Puberty blockers are prescribed for young transgender people who wish to prevent physical development during puberty. In this article, we discuss puberty blockers and their side effects. We also discuss the pros and cons of these hormone blockers.

They can come in a variety of forms including:

  • Nasal Spray
  • Injection
  • Implant


Pubertal development can be very distressing in someone who identifies as a different gender to the sex they were assigned at birth.

Puberty blockers can alleviate this distress by suppressing the production of sex hormones (oestrogen or testosterone) and delaying the changes of puberty.

Some people have claimed that puberty blockers are an experimental or unsafe treatment or that puberty blockers’ side effects are severe, but this is not the case.

The efficacy of puberty blockers in adolescents with gender dysphoria is adequately evidenced and no more experimental than in other areas of paediatric medical care.

GnRH analogues – the medical name for puberty blockers – or just ‘blockers’ – have been used to manage precocious puberty in children for many years and to prevent pubertal development in transgender children for many years.

Puberty blockers are not necessary for pre-pubertal children. Many young children are naturally inclined to explore their gender identity, which does not require medical intervention.

Blockers are not prescribed to anyone unless:

  1. They have a history of discomfort with their assigned sex at birth.
  2. They wish to prevent pubertal developments that do not align with their gender identity.
  3. These feelings are worsened by the onset of puberty.

When blockers are clinically indicated, it is only when the individual has moved to Tanner stage two, the beginning of the physical developments caused by the onset of puberty, that treatment is needed.


Puberty Blockers History

Puberty blockers have been used for this reason for over two decades.

Initial guidelines for the use of puberty blockers in adolescents were developed in the mid-1990s and since then have been introduced into international guidance by the World Professional Association for Transgender Health and the Endocrine Society.


Puberty Blockers in Transgender Care

In transgender care, most of the medications used to treat gender dysphoria are not licensed for this specific indication, although doctors will be familiar with their use for other purposes.

Unlicensed medicine refers to medication that is prescribed for use other than that listed in terms of its licence within the country of use and is commonplace in many areas of medical care.

Unlicensed, off-licence and off-label refer only to the use of the medication beyond its licence and do not refer to improper, illegal, unsafe or experimental use.

Read more about ‘off-label’ medication use here.


Effects of Puberty Blockers on Those Assigned Male at Birth

Below is a list of effects and side-effects of puberty blockers on those who are assigned male at birth:

Affected Area
Growth of Facial or Body Hair Stop or Limit
Deepening of the Voice Prevent
Broadening of the Shoulders Prevent or Limit Further Broadening
Adam’s Apple Growth Reduction or Complete Prevention
Gonads and Erectile Tissue Stop or Prevent


Effects of Puberty Blockers on Those Assigned Female at Birth

The effects and side-effects of puberty blockers are different for those assigned female at birth:

Affected Area
Breast Tissue Development Stop or Limit
Hip Broadening Prevent or Limit Broadening
Monthly Bleeding Stop


Puberty Blockers: Side Effects

Some people are concerned about the side effects of puberty blockers. The main areas of concern most widely referenced are that blockers impact bone density and fertility and promote a potential increased chance of further medical transition.


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Limited studies have suggested that where bone density is impacted in young people using blockers, it is due to the absence of hormones rather than the result of the blockers, as hormones are essential for bone health.

This supports the argument for the timely use of gender-affirming hormones in trans youth and not allowing prolonged periods without sex hormones. This is an active area of research. You can read more about bone density here.

While sex hormones are suppressed with the use of blockers, sperm and eggs will not be produced. However, if a patient later wants to have biological children or preserve genetic material, the blockers can be stopped, and production can be allowed to resume.

Much research is ongoing into retrieving gametes (sperm and eggs) directly from the ovaries and testicles. Read more about the latest research into fertility options for transgender people.

Puberty blockers do not make children transgender, nor do they substantially increase the likelihood of further medical transition.

Individuals who are using puberty blockers as part of gender-affirming care may indeed go on to use gender-affirming hormones, but this is a continuation of management for gender incongruence rather than a consequence of blockers.

Because the ‘diagnosis’ was correct, the person was indeed trans, and they desired the hormones and physical developments that aligned with their gender rather than those that their body would naturally produce.

Furthermore, the use of puberty blockers in early adolescence reduces the likelihood of future invasive treatments in patients who do go on to medically transition.

For instance, trans men who used puberty blockers in adolescence are less likely to need a mastectomy (top surgery), and trans women who used puberty blockers in youth are less likely to pursue facial feminisation surgery.


Ask about Puberty Blockers here


Further Reading:

A flawed agenda for trans youth – Lancet

Pubertal Suppression for Transgender Youth and Risk of Suicidal Ideation

Full article: Is puberty delaying treatment ‘experimental treatment’?

Standards of Care – WPATH

Transgender Health: An Endocrine Society Position Statement