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 ...

New U.S. dietary guidelines for the first time include advice for men on maintaining healthy testosterone levels.

It checks the level of testosterone in your blood. Your doctor uses it to diagnose conditions caused by too much or too little testosterone. That’s a hormone produced in a man’s testes. Women make ...