Testosterone is tested with a simple blood draw, typically done in the morning between 7 and 10 a.m. when your levels are naturally at their highest. The procedure takes less than five minutes, but the timing, preparation, and type of test your provider orders all affect how useful the results are.
Why Morning Testing Matters
Testosterone follows a daily rhythm. Levels peak in the early morning, dip to their lowest point in the evening, then start climbing again overnight. In younger men (ages 30 to 40), morning testosterone runs 30 to 35 percent higher than levels measured in the mid to late afternoon. That’s a significant swing, and it means a test drawn at 3 p.m. could look like a problem when your actual peak levels are perfectly normal.
Current guidelines recommend drawing blood between 8 and 9 a.m. to minimize the effect of this natural fluctuation. If your result comes back low, your provider will almost certainly want to repeat the test on a separate morning before making any diagnosis. A single low reading isn’t enough. The Endocrine Society’s guidelines require “unequivocally and consistently low” levels on repeated morning fasting draws before diagnosing testosterone deficiency.
How the Blood Draw Works
A healthcare professional draws blood from a vein in your arm using a standard needle. A small amount goes into a tube, the needle comes out, and a bandage goes on. The whole thing is over in under five minutes. You may need to fast for several hours beforehand (water is fine), and you should tell your provider about any medications or supplements you’re taking, since many can shift your results up or down.
Total Testosterone vs. Free Testosterone
Most providers start with a total testosterone test. This measures everything in your blood: both the testosterone that’s freely circulating and the testosterone bound to proteins. The normal range for adult males is roughly 193 to 824 ng/dL, though exact reference ranges vary by lab.
Here’s the catch. Most of your testosterone is bound to a protein called sex hormone-binding globulin (SHBG), and bound testosterone can’t actually interact with your tissues. Only free testosterone does the work of building muscle, maintaining bone density, and supporting reproductive health. So it’s possible to have a normal total testosterone number while the amount your body can actually use is too low or too high.
If your total testosterone comes back normal but you still have symptoms, your provider may order an SHBG test or a free testosterone measurement. High SHBG means more of your testosterone is locked up and unavailable. Low SHBG means more is free and active. This second layer of testing helps explain why some people with “normal” results still feel off, and why others with borderline low totals feel fine.
Medications That Can Skew Results
A long list of common medications can raise or lower your testosterone levels, which is why your provider needs to know what you’re taking before interpreting results. Opioids (including long-term pain medications), corticosteroids, and certain anti-seizure drugs can lower testosterone. Finasteride, which is widely used for hair loss, can raise it. Anabolic steroids suppress your body’s natural production and will dramatically alter readings.
These aren’t false readings in the sense that the lab made an error. The medications genuinely change your hormone levels. But if your provider doesn’t know you’re on one of them, they might misinterpret the result as a problem that needs treatment when it’s actually a side effect of something you’re already taking.
At-Home Testing Kits
You can buy at-home testosterone test kits that use either a blood spot (finger prick) or a saliva sample, which you mail to a lab. These are convenient if you want a general sense of where your levels fall, but they come with real limitations.
Saliva-based tests measure only free testosterone and are sensitive to contamination. Tiny amounts of blood from your gums can leak into saliva and throw off results. Storage conditions, the materials used to collect the sample, and even stimulating saliva production with citric acid can alter readings. Research has also found that the relationship between salivary and blood testosterone differs between men and women, adding another layer of complexity to interpretation. Saliva testing has a solid place in research settings, particularly in sports science for tracking hormonal responses to training, but it’s less reliable for individual clinical decisions.
If an at-home test suggests something is off, you’ll still need a standard morning blood draw through your provider to confirm the finding and get the full picture including total testosterone, free testosterone, and SHBG if needed.
What Happens After Testing
A single blood draw gives your provider a starting point. If your total testosterone is within the normal range and you have no symptoms, the story usually ends there. If it’s low, you’ll repeat the test on a different morning while fasting to confirm. Your provider may also check other hormones (like those produced by the pituitary gland) to figure out why levels are low, since the cause determines the treatment approach.
Keep in mind that reference ranges are wide. A 25-year-old at 250 ng/dL is in a very different situation than a 70-year-old at the same number, even though both technically fall within the “normal” range. Context matters: your age, symptoms, and overall health all factor into how your provider reads the result. The number on the lab report is a piece of the puzzle, not the whole picture.