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Puberty blockers (also called puberty inhibitors or hormone blockers) are medicines used to postpone puberty in children. The most commonly used puberty blockers are gonadotropin-releasing hormone (GnRH) agonists, which suppress the biosynthesis of , such as (e.g. testosterone) and (e.g. estradiol). Puberty blockers are used to delay puberty in children with precocious puberty. Since the 1990s, they have also been 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 (WPATH). 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.
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.
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.
A 2014 longitudinal study followed 55 young transgender adults (22 trans women and 33 trans men) 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.
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 (including positive results relating to body image, gender dysphoria, depression, anxiety, suicide risk, quality of life, and cognitive function) 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.
A number of different drugs are used as puberty blockers:
Outside of the United States, companies such as Ferring Pharmaceuticals, Ipsen, Takeda Pharmaceutical Company, Astellas Pharma, Sandoz, and Sun Pharmaceutical Industries supply much of the rest of the world with the various puberty blockers. Ferring Pharmaceuticals, based out of Switzerland, generate two separate products of triptorelin (Decapeptyl and Gonapeptyl). Originating in France, Ipsen also produces triptorelin (Decapeptyl). German/Swiss company Sandoz makes leuprorelin (Leuprorelin Acetate, Lucrin, Eligard). In Japan, Takeda Pharmaceutical Company and Astellas Pharma create leuprorelin (Lupron Depot) and goserelin (Zoladex). Indian company Sun Pharmaceutical Industries mainly produces leuprolide acetate generic injectables. AbbVie is also a player internationally.
Common short-term side effects may include injection site reactions, headaches, mood swings, changes in weight or appetite, fatigue, insomnia, muscle aches and changes in breast tissue, but these are usually manageable. Bone mineral density is reduced during treatment, though there is no evidence of long-term effects (see also § Bone health in § Long-term). To protect against this, doctors recommend exercise, calcium, and Vitamin D. The American Academy of Pediatrics (AAP) also notes delaying puberty beyond peers may be stressful.
In 2016, the FDA ordered drugmakers to add warning labels that state: "Psychiatric events have been reported in patients", including symptoms "such as crying, irritability, impatience, anger and aggression."
In 2022, the FDA reported that there have been six cases of idiopathic intracranial hypertension in 5 to 12-year-old children assigned female at birth taking puberty blockers. Five were receiving treatment for precocious puberty and one was transgender and receiving treatment for gender dysphoria. Morissa Ladinsky, a University of Alabama-Birmingham pediatrician who works with transgender youth, said that it "is an inordinately well-known side effect that can happen for many, many different medications, most commonly, oral birth control pills." Referring to the six reported cases, Ladinsky said that "It doesn't even approach any semblance of what we call in medicine, statistical significance".
The Endocrine Society Guidelines, while endorsing the use of puberty blockers for treatment of gender dysphoria, underscores the need for more rigorous safety and effectiveness evaluations and careful assessment of "the effects of prolonged delay of puberty in adolescents on bone health, gonadal function, and the brain (including effects on cognitive, emotional, social, and sexual development)."
The longest follow-up study followed a transgender man who began taking puberty blockers at age 13 in 1998, before later taking hormone treatments and getting gender confirmation surgery as an adult. His health was monitored for 22 years and at age 35 in 2010 was well-functioning, in good physical health with normal metabolic, endocrine, and bone mineral density levels. There were no clinical signs of a negative impact on brain development from taking puberty blockers.
According to a 2020 study, genital tissue in transgender women may not be optimal for potential vaginoplasty later in life due to underdevelopment of the penis when using penile inversion vaginoplasty. Several other methods such as bowel vaginoplasty, which uses part of the sigmoid colon to form the canal instead, or a peritoneal pull-through vaginoplasty which harvests a skin graft from the peritoneum are not affected by this as they do not require the penile tissue to form the vaginal canal.
An independent review into gender-affirming care for minors commissioned by the New South Wales government and released in September 2024 found that puberty blockers are "safe, effective and reversible", while acknowledging that the evidence for this and other interventions "remains weak due to poor study designs, low participant numbers and single-centre recruitment", calling for more long-term research.
This requires a formal diagnosis of gender incongruence (ICD-11 HA60) from a medical professional, and the adolescent must have reached at least Tanner stage 2 of pubertal development.
The use of puberty blockers in youth experiencing gender dysphoria has been endorsed by the following organizations:
A qualitative study investigating the experience of trans youth in seeking and receiving gender-affirming care at Canadian specialty clinics shows a mix of positive and negative outcomes. People reported improvements in their well-being, frustrations with treatment protocols and wait lists, and concerns with their transition journey.
