Testosterone **

Testosterone, a hormone found in both men and women, plays a crucial role in functions such as muscle growth, bone strength, and mood regulation. The Free Testosterone Index (FTI) specifically measures the amount of "free" testosterone available for its function, as opposed to the testosterone bound to proteins. This test is utilized by doctors to investigate symptoms such as fatigue, low sex drive, and muscular or skeletal issues, potentially caused by low testosterone levels.