCOS to a tumor, a genetic enzyme deficiency, or even how your liver handles a protein that controls hormone availability.
PCOS: The Most Common Cause in Women
Polycystic ovary syndrome is by far the leading reason women have elevated testosterone. The connection runs through insulin. In PCOS, the body becomes resistant to insulin, meaning cells don’t respond to it normally. To compensate, the pancreas pumps out more. That excess insulin doesn’t just affect blood sugar. It acts directly on the ovaries and adrenal glands through its own receptor, stimulating them to ramp up androgen production.
The biochemistry is revealing: insulin resistance and excess androgen production may share a single underlying mechanism. A chemical modification called serine phosphorylation can simultaneously impair the insulin receptor (causing insulin resistance) and activate a key enzyme in androgen production (boosting testosterone output). This means the two hallmark features of PCOS, insulin resistance and high androgens, may stem from the same genetic glitch rather than one simply causing the other. Insulin also appears to increase pituitary release of luteinizing hormone, which further drives the ovaries to produce testosterone.
Congenital Adrenal Hyperplasia
Congenital adrenal hyperplasia (CAH) is a genetic condition where the adrenal glands lack one of the enzymes needed to produce cortisol. The most common form involves a missing enzyme called 21-hydroxylase. Without it, the raw materials that would normally become cortisol get rerouted into androgen production instead. The result is excess testosterone starting from birth, though a milder “non-classic” form can go undiagnosed until puberty or adulthood, when symptoms like acne, irregular periods, or excess body hair prompt testing.
CAH affects both sexes. In males, it frequently causes testicular adrenal rest tumors, benign growths of adrenal-like tissue inside the testes, with an average prevalence around 40% of male CAH patients. These tumors are the most common cause of infertility in men with CAH. Adrenal rest tissue can also appear in the pelvis, kidneys, ovaries, and even near the spinal cord in people without CAH, though this is less common.
Tumors That Produce Androgens
Certain tumors act like miniature hormone factories, churning out testosterone or its precursors independent of the body’s normal feedback systems. In the testes, Leydig cell tumors are the classic culprit. These tumors arise in the cells responsible for testosterone production and can push levels far above normal. Distinguishing them from the adrenal rest tumors seen in CAH is clinically difficult because the two look similar on imaging and under a microscope.
In the adrenal glands, both benign adenomas and malignant carcinomas can secrete androgens. Adrenal tumors sometimes produce cortisol or aldosterone as well, leading to overlapping hormonal syndromes. Ovarian tumors, particularly certain stromal tumors, can also drive testosterone levels up dramatically in women. Tumor-driven testosterone elevation tends to come on rapidly and reach very high levels, which helps distinguish it from slower-developing conditions like PCOS.
Low SHBG: More Active Testosterone From the Same Supply
Your total testosterone level doesn’t tell the whole story. Most testosterone in the blood is bound to a protein called sex hormone-binding globulin (SHBG), produced mainly by the liver. Bound testosterone is essentially inactive: it can’t enter your tissues and do anything. Only the unbound, “free” fraction works on your cells. So even if your total testosterone is normal, low SHBG means a larger share of that testosterone is free and active, producing the same effects as genuinely elevated production.
Several conditions lower SHBG. An underactive thyroid (hypothyroidism) reduces it, as does obesity, type 2 diabetes, and metabolic syndrome. These conditions overlap considerably with PCOS, which is why women with PCOS often face a double hit: their ovaries produce more testosterone, and lower SHBG leaves more of it active. In men, low SHBG from metabolic conditions can push free testosterone into a range that causes symptoms even when total testosterone looks unremarkable on a lab report.
Anabolic Steroids and Supplements
Exogenous testosterone, whether injected, applied as a gel, or taken as anabolic steroids, is a straightforward and increasingly common cause of high levels. Testosterone replacement therapy prescribed for low levels can overshoot the target range if dosing isn’t monitored carefully. Anabolic steroid use for bodybuilding or athletic performance pushes levels well beyond physiological norms.
Some over-the-counter supplements marketed as “testosterone boosters” contain ingredients like DHEA, a precursor hormone that the body can convert into testosterone. While most of these supplements have modest effects at best, DHEA in particular can raise androgen levels meaningfully in women, whose baseline is much lower. Any unexplained testosterone elevation should prompt an honest conversation about supplements, since many users don’t think of them as hormonal products.
Exercise and Short-Term Spikes
Heavy resistance training temporarily raises testosterone, but the magnitude and duration depend on how you structure the workout. Lifting at high intensity using large muscle groups with rest intervals around two minutes produces a significant post-exercise testosterone spike that remains elevated for about 30 minutes into recovery. Shorter rest periods of 60 or 90 seconds, interestingly, don’t produce the same statistically significant rise. These transient bumps are a normal physiological response and don’t indicate a hormonal disorder. They typically don’t push levels outside the reference range on a standard blood test, especially since labs usually draw blood in the morning when testosterone is naturally at its peak.
Other Medical Causes
Cushing’s syndrome, where the body produces too much cortisol, can disrupt the entire adrenal hormone cascade and raise androgen levels as a secondary effect. Thyroid disorders affect testosterone indirectly through their influence on SHBG. Growth hormone excess (acromegaly) and certain pituitary abnormalities can also alter the signaling pathways that regulate testosterone production.
Liver disease deserves special mention because it disrupts SHBG in complex ways. While advanced liver disease can actually raise SHBG (potentially lowering free testosterone), earlier stages and specific liver conditions can impair the organ’s ability to clear hormones from the blood, leading to hormonal imbalances that vary from person to person.
Signs of High Testosterone
The symptoms differ significantly between sexes. In women, excess testosterone commonly causes acne and oily skin, coarse dark hair on the upper lip, chin, chest, abdomen, or back (hirsutism), irregular or absent periods, thinning hair on the scalp in a pattern resembling male baldness, and difficulty getting pregnant. In more severe cases, particularly from tumors or high-dose steroid exposure, the clitoris may enlarge and the voice may deepen.
In men, the picture is less obvious. High testosterone from adrenal sources usually doesn’t produce dramatic outward symptoms. The main concern is its effect on the testes: excess androgens from outside the normal testicular pathway suppress the brain’s signals to the testes, which can shrink them and impair sperm production. This is why men using anabolic steroids, despite sky-high testosterone levels, often develop fertility problems. In boys who haven’t yet reached puberty, elevated testosterone triggers premature development: early pubic and armpit hair, a deepening voice, and accelerated growth that may ultimately result in shorter adult height as growth plates close too soon.
How Levels Are Tested
A standard blood draw measures total testosterone, but your provider may also order free testosterone and SHBG levels to get the full picture. Reference ranges vary between laboratories and testing methods, so a result that’s flagged as high at one lab might fall within range at another. Morning draws are standard because testosterone follows a daily rhythm, peaking in the early hours and declining through the afternoon. If your first result comes back elevated, a repeat test on a different day confirms the finding before any workup begins.
From there, the direction of investigation depends on the suspected cause. Imaging of the ovaries, adrenals, or testes may follow. Additional hormone panels, including cortisol, DHEA-S, and insulin levels, help narrow whether the source is ovarian, adrenal, or metabolic. In cases where CAH is suspected, a specific test measuring a cortisol precursor called 17-hydroxyprogesterone can confirm the diagnosis.