Skip to content

Coronavirus antibody and PCR tests available. Shop now

Free Testosterone - Calc.


Most testosterone circulating in the blood is bound to proteins, in particular SHBG and albumin; only 2-3 % of testosterone is free and available to cells. This test uses an algorithm to calculate the level of free or unbound testosterone in relation to total testosterone, SHBG and albumin.

What might a low result mean?

Even if you have normal total testosterone levels you might have low free testosterone levels, especially if you have elevated SHBG. Low free testosterone can lead to symptoms which can include of lack of libido, difficulty gaining muscle, and low mood.

What might a high result mean?

Elevated free testosterone is normally the result of having high levels of total testosterone. High testosterone is not common in men and is normally caused by taking supplements aimed at increasing testosterone levels e.g. testosterone replacement therapy or steroids. Having high testosterone levels can impact the production of other hormones and can also cause your body to stop producing its own testosterone. Long term, it carries other health risks like high cholesterol and blood clots which raise your risk of heart disease and strokes.

In women, high free testosterone can be seen with polycystic ovaries, a condition in which a woman produces high levels of male hormones which can cause irregular periods as well as some male physical characteristics.