Did you know Testosterone levels decrease in men starting in their twenties? Hormonal balance is the key to male vitality. Total testosterone levels are highest in the early twenties and then start to decline at the rate of approximately 1% per year.(*) This drop-in total testosterone is gradual and the effects are not necessarily noticed for some time. What appears to be more relevant is the drop in free testosterone; this is the active form of testosterone that is not bound in the blood to the protein, sex hormone-binding globulin (SHBG). This protein limits the amount of free (active) testosterone by hooking up to it, making it unavailable to tissue. As men get older, the mechanisms for freeing enough testosterone begin to shut down.