Puberty blockers

Puberty blockers, also called puberty inhibitors, are drugs used to postpone and temporarily suspend puberty in children and teenagers. These drugs are called gonadotropin-releasing hormone (GnRH) agonists, and they inhibit the action of testosterone. Delaying or temporarily suspending puberty is a medical treatment for children whose puberty started abnormally early (precocious puberty). The drugs are also commonly used for children with idiopathic short stature, for whom these drugs can be used to promote development of long bones and increase adult height. Additionally, they are used for transgender children, including those who identify as nonbinary, to stop the development of features that they consider to mark the wrong sex, with the intent to provide transgender youth more time to explore their identity.

In adults, the same drugs are used to treat endometriosis (a menstrual disorder), prostate cancer, and other conditions.

Medical uses
Puberty blockers prevent the development of biological secondary sex characteristics. They slow the growth of sexual organs and production of hormones. Other effects include the suppression of male features of facial hair, deep voices, and Adam's apples for children and adolescents, and the halting of female features of breast development and menstruation.

Transgender youth are a specific target population of puberty blockers to halt the development of natal secondary sex characteristics. Puberty blockers allow patients more time to solidify their gender identity, without developing secondary sex characteristics. If a child later decides not to transition to another gender, the effects of puberty blockers can be fully reversed by stopping the medication. Puberty blockers give a future transgender individual a smoother transition into their desired gender identity as an adult.

While few studies have examined the effects of puberty blockers for gender non-conforming or transgender adolescents, the studies that have been conducted indicate that these treatments are reasonably safe, and can improve psychological well-being in these individuals. In 2019, a study in the journal Pediatrics found that access to pubertal suppression during adolescence was associated with a lower odds of lifetime suicidality among transgender people.

The potential risks of pubertal suppression in gender dysphoric youth treated with GnRH agonists may include adverse effects on bone mineralization.

Research on the long term effects on brain development is limited, but a 2015 study published in the journal Psychoneuroendocrinology observed the executive functioning in 20 transgender youth treated with puberty blockers compared to untreated youth with gender dysphoria and found that there was no difference in performance.

Administration
The medication that is used in order to stop puberty comes in two forms: injections or an implant.

The injections are leuprorelin made intramuscularly by a health professional. The patient may need it monthly (Lupron Depot, Lupron Depot-PED) or each 3, 4 or 6 months (Lupron Depot-3 month, Lupron Depot-PED-3 month, Lupron Depot-4 month, Lupron Depot-6 Month).

The implant is a small tube containing histrelin. The implant needs to be replaced every year, and is implanted subcutaneously in the upper arm. The doctor makes a small cut in the anesthetized skin of the patient and then inserts the implant. The patient must be careful after the operation to keep the cut clean, dry, and to not move the bandage and the surgical strips or stitches used to close the incision on the skin. The drug is then gradually released in the body during 12 months and it has to be replaced by another one later to continue the treatment. The total cost of histrelin treatment with the surgery is $15,000.

The combination of bicalutamide, an antiandrogen, and anastrozole, an aromatase inhibitor, can be used to suppress male puberty as an alternative to GnRH analogues, or in the case of gonadotropin-independent precocious puberty, such as in familial male-limited precocious puberty (also known as testotoxicosis) in children who were assigned male at birth, where GnRH analogues are ineffective.

Puberty blockers for transgender youth
For all young people, puberty develops in a sequence of five Tanner Stages. These stages do not happen at the same ages for everyone, so some children go through stages years earlier or later than their peers. Before puberty, children are in Tanner Stage One. The earliest that a transgender child is eligible to take puberty blockers is during Tanner Stage Two, which is a span of a few months when the first signs of puberty appear.