Total testosterone measures the full amount of the hormone in your blood, while free testosterone represents the small, active portion your body can actually use to support muscle growth, energy, mood ...

This article was reviewed by Felix Gussone, MD. If you’ve been feeling a bit more couch potato than go-getter lately, dragging through the day, snapping at people for no reason, or wondering where ...

What Is Low Testosterone (Testosterone Deficiency)? Testosterone is the primary androgen — or male hormone — in your body. Low testosterone affects up to 39 percent of adult men in the US over the age ...