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 ...

A study published in the American Journal of Human Biology suggests that Western medical standards for male testosterone might not reflect the natural variation found in different environments.

Add Yahoo as a preferred source to see more of our stories on Google. Testosterone may be a key indicator of men's heart health and longevity, new research suggests.andreswd/Getty Images A study of 24 ...

Whenever one experiences growth hormones, peptide hormones, thyroid hormones, stress hormones or sex hormones, the body's chemical messengers play a key role in many essential bodily functions and ...