For adult men, a normal total testosterone level falls between 270 and 1,070 nanograms per deciliter (ng/dL). For adult women, the normal range is below 40 ng/dL. These ranges are wide, and where you fall within them depends on your age, the time of day your blood was drawn, and the specific lab that processed your sample.
Normal Ranges for Men
The broadly accepted reference range for total testosterone in adult men is 270 to 1,070 ng/dL. That’s a huge spread, and most men cluster somewhere in the middle rather than at the extremes. The American Urological Association uses 300 ng/dL as the clinical cutoff: below that level, combined with symptoms, is considered low testosterone (sometimes called “low T” or hypogonadism).
Testosterone peaks in the late teens and early twenties, then gradually declines. Most men lose roughly 1% of their total testosterone per year starting around age 30. A 25-year-old and a 60-year-old can both have “normal” results, but the younger man’s number will typically sit higher in the range. Lab reference ranges don’t always break this down by decade, so a result of 350 ng/dL might be unremarkable for a 65-year-old but worth investigating in a 28-year-old.
Normal Ranges for Women
Women produce testosterone too, just in much smaller amounts. The normal level for adult women (ages 18 and older) is less than 40 ng/dL. During childhood and puberty the numbers fluctuate: girls under one year old can have up to 21 ng/dL, and during the 11-to-17 age window, levels may reach as high as 79 ng/dL before settling into the adult range.
The most common reason a woman’s testosterone rises above normal is polycystic ovary syndrome (PCOS). Elevated testosterone in women can contribute to acne, excess facial or body hair, irregular periods, and difficulty conceiving. If your lab results come back above 40 ng/dL, your provider will likely look into hormonal conditions as a next step.
Total vs. Free Testosterone
When you get a testosterone blood test, the standard measurement is total testosterone. This includes all the testosterone circulating in your blood, most of which is bound to proteins and unavailable for your body to use. A smaller fraction circulates unbound, called free testosterone, and this is the portion that actively affects your tissues.
The normal range for free testosterone in men is roughly 50 to 200 picograms per milliliter (pg/mL). Sometimes total testosterone looks normal on paper, but free testosterone is low, which can still produce symptoms. If your total testosterone is borderline or your symptoms don’t match your numbers, your provider may order a free testosterone test to get a more complete picture.
Why the Time of Day Matters
Testosterone follows a daily rhythm. Levels peak between 7:00 and 10:00 in the morning, then drop through the afternoon and evening. In younger men (ages 30 to 40), morning levels can be 30 to 35% higher than late-afternoon levels. That’s a significant swing, enough to push a borderline result from “low” to “normal” depending on when the blood draw happens.
This daily fluctuation shrinks with age. By 70, the difference between morning and afternoon testosterone is only about 10%. Still, guidelines recommend testing before 10:00 a.m. (or within three hours of waking) for the most reliable result. Testing should also happen on a day when you’re feeling well and your sleep schedule has been stable, since acute illness, jet lag, or shift changes can temporarily throw off your levels. A fasting blood draw is preferred.
Because day-to-day variation is real, a diagnosis of low testosterone requires two separate morning blood draws on different days, both showing levels below 300 ng/dL.
What Low Testosterone Feels Like
Numbers only tell part of the story. Low testosterone becomes a medical concern when it’s paired with symptoms. The earliest signs in adult men tend to be reduced sex drive, low energy, and depressed mood. Over time, more noticeable changes can develop: difficulty getting or maintaining erections, loss of muscle mass, less facial and body hair, increased body fat, and growth of breast tissue.
Severe or prolonged low testosterone can also cause bone loss (osteoporosis), fertility problems, trouble concentrating, and hot flashes. These symptoms overlap with many other conditions, which is why the blood test is essential for confirmation rather than relying on symptoms alone.
Risks of Abnormally High Testosterone
Having too much naturally occurring testosterone is rare in men. Most cases of abnormally high levels come from external sources like anabolic steroids or testosterone supplements. The side effects are counterintuitive: artificially elevated testosterone can actually lower sperm counts, shrink the testicles, and cause erectile dysfunction. It also raises the risk of blood clots, heart problems, liver disease, high blood pressure, and high cholesterol. Acne, fluid retention, weight gain, insomnia, mood swings, and impaired judgment are common as well.
In adolescents, excess testosterone from external sources can stunt growth by causing bone growth plates to close prematurely.
Factors That Can Lower Your Levels
Beyond aging, several lifestyle factors influence where your testosterone sits within the normal range. Total sleep deprivation (staying awake for 24 hours or more) significantly reduces testosterone levels in healthy men. Partial sleep loss, like getting a few fewer hours than usual for a night or two, doesn’t appear to have as dramatic an effect, but chronically short sleep adds up over time.
Obesity has a well-documented negative relationship with testosterone. Excess body fat, particularly around the midsection, promotes the conversion of testosterone into estrogen, which drives levels down further. Diabetes and metabolic syndrome are similarly linked to lower testosterone. Losing weight, improving sleep quality, and managing blood sugar are among the most effective non-medical ways to support healthy testosterone levels.
Acute illness and hospitalization can also temporarily suppress testosterone, which is why guidelines specify that testing should only happen when you’re clinically well. A low reading during a bout of flu or after surgery doesn’t necessarily reflect your baseline.