Hormones are substances produced naturally in the body. They control many important functions, including how we grow and develop.
Hormones are produced by a number of different organs and glands, which together are known as the endocrine system.
Testosterone is a hormone that helps with many body functions.
It affects sex drive, helps keep bones and muscles strong, controls body fat, helps make red blood cells, and is important for making sperm.
However, testosterone also makes prostate cancer cells grow.

Hormone therapy is a treatment that reduces or blocks testosterone in the body. Since prostate cancer cells need testosterone to grow, this helps shrink the cancer and slow or stop its growth.
Hormone therapy can be injections or tablets. Another type is the surgical removal of the testosterone producing part of the testicles. In some cases, these treatments may be combined.
The type of hormone therapy you are offered will depend on:
- The stage of the cancer (its size and how far it has grown).
- The grade of the cancer (how abnormal the tumour cells are).
Examples of hormone therapy:
Hormone therapy can also be known as:
- Androgen deprivation therapy, or ADT.
- Androgen suppression therapy.
- Chemical castration.
- Surgical castration.
The animation below explains in more detail exactly how hormone therapy works.
Other useful resources
- Hormone therapy (injections)
Information from The Infopool.