According to the Canadian Pediatric Society in 2024, "Current evidence shows puberty blockers to be safe when used appropriately, and they remain an option to be considered within a wider view of the patient's mental and psychosocial health."
In 2022, France's Académie Nationale de Médecine urged caution when considering puberty blockers due to potential side effects, including "impact on growth, bone weakening, and risk of infertility". This change to the guidelines has not changed actual practice.
In late 2024, the French Society of Pediatric Endocrinology and Diabetology released the country's first ever guidelines for medical care of trans youth, in which they recommended patients who have hit at least Tanner stage 2 to receive puberty blockers along with calcium and vitamin D supplements.
The use of puberty blockers has been endorsed by numerous medical organizations:
Additionally, the use of puberty blockers in transgender youth is supported by:
In November 2024, the Ministry of Health released an evidence brief on puberty blockers. The brief found there to be a lack of evidence for both the efficacy and harms of puberty blockers and recommended "a more precautionary approach". The country did not ban puberty blockers and one doctor who provides the treatments in New Zealand said it "would not change the way in which he practiced". In April 2025, potential further restrictions on access to puberty blockers proposed by the ministry were met with backlash by a number of New Zealand medical bodies.
In 2023, the Norwegian Healthcare Investigation Board, an independent non-governmental organization, issued a non-binding report finding "there is insufficient evidence for the use of puberty blockers and cross sex hormone treatments in young people" and recommending changing to a cautious approach. The Norwegian Healthcare Investigation Board is not responsible for setting healthcare policy, and the Directorate, which is, has not implemented the recommendations, though they have said they are considering them. Misinformation that Norway had banned gender affirming care proliferated on social media.
However, other providers in Sweden continue to provide puberty blockers, and a clinician's professional judgment determines what treatments are recommended or not recommended. Youth are able to access gender-affirming care when doctors deem it medically necessary. The treatment is not banned in Sweden and is offered as part of its national healthcare service.
Previously, on 30 June 2020, the NHS changed its website, replacing the statement that puberty blockers were "fully reversible" and that "treatment can usually be stopped at any time"; with "little is known about the long-term side effects of hormone or puberty blockers in children with gender dysphoria.
A 2020 commissioned review published by the UK's National Institute for Health and Care Excellence (NICE) concluded that the quality of evidence for puberty blocker outcomes (for mental health, quality of life and impact on gender dysphoria) was of very low certainty based on a modified GRADE approach, but that it was plausible that the outcomes would have been worse without treatment. A subsequent systematic review re-affirmed the conclusions of the NICE report, concluding that the currently available studies have "significant conceptual and methodological flaws". A 2024 review of evidence on behalf of the Cass Review came to a similar conclusion.
The NICE review has been criticized by organizations that support the use of puberty blockers such as WPATH and EPATH, and in a WPATH International Journal of Transgender Health article by Cal Horton for excluding studies combining puberty blockers and hormone therapy, and also by parents of transgender youth for excluding evidence of its safety when used, albeit at a much younger age, by cisgender youth being treated for precocious puberty. Horton criticised the review for prioritizing high-quality evidence according to the GRADE approach, which designates randomized control trials (RCTs) as "high quality", since RCTs are widely considered infeasible and unethical for transgender youth if those in the control group are denied medical treatment. Horton also argued that it had not followed GRADE guidance which states that "low or very low quality evidence can lead to a strong recommendation" by not taking the low-quality studies into account when forming evidence review recommendations.
The Bell v Tavistock decision by the High Court of Justice for England and Wales ruled children under 16 were not competent to give informed consent to puberty blockers, but this was overturned by the Court of Appeal in September 2021.
In 2022, the British Medical Association opposed restrictions on puberty blockers, and the NHS restricted their use for children under 16 years of age to centrally administered clinical research.
The April 2024, Cass Review stated that there was inadequate evidence to justify the widespread use of puberty blockers for gender dysphoria, and that more research was needed to provide evidence as to the effectiveness of this treatment, in terms of reducing distress and improving psychological functioning. This led to a de facto moratorium of the routine provision of puberty blockers for gender dysphoria within NHS England and NHS Scotland outside of clinical trials, and a subsequent ban on private prescription of puberty blockers in the United Kingdom.
Children already receiving puberty blockers via NHS England will be able to continue their treatment. In England, a clinical trial into puberty blockers is planned for early 2025.
In July 2024, the Royal College of General Practitioners stated that for patients under 18, no general practitioner should prescribe puberty blockers outside of a clinical trial, and the prescription of gender-affirming hormones should be left to specialists. They affirmed they will fully implement the Cass Review recommendations.
