Hormone therapy for prostate cancer 2: The role of hormones

Hormones are substances made naturally in your body. They act as chemical messengers and influence the growth and activity of your cells.

All your hormones are produced by different organs and glands, which together are known as the endocrine system. For example, the testicles produce the hormone testosterone.

Most of the testosterone in your body is made by the testicles. A small amount also comes from your 2 adrenal glands, which sit above each of your 2 kidneys.

During puberty, testosterone helps to develop body and facial hair, a deeper voice and muscle strength. Testosterone is also needed to make sperm.

Testosterone levels generally decrease with age, so older people tend to have lower testosterone levels.

Testosterone affects your overall health throughout your life and is important for: puberty and sexual development, sexual desire, erections, the size and function of the penis, and the production of sperm, controlling the strength of your bones and muscles as well as the way fat is distributed in your body. It also controls how the prostate grows and develops.