In brief
Measures testosterone, the main male sex hormone, which females also have in smaller amounts.
What it measures
Total testosterone, which includes testosterone bound to proteins such as SHBG and albumin, and sometimes free testosterone, which is not bound.
Why it is done
In men, to investigate infertility, low sex drive or erectile problems. In women, to investigate irregular or absent periods.
Reading the results
- Testosterone levels vary widely, and a result flagged as high or low does not necessarily mean anything is wrong.
- Testosterone is responsible for sexual function, bone health and muscle mass.
Before the test
None, but testosterone is highest in the morning and falls during the day, so timing matters.
What can affect the result
- Time of day
- Age
- Some medicines, including steroids
- Alcoholism and liver disease in men
Related topics
Sources
Test information summarised from the sources listed on this page, read on 19 October 2026. General education only, not medical advice. Spotted a mistake? Please tell us through the HuBu-Intel contact page.