The most reliable way to check your testosterone is a morning blood draw, ideally before 10 a.m. and preferably while fasting. Most providers order a total testosterone test as the starting point, and if results come back low, you’ll need a second test on a different day to confirm. A single result isn’t enough for a diagnosis.
Types of Testosterone Tests
There are three versions of the test, and each measures something slightly different. About 98% of the testosterone in your blood is bound to proteins, mostly one called SHBG. Only a small fraction floats freely and is immediately available for your body to use.
- Total testosterone measures both the bound and free forms combined. This is the standard first test and the one most providers order.
- Free testosterone measures only the unattached portion. It’s less commonly ordered but can be useful when total testosterone results don’t match your symptoms, or when SHBG levels might be throwing off the picture.
- Bioavailable testosterone measures free testosterone plus the portion loosely bound to a protein called albumin (which can still be used by tissues). This test is rarely ordered but serves a similar role to free testosterone testing.
Free testosterone is often calculated using a formula rather than measured directly. The formula uses your total testosterone, SHBG, and albumin levels. For most people this calculation is accurate enough, but in cases where albumin drops below 3.5 g/dL and SHBG is also low, the math becomes less reliable and a direct measurement may be needed.
When and How to Get Tested
Testosterone follows a daily cycle, peaking in the early morning and dropping throughout the day. Guidelines recommend drawing blood before 10 a.m., or within three hours of waking up, to catch levels near their peak. Testing later in the day can produce artificially low readings that don’t reflect your actual baseline.
Whether you need to fast is a point of some debate. One study found no significant difference between fasting and non-fasting testosterone levels in the same group of men. However, expert guidelines from the Endocrine Society still recommend fasting before the draw, since glucose intake can temporarily suppress testosterone. The safest approach is to skip breakfast and drink only water before your appointment. If you’ve already eaten, the result may still be useful, but your provider might ask you to repeat the test fasting if the number is borderline.
The Endocrine Society is clear that a low testosterone diagnosis requires consistently low results on at least two separate morning tests, combined with symptoms. A single low reading doesn’t confirm anything on its own.
At-Home Testing Kits
At-home kits let you collect a sample (either a finger-prick blood spot or saliva) and mail it to a lab. They’re convenient, but they come with real trade-offs in accuracy.
In a study of men collecting their own finger-prick samples, only 39 out of 59 samples were usable. The rest failed because of contamination from testosterone gel on the skin, improper technique like pressing the finger onto the card instead of letting blood drip naturally, or drops that were too small. Among the usable samples, the correlation with standard lab results was 0.87, which is decent but not perfect.
Saliva tests measure only free testosterone and can be influenced by what you’ve recently eaten or drunk. They’re useful as a screening tool but not considered reliable enough for a clinical diagnosis. If an at-home test flags something concerning, you’ll still need a standard blood draw to confirm it.
How to Prepare the Night Before
Sleep has a measurable effect on testosterone. A meta-analysis found that total sleep deprivation (staying awake 24 hours or more) significantly reduces testosterone levels. Partial sleep restriction, like getting five or six hours instead of eight, did not produce a statistically significant drop. Still, aiming for at least seven hours the night before your test removes one variable from the equation.
Beyond sleep, a few practical steps help ensure your results reflect your true baseline. Avoid heavy alcohol the night before. Schedule the draw as early in the morning as you can. If you use any testosterone gel or cream, wash your hands thoroughly before a finger-prick test, as residue on the skin was the single biggest source of contaminated samples in the at-home testing study.
Understanding Your Results
Most labs report total testosterone in nanograms per deciliter (ng/dL). The commonly cited normal range for adult men falls roughly between 300 and 1,000 ng/dL, though the exact reference range varies slightly between laboratories depending on their equipment and the population they calibrated against. Your lab report will list its specific reference range next to your result.
A number below the lab’s range doesn’t automatically mean you need treatment. Context matters: your age, symptoms, time of day the blood was drawn, whether you fasted, and how you slept all influence the result. Testosterone also naturally declines with age, dropping roughly 1 to 2 percent per year after age 30 in most men. A level that would be flagged as low in a 25-year-old might be typical for a 60-year-old.
If your total testosterone comes back low but your symptoms are mild or absent, your provider may check free testosterone or SHBG to get a clearer picture. Some men have low total testosterone simply because their SHBG is low, meaning less protein is carrying testosterone around, but their free (active) testosterone is perfectly normal. Others have normal total testosterone but high SHBG, leaving less of it available for their body to use. The full picture often requires more than a single number.
Symptoms That Prompt Testing
Most people searching for how to check testosterone are experiencing something that made them wonder. The symptoms that typically lead to testing include persistent fatigue that doesn’t improve with sleep, reduced sex drive, difficulty getting or maintaining erections, loss of muscle mass or strength, increased body fat (especially around the midsection), mood changes like irritability or low motivation, and difficulty concentrating.
None of these symptoms is specific to low testosterone. Every one of them overlaps with conditions like depression, thyroid disorders, poor sleep, or simply the effects of stress. That’s exactly why the diagnostic standard requires both confirmed low levels on blood work and a pattern of symptoms. The blood test gives you an objective number to work with rather than guessing.