Chemical castration reduces the testosterone levels of a male individual to those of a prepubescent boy and makes him impotent, reports Decca Aitkenhead for the Guardian. Other side effects include breast growth, hot flushes, heart problems and osteoporosis. These effects are achieved through the use of an anti-androgen drug such as leuprorelin.
As of 2015, chemical castration has also been used over the past 50 years for the beneficial effects it may have on the criminal tendencies of pedophiles and other criminals convicted of sexual offenses, according to Aitkenhead. The use of such a procedure, especially if it is performed as a punishment and not on a voluntary basis, raises complicated scientific and ethical questions, and it is not widespread. The effects of chemical castration on reducing sexual criminal behavior on such offenders is still not well-known, and more comprehensive studies need to be conducted.
The use of voluntary chemical castration in Scandinavia has reportedly reduced the recidivism of those convicted of sexual offenses against children from 40 percent to between 5 percent and 0 percent, states Aitkenhead. However, researchers admit trial studies are difficult to conduct partly because the effects of anti-androgens are so obvious it is difficult to properly use a control placebo group. Other drugs given to such offenders in treatment, such as antidepressants, may also account for some of the reduction in recidivism.