Puberty blocker
Puberty blockers are medicines used to postpone puberty in children. The most commonly used puberty blockers are gonadotropin-releasing hormone agonists, which suppress the natural production of sex hormones, such as androgens and estrogens. Puberty blockers are used to delay puberty in children with precocious puberty. They are also used to delay the development of unwanted secondary sex characteristics in transgender children, so as to allow transgender youth more time to explore their gender identity under what became known as the Dutch Protocol.
The use of puberty blockers is supported by the Endocrine Society and the World Professional Association for Transgender Health. In the United States, twelve major American medical associations, including the American Medical Association, the American Psychological Association, and the American Academy of Pediatrics support the use of puberty blockers. In Australia, four medical organizations support them.
In the 2020s, the provision of puberty blockers for gender dysphoria in children has become the subject of public controversy, with the United Kingdom stopping the routine prescription of puberty blockers and some states of the United States making their use a criminal offense. Several European health authorities have also issued more restrictive or cautious guidance on their use in minors, including Sweden's National Board of Health and Welfare recommending that puberty-suppressing and gender-affirming hormone treatments be provided in the context of research and only in exceptional cases, Finland's Council for Choices in Health Care stating that psychosocial support is first-line and that gender-affirming hormones are generally initiated no earlier than age 16, Denmark's Health Authority emphasising the risk of irreversible effects and limited evidence on long-term outcomes for medical treatment in those under 18, and Norway's Healthcare Investigation Board raising concerns about patient safety and the evidence base for treatment pathways.
Medical uses
Puberty blockers prevent the development of biological secondary sex characteristics. The same drugs are also used in fertility medicine and to treat some hormone-sensitive cancers in adults.Precocious puberty
Puberty blockers are commonly used to delay puberty in children with precocious puberty, a condition that activates the hypothalamic-pituitary-gonadal axis prematurely and initiates puberty at an inappropriate age. The main goal of treatment is to preserve children's adult height potential.Puberty blockers work by stabilizing puberty symptoms, decreasing growth velocity, and slowing skeletal maturation. The outcomes of treatment are assessed in terms of height, reproduction, metabolic, and psychosocial measures. The most pronounced effects on height have been seen in children experiencing the onset of puberty before 6 years of age; however there is variability in height outcomes across studies which can be attributed to varying study designs, time of symptom presentation, and time of treatment termination.
A study investigating the effects of puberty blockers on reproductive health showed no significant difference in the number of irregular menstrual cycles, pregnancies, or pregnancy outcomes between women who received treatment for precocious puberty and those who opted out of treatment. In terms of psychosocial markers, preadolescents and adolescents diagnosed with precocious puberty have shown body image concerns and demonstrated poor emotional regulation and high anxiety. Individuals with precocious puberty, early adrenarche, and early normal puberty show less stress after treatment compared to individuals without preexisting developmental conditions.
Overall, puberty blockers have demonstrated an excellent safety and efficacy profile for treating precocious puberty. The most common side effects reported include nonspecific headaches, hot flashes, and implant-related skin reactions.
Gender dysphoria
Puberty blockers are sometimes prescribed to young transgender people with gender dysphoria to temporarily halt the development of secondary sex characteristics. While there is evidence to suggest transgender youth may benefit from gender-affirming hormone therapy even at early puberty, there may be restrictions on prescribing HRT at younger ages. Puberty blockers are intended to allow patients more time to solidify their gender identity and give them a smoother transition into their desired gender identity as an adult. If a child later decides not to transition, the medication can be stopped and puberty will proceed.The "Dutch Protocol" is the first known example of the use of puberty blockers to treat gender dysphoria in children. It was developed by Peggy Cohen-Kettenis in the 1990s. The initial article describing the Dutch Protocol stated that the treatment was reversible and that a study of 54 children showed evidence that it had an overall positive outcome for those treated. A number of subsequent studies supported the treatment as safe and effective at delaying development of secondary sexual characteristics, and it became the standard treatment in the field.
Research
Studies examining the effects of puberty blockers for gender non-conforming and transgender adolescents have indicated that these treatments are reasonably safe, are reversible, and can improve psychological well-being in these individuals. Treatment of transgender adolescents with puberty blockers, especially when followed by gender-affirming hormone therapy, has been shown to reduce depression, anxiety, and suicidality. The World Professional Association for Transgender Health's Standards of Care 8, published in 2022, declared puberty-blocking medication to be medically necessary and recommends them for usage in transgender adolescents once the patient has reached Tanner stage 2 of development, because longitudinal data shows improved outcomes for transgender patients who receive them.A 2014 longitudinal study followed 55 young transgender adults over the entire duration of their puberty. Participants were assessed prior to puberty suppression around mean age 13-14, followed by another assessment at the beginning of gender-affirming hormones being introduced around mean age 16-17 and a post-adolescence review following a year or longer after gender-affirming surgery at a mean age of 20-21. The results of the longitudinal study found that gender dysphoria decreased and psychological health steadily improved and concluded that a multidisciplinary team of mental health professionals working together with physicians and surgeons and informed administration of puberty blockers, followed by cross-sex hormones and gender affirming surgery led to positive health outcomes, mental and physical for study participants.
A 2022 study published in the Journal of the American Medical Association found a 60% reduction in depression and 73% reduction in suicidality in transgender patients prescribed puberty blockers or gender affirming hormones.
In September 2024, the New South Wales government in Australia released an independent review into puberty blockers that they commissioned which found that the benefits of puberty blockers outweigh any possible risks. The review concluded that puberty blockers are "safe, effective and reversible".
A multi-year study published in September 2024 found that restrictions to transgender care, including restriction on access to gender-affirming puberty blockers, showed a direct link to negative mental health outcomes for transgender youth. The study followed the enactment of several laws in US states on restricting such access, which led to an increase of suicide attempts of 7-72% in transgender youth within one to two years following the enactment of laws restricting access.
A 2024 systematic review, which ranked studies it analyzed into quality buckets, found that synthesis of the available "moderate-quality and high-quality studies showed consistent evidence demonstrating efficacy for suppressing puberty." The review noted that there was limited, or inconsistent evidence in other regards, saying that they could not draw conclusions on the "impact on gender dysphoria, mental and psychosocial health or cognitive development." The review noted a current lack of high-quality research on puberty blockers in adolescence experiencing gender dysphoria and that "large well- designed research is needed" to better inform this area for the future.
In May 2025, a systematic review on the use of puberty blockers in adolescents was published in Frontiers in Endocrinology. It found that puberty blockers led to "significantly improved" mental health outcomes, "especially when GnRHa was followed by gender-affirming hormone therapy." The review said that "key clinical and ethical considerations—such as bone health monitoring, fertility counseling, psychological support, and informed decision-making—must guide treatment." The review recommends gender-affirming care such as puberty blockers for adolescents, along with professional mental health support. It also recommended further longitudinal studies to support safe and individualized care, noting the current lack of long-term data and a need for further study, highlighting areas of fertility preservation on skeletal health.