Testosterone is an important hormone. It helps men develop during puberty, and as they age, it plays a critical role in helping control fat levels, cholesterol, and glucose levels. Testosterone ...

It's natural for testosterone to fluctuate, but sleep, diet and other factors can affect a man's levels on a daily basis.

What are normal testosterone levels by age? An older photographer mentors a younger one. Testosterone is an important hormone. It helps men develop during puberty, and as they age, it plays a critical ...