In December 2024, the Northern Ireland Executive announced a permanent ban on puberty blockers for under-18s, with the Executive's Deputy First Minister, Emma Little-Pengelly, saying it was "the right approach, informed by medical and scientific advice. The protection and safety of our young people must be paramount." The following day, the Health Secretary, Wes Streeting, announced in the House of Commons that the previously enacted ban on puberty blockers in England would be made indefinite and would be reviewed in 2027.
For years, the FDA, Endocrine Society, American Academy of Pediatrics (AAP) and many other pediatric associations have supported the use of Gonadotropin-releasing hormone analogs (GnRHas) in central precocious puberty (CPP). Access to treatment depends on the classification of precocious puberty as well as other guidelines implemented by the Endocrine Society. To determine if a patient is experiencing precocious puberty and should receive treatment, a physical exam, blood test, and x-rays are required.
In 2009, the Lawson Wilkins Pediatric Endocrine Society and European Society for Pediatric Endocrinology published a consensus statement highlighting the effectiveness of Gonadotropin-releasing hormone analogs(GnRHas) in early onset central precocious puberty. They confirmed that the use of Gonadotropin-releasing hormone analogs (GnRHas) has had a positive effect on increasing adult height. However these Endocrine Societies believe additional research should be conducted before routinely suggesting GnRHAs for other conditions. There is still some uncertainty surrounding the effectiveness of GnRHas when utilized for other conditions.
Currently under FDA regulation, the use of puberty blockers in pediatrics with gender dysphoria is considered off-label.
The use of puberty blockers in youth experiencing gender dysphoria has been supported by the following organizations:
There has been an increase in youth requesting treatment for gender affirming medical care. The increased medical coverage and societal awareness of transgender youth may be shifting accessibility to care.
In April 2021, Arkansas passed a ban on treatment of minors under 18 with puberty blockers, but it was temporarily blocked by a federal judge a week before the law was set to take effect. In April 2022, Alabama passed a ban from minors under 19 from obtaining puberty blockers and made it a felony for a doctor to prescribe puberty blockers to a minor with a punishment of up to ten years in prison. The Alabama law was partially blocked by a federal judge a few days after the law took effect. In August 2022, Florida banned Medicaid from covering gender affirming care, including puberty blockers.Medical experts criticized the report for citing pseudo-scientific sources and repeatedly dismissing legitimate medical studies as "low quality", which they said showed a flawed understanding of statistics, medical regulation, and scientific research.
As of July 2024, 26 states have enacted some form of ban on gender-affirming care for minors, but not all of these ban puberty blockers. Currently, only 18 of the 26 states have complete bans which are fully in effect. Six states have only partial bans and two are currently blocked from taking effect. While some states have banned all forms of medical transition, others have banned only specific types such as surgery. Six states have exceptions which allow minors who were already receiving gender affirming care prior to the ban to continue their treatments. Currently, all 26 states make exceptions for puberty blockers, hormones and surgery for cisgender and intersex children. Only one state, West Virginia, makes exceptions in cases of "severe dysphoria". There is also currently only one state, Missouri, that has a ban which is set to expire after a certain period of time. Nearly all states with restrictions include specific provisions with penalties for providers and 4 states include provisions directed at parents or guardians. An additional 4 states include laws/policies that impact school officials such as teachers and counselors, among others.
In response to these bans, many Democrat-controlled states have gone in the opposite direction and enacted laws protecting access to gender affirming care for minors and adults. These laws, often called "shield" laws, often explicitly combine protections for gender-affirming care and abortion and cover a variety of protections including protecting both providers and patients from being punished, mandating insurance providers to cover the procedures and acting as "sanctuary states" that protect patients traveling to the state from other states that have banned such treatments among other things. As of June 2024, 16 states and the District of Columbia have enacted "shield" laws.
The UK's Cass Review was cited in the Indiana legislation to ban puberty blockers.
Some US state bans on gender affirming care including puberty blockers have been declared unconstitutional. Furthermore, bans on puberty blockers have been criticized as governments interfering with the patient-doctor relationship and taking away healthcare decisions from parents and families for their children. State level bans on gender affirming care, including puberty blockers, in the United States have led some families with transgender children to move out of their states.
In June 2025, the United States Supreme Court upheld a Tennessee law banning hormone treatments and puberty blockers for transgender minors. In United States v. Skrmetti, the Supreme Court ruled 6-3 that the law does not violate the equal protection clause of the 14th Amendment.
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