For adult men aged 19 and older, the normal range for total testosterone is 300 to 1,000 ng/dL. That range stays the same on paper regardless of age, but actual averages shift downward as men get older, with levels dropping roughly 1% per year after age 40. Where you fall within that range depends on your age, body composition, time of day, and how the test was done.
Normal Testosterone Ranges for Adults
The standard reference range for total testosterone in adult men is 300 to 1,000 ng/dL. This is the range most labs use, and it applies broadly to all men 19 and older. Women have much lower levels, with a normal range of less than 40 ng/dL throughout adulthood.
These ranges are intentionally wide because there’s enormous natural variation between individuals. A 25-year-old man at 450 ng/dL and a 25-year-old man at 900 ng/dL can both be perfectly healthy. What matters clinically is whether your level falls below 300 ng/dL and whether you have symptoms to go along with it.
How Testosterone Changes With Age
Testosterone peaks in the late teens and early twenties, then holds relatively steady through the thirties. After age 40, levels decline by about 1% per year on average. That means a man who starts at 600 ng/dL at age 40 might naturally drop to around 480 ng/dL by age 60, all without any disease or disorder.
This gradual decline is sometimes called “andropause” or “male menopause,” though the comparison to female menopause is misleading. Women experience a dramatic hormone drop over a few years. Men experience a slow, steady slide that may or may not cause noticeable symptoms. Many men maintain levels well within the normal range into their seventies and eighties.
Total vs. Free Testosterone
Most testosterone in your blood is bound to proteins, primarily one called sex hormone-binding globulin. Only a small fraction circulates freely and is available for your body to use. That’s why doctors sometimes order a “free testosterone” test alongside the total number. The normal free testosterone range for adult men is 52 to 280 pg/mL (picograms per milliliter, a much smaller unit than ng/dL).
Free testosterone can be especially useful in borderline cases. A man might have a total testosterone of 350 ng/dL, which looks fine, but a low free testosterone level because more of it is bound up and unavailable. This is more common as men age, since the binding protein tends to increase over time, effectively reducing the testosterone your body can actually use even when the total number looks adequate.
Why Time of Day Matters
Testosterone follows a daily rhythm, peaking in the early morning and dropping through the afternoon. In men younger than 45, studies show mean levels around 600 ng/dL at 7 a.m., dropping to about 500 ng/dL by 10 a.m., and falling to 400 to 450 ng/dL by 2 p.m. That’s a potential 25 to 30% swing from morning to afternoon in the same person on the same day.
This is why guidelines call for testing between 7 and 10 a.m. A blood draw at 3 p.m. could show a result that looks low but actually reflects normal afternoon levels. If you’ve had a testosterone test done in the afternoon that came back borderline, a morning retest may tell a different story.
Body Weight Has a Bigger Impact Than You’d Expect
Age gets most of the attention when people think about declining testosterone, but body weight may actually matter more. A study of over 1,600 men aged 40 and older found that each one-point increase in BMI was associated with a 2% decrease in testosterone. For a man with a BMI of 30 compared to a man with a BMI of 25, that’s roughly a 10% difference in levels at the same age.
Waist circumference turns out to be an even stronger predictor than BMI. Research involving over 1,800 men found that a four-inch increase in waist size raised the odds of having low testosterone by 75%. For comparison, ten years of aging only raised those odds by 36%. In other words, carrying extra weight around the midsection can suppress testosterone more than a full decade of natural aging. Australian research found that nearly one in seven obese men had testosterone levels low enough to potentially benefit from treatment, a rate more than four times higher than in men at a healthy weight.
What Counts as “Low” Testosterone
The American Urological Association uses 300 ng/dL as the cutoff for low testosterone. Other medical organizations around the world use slightly different thresholds, ranging from 230 to 350 ng/dL. But a number below 300 on a single blood test does not automatically mean you need treatment.
A formal diagnosis of hypogonadism (the clinical term for low testosterone) requires two things: at least two early morning blood tests showing levels below the cutoff, and the presence of symptoms. Those symptoms can include reduced sex drive, erectile dysfunction, loss of spontaneous erections, decreased energy, reduced muscle mass, breast tenderness, difficulty concentrating, depressed mood, or hot flashes in severe cases. A low number without symptoms, or symptoms without a confirmed low number, doesn’t meet the diagnostic bar.
Why Lab Results Vary
If you’ve had testosterone tested at two different labs and gotten noticeably different numbers, you’re not imagining things. Different laboratories use different testing methods, and results can vary meaningfully between them. The CDC runs a Hormone Standardization Program specifically to improve accuracy and consistency across labs, working to calibrate testing methods against a gold-standard reference measurement. But standardization is still a work in progress, and your results are always interpreted against the specific reference range printed on your lab report, not a universal number.
This is one reason why retesting at the same lab matters if your doctor is tracking changes over time. Comparing a result from one lab’s method to another lab’s method can create the illusion of a rise or drop that isn’t real.
Testosterone Ranges for Women
Women produce testosterone too, just in much smaller amounts. The normal range for adult women across all ages (18 to 99) is less than 40 ng/dL. While testosterone plays a role in female sex drive, bone density, and muscle maintenance, the clinical significance of small variations within that range is less well established than it is for men. Normal free testosterone for adult women is 1.1 to 6.3 pg/mL.