Normal testosterone levels by age

A normal total testosterone level for a healthy young man is roughly 264 to 916 ng/dL, according to the largest effort to standardize the measurement across labs. Levels then drift down slowly with age, by about 1% to 2% a year in men over 40. Clinicians usually start to consider low testosterone below 300 ng/dL, but only with symptoms and only after repeat morning tests. Here is what the numbers mean, and why a single result rarely settles the question.

The normal range, and where it comes from

Testosterone assays used to disagree from lab to lab. In 2017, researchers working with the CDC measured samples from four large cohorts, 9,054 community-dwelling men in the United States and Europe, against a reference method, then converted every cohort to the same scale (Travison et al.). For healthy nonobese men aged 19 to 39, the harmonized percentiles were:

The authors call 264 to 916 ng/dL the harmonized normal range for that group. They also found that age-specific levels in nonobese men were higher than in all men, so body weight shifts the numbers too. Your lab may print a slightly different range, because each lab sets its own. Read your result against the range on your report.

How testosterone changes with age

The best long-term data come from the Massachusetts Male Aging Study, which tested 1,709 men aged 40 to 70 in 1987 to 1989 and followed 1,156 of them for 7 to 10 years. It measured the decline two ways:

Sex hormone-binding globulin (SHBG), the protein that carries testosterone in the blood, rose about 1.6% a year across age groups, while free testosterone fell faster than total testosterone.

Health mattered. Men without chronic illness, prescription medicines, obesity or heavy drinking had levels of several androgens 10% to 15% higher. The decline within men was steeper than the difference between age groups, which the authors read as a sign that new illness may speed up the drop.

What this means in practice: the harmonized study derived age-specific values, but its headline normal range is the one for men aged 19 to 39, and labs print their own reference ranges. Ask whether your lab’s range is adjusted for age, and track your own results over time rather than comparing them with a single chart.

Total vs free testosterone

Most tests report total testosterone: the hormone bound to SHBG, the hormone loosely bound to albumin, and the small free fraction together. Free and albumin-bound testosterone are the parts tissues can use, which is why some reports also show “bioavailable” or free testosterone.

Total testosterone is the starting point. The Endocrine Society recommends measuring free testosterone when total testosterone is near the lower limit of normal, or when a condition changes SHBG, using equilibrium dialysis or an accurate formula. In the Massachusetts study, free testosterone fell faster with age than total testosterone, so an older man with a borderline total can have a clearly low free level. Ask your clinician which number your plan is based on.

What else moves the number

Age is only one factor. In the Massachusetts study, men without chronic illness, prescription medicines, obesity or heavy drinking had androgen levels 10% to 15% higher, and the harmonized study found higher levels in nonobese men than in men overall. The Endocrine Society recommends looking for the cause once low testosterone is confirmed, because treating that cause can matter as much as the number. If your result is low, expect questions about your weight, sleep, medicines and other conditions before any prescription.

The cut-offs clinicians use

Below 300 ng/dL

The AUA guideline uses a total testosterone below 300 ng/dL as a reasonable cut-off for diagnosing low testosterone, alongside symptoms and signs. TRAVERSE, the largest heart-safety trial of testosterone, enrolled men with two fasting levels below 300 ng/dL and adjusted doses to keep them between 350 and 750 ng/dL (Lincoff et al.).

Two morning tests

FDA labels set a firm rule before any prescription. The Depo-Testosterone label says to confirm hypogonadism with serum testosterone measured in the morning on at least two separate days, with both results below the normal range. The Endocrine Society guideline adds fasting, an accurate assay and a repeat test to confirm. When total testosterone is near the lower limit, or SHBG is likely to be abnormal, it recommends measuring free testosterone too.

Normal ranges in drug trials

Each FDA label defines “normal” for its own study, using its own assay. The numbers below aren’t comparable with each other or with your lab report, but they show why a single cut-off doesn’t exist:

Age-related low testosterone and the labels

Every testosterone label we checked, including Depo-Testosterone, AndroGel 1.62%, Kyzatrex and Jatenzo, still states that safety and efficacy in men with “age-related hypogonadism” have not been established. In plain terms, the FDA approved testosterone for men whose low levels have a medical cause, such as testicular failure or a pituitary problem, and hasn’t approved it for the gradual decline that comes with age. Clinicians can still prescribe it, but it is a judgment call to discuss with yours, weighing your symptoms, your numbers and your risks.

Some online clinics set their own age limits. Henry Meds, for example, treats men aged 35 to 65 whose lab results meet its criteria.

Getting your level tested

If you want a number, get a morning blood test, ideally fasting, and repeat it if it comes back low. Several online clinics start with one: Hims mails a lab kit, Hone Health offers an at-home or partner-lab test for $65 with a physician consult, and Rex MD sends you to Labcorp or Quest for $99 with a video visit, as of October 2026. See clinics with at-home tests and how to get TRT online.

Bring your symptoms to the conversation. The Endocrine Society recommends diagnosing low testosterone only in men with symptoms and signs and consistently low levels, so a low number with no symptoms, or symptoms with a normal number, usually calls for more testing rather than a prescription.

If your level is low

Treatment options include testosterone injections, gels and creams, oral capsules and, for some men with secondary hypogonadism, enclomiphene, which raises your own production. Testosterone is a Schedule III controlled substance, and online prescribing without an in-person exam depends on a DEA rule that runs through December 31, 2026. Compare clinics on our testosterone hub.

The bottom line

For healthy men aged 19 to 39, normal total testosterone runs about 264 to 916 ng/dL, and it falls about 1% to 2% a year after 40, faster for free testosterone. Below 300 ng/dL with symptoms, confirmed on two morning tests, is the usual threshold for a treatment discussion. Read your result against your own lab’s range, and talk it through with a licensed clinician.