The only reliable way to know your testosterone level is a blood test, typically ordered by a doctor or purchased directly from a lab. The standard test measures total testosterone in your blood, and most labs can return results within a few days. But getting an accurate reading depends on when you test, how you prepare, and which type of test you get.
The Blood Test: What’s Actually Measured
Testosterone circulates in your blood in two forms. Most of it is bound to proteins, which means your body can’t readily use it. A smaller portion floats freely and is available to build muscle, maintain bone density, and drive other functions. The most common test measures total testosterone, which combines both bound and free forms into a single number.
A free testosterone test measures only the unbound, usable portion. This test is less commonly ordered but can be helpful when total testosterone results don’t match your symptoms. For example, someone with a normal total level but low free testosterone might still experience symptoms of deficiency. A third option, the bioavailable testosterone test, measures free testosterone plus the loosely bound portion your body can still access. Your doctor will typically start with total testosterone and only move to the other tests if the picture is unclear.
When and How to Get Tested
Testosterone peaks in the early morning and drops throughout the day. In men under 45, levels drawn after 9 AM can be 150 to 200 ng/dL lower than an early-morning sample. That’s enough to turn a normal result into an apparently low one, or vice versa. For men under 45, blood should be drawn between 7 and 9 AM. Men 45 and older show much less daily fluctuation, so testing any time before 2 PM is considered acceptable.
A single test isn’t enough for a diagnosis. Up to 30% of men who test low on their first draw will have a normal result when retested. The American Urological Association recommends two separate morning blood draws before concluding that testosterone is genuinely low. This matters because testosterone fluctuates day to day. Averaging two or three tests reduces the range of variability by 30% to 43%.
Factors That Can Skew Your Results
Several things can temporarily push your testosterone reading up or down, which is why preparation matters. Acute illness is one of the biggest culprits. A respiratory infection alone can drop testosterone by 10 to 30% in young men. If you’re sick, wait until you’ve recovered before testing.
Body weight has a significant and sustained effect. A BMI increase of 4 to 5 points is associated with a testosterone decline equivalent to about 10 years of aging. Exercise temporarily raises testosterone in a way that depends on intensity, duration, and age, so a hard gym session the morning of your test could inflate your numbers. Sleep deprivation lowers testosterone as well. Moderate alcohol intake doesn’t appear to significantly affect levels, but chronic heavy drinking can.
For the most accurate baseline, get tested on a morning when you’ve slept normally, aren’t fighting an illness, and haven’t done intense exercise beforehand.
What the Numbers Mean for Men
The widely used clinical cutoff for low testosterone in men is 300 ng/dL, based on American Urological Association guidelines. But that single threshold doesn’t tell the whole story. A large study of healthy men aged 20 to 44 found that the typical range shifts with age. Men in their early 20s had middle-range levels of 409 to 558 ng/dL, while men in their early 40s clustered around 350 to 473 ng/dL. The age-specific floor for “normal” dropped from about 409 ng/dL at age 20 to 350 ng/dL by age 40.
Numbers alone don’t equal a diagnosis. A testosterone level of 280 ng/dL in a man with no symptoms is treated differently than the same level in someone experiencing fatigue, low sex drive, and muscle loss. The clinical diagnosis requires both a low number and symptoms.
What the Numbers Mean for Women
Women produce far less testosterone, but it still plays a role in energy, bone health, and sex drive. For a 30-year-old woman, the normal range for total testosterone is roughly 15 to 46 ng/dL, with free testosterone between 1.2 and 6.4 pg/mL. These levels decline gradually with age.
High testosterone in women can signal conditions like polycystic ovary syndrome (PCOS). Signs of excess include unusual hair growth on the face, chest, or back, persistent adult acne, thinning hair on the scalp, and irregular or absent periods. Darkened patches of skin, especially in body folds, can indicate the insulin resistance that often accompanies PCOS. If you’re experiencing several of these symptoms, a testosterone blood test is one of the first steps in evaluation.
Symptoms That Suggest Low Testosterone in Men
Some men with low testosterone have no noticeable symptoms at all. Others experience a combination that can be easy to dismiss individually but forms a recognizable pattern together: reduced sex drive, difficulty getting or maintaining erections, increased body fat (particularly around the midsection), loss of muscle size and strength, fatigue, trouble concentrating, depressed mood, and sleep problems. Bone loss is another consequence, though it typically doesn’t cause symptoms until a fracture occurs.
None of these symptoms are unique to low testosterone. Depression, poor sleep, and low energy have many causes. That’s exactly why the blood test matters: it separates testosterone-related problems from other explanations.
Home Test Kits vs. Lab Blood Draws
Home testosterone kits, usually saliva-based, have become widely available. Saliva testosterone correlates reasonably well with free testosterone in men (a correlation of 0.71), but the relationship is weaker in women (0.39). Saliva tests reflect free testosterone more than total testosterone, and collection method matters. Swab-based collection devices tend to absorb testosterone and give unreliable readings. The passive drool technique is more accurate, but not all home kits use it.
A clinical blood draw remains the gold standard. It gives you total, free, or bioavailable testosterone depending on what’s ordered, with well-established reference ranges. If a home saliva test comes back concerning, you’ll still need a blood test to confirm it.
Cost and Access
You can get a testosterone test through your doctor, who will order a lab draw covered (or partially covered) by insurance if there’s a clinical reason. Without insurance, direct-to-consumer options are available. Labcorp, for instance, offers a comprehensive testosterone panel for $159 out of pocket, no prescription needed. Many similar services exist at comparable prices. You order online, visit a local lab for the blood draw, and get results electronically.
If you go the direct-to-consumer route, choose a test that measures total testosterone from a blood sample, schedule the draw for early morning, and plan to retest if the first result comes back low. A single number from a single morning is a starting point, not an answer.