Free Testosterone Test: What It Measures and Why It Matters
Most testosterone in your blood is bound to proteins. Free testosterone is the small, unbound part your tissues can use right away.
What the Free testosterone test measures
Unbound (free) testosterone
In our expanded panels it’s calculated from total testosterone, SHBG and albumin, a widely used method
Why we check it at Serene
Two people with the same total testosterone can feel very different, because the amount of binding protein (SHBG) differs. Free testosterone helps explain symptoms when total testosterone is borderline or SHBG is unusually high or low.
At Serene Med Spa in Barboursville, West Virginia, every hormone and wellness plan starts with Labcorp lab work reviewed by a board-certified physician.
What your results can mean
Higher than normal
High free testosterone can come from treatment, low SHBG (often seen with insulin resistance or excess weight) or, in women, conditions like PCOS.
Lower than normal
Low free testosterone with symptoms can point to testosterone deficiency even when total testosterone looks normal, especially when SHBG is high.
Normal ranges vary by lab, age and sex. Your physician reads every result together with your symptoms, history and other tests.
How to prepare
Drawn in the morning with total testosterone. If you take biotin (vitamin B7) or a hair, skin and nail supplement, tell us first. The FDA warns that high-dose biotin can interfere with some lab tests, including hormone and thyroid tests.
Total includes all testosterone, bound and unbound. Free is only the unbound part that tissues can use directly.
It’s estimated from total testosterone, SHBG and albumin, a standard and reliable approach.
Yes, especially when SHBG is high. That’s why we look at all three numbers together.
Have questions about your labs?
Book a hormone and wellness consultation at Serene Med Spa in Barboursville, WV. We’ll review your symptoms, order the right panel and walk you through every result.
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