What do puberty blockers do?

Puberty blockers are drugs designed to halt the onset of puberty in children/young people. The patient would be administered with a hormone blocker that slows the release of and suppresses the hormones oestrogen and testosterone which are produced in larger quantities during puberty, hence the name puberty blockers. These hormones cause changes in the body like the development of breasts, periods, facial hair or a deeper voice. By preventing or delaying these changes, a trans person can avoid the procedures and surgeries required to reverse these changes later on.

Puberty blockers can be taken by adults, but this will largely only affect psychological changes rather than physical, and this is often used before a trans person is able to gain access to cross-sex hormones.