Free Testosterone

What is free testosterone and why does it matter for human performance?

Free testosterone refers to the portion of testosterone in the bloodstream that is not bound to carrier proteins, such as sex hormone-binding globulin (SHBG), and is therefore available for use. In contrast, total testosterone encompasses both free and bound testosterone, providing a comprehensive measure of the hormone's presence in the blood. The distinction between these two forms is crucial because only free testosterone is bioavailable and can exert its effects on the body. This includes aiding in muscle development, enhancing strength, and boosting the body's oxygen-utilizing capacity during exercise. For men, maintaining adequate levels of free testosterone is essential for bone health and preventing age-related bone loss.