What is the primary role of testosterone in males?

The primary role of testosterone in males is to bring about male characteristics. Testosterone is the principal male sex hormone and is crucial for the development of physical traits associated with masculinity. This includes the promotion of muscle mass, the deepening of the voice, the growth of facial and body hair, and the development of the male reproductive system. During puberty, the increase in testosterone levels stimulates these changes, contributing to the overall physical transformation of boys into adult males.

While testosterone does have other roles in the body, such as influencing libido and playing a part in bone density and fat distribution, its defining function is to drive the development of male secondary sexual characteristics. This makes it a vital hormone for male health and reproduction.