Testosterone is the male sex hormone. As men get older, their bodies produce less of it. Starting in middle age, it often drops below levels that doctors consider normal.
Low testosterone -- also known as hypogonadism or low T -- can affect your overall health. But some doctors say it’s just a normal, harmless part of aging.
Testosterone helps bring on the physical changes that turn a boy into a man. This time of life is called puberty. Changes include:
- Growth of the penis and testes
- Growth of facial, pubic, and body hair
- Deepening of the voice
- Building muscles and strong bones
- Getting taller
Men also need normal amounts of this hormone to make sperm and be able to have children.