en English

Puberty blockers are recommended for children and adolescents with gender dysphoria, but some have criticised them as an experimental treatment. Here we look at the medical evidence for puberty blockers.

One of the most frequently cited objections to the use of puberty blockers is a lack of research into their use and the potential long-term consequences.

In reality, there are over two decades of clinical practice supporting the use of puberty blockers in young people with gender dysphoria, with guidelines first being drafted in the mid-1990s, and the use of these GnRH analogues (puberty blockers) to safely manage precocious puberty goes back even further.

Longitudinal research into puberty blockers is difficult to carry out. Good quality research revolves around good quality studies or trials. Long-term medical studies are randomised-controlled and double-blind.

According to the definition outlined by the National institute for Health and Care Excellence (NICE), a randomised controlled trial is a study in which a number of similar people are randomly assigned to two (or more) groups to test a specific drug, treatment or other intervention.

One group (the experimental group) has the intervention being tested, the other (the comparison or control group) has an alternative intervention, a dummy intervention (placebo) or no intervention at all. The groups are followed up, in this case to be effective that would need to be for the rest of their lives, to see the real-life impact of the intervention. Outcomes are measured at specific times and any difference in response between the groups is assessed statistically. This method is also used to reduce bias.

NICE defines a double-blind study (also known as blinding or masking) as a way to prevent researchers, doctors and patients in a clinical trial from knowing which study group each patient is in so they cannot influence the results. This is achieved by randomly sorting the patients into study groups with neither the patients nor the researchers/doctors knowing which group the patients are in.

So let’s look at how that might work if we were to apply this to trails around the effectiveness of puberty blocking medication.

In order to carry out effective trials, participants – in this case, young people with gender dysphoria – would be divided into two equal groups. One group would be given puberty blockers, and the other wouldn’t, and nobody – not even the researchers – would know which group was which.

While this is a proven model for medical research in general, there are several immediate flaws that present when applying it to puberty blockers.

First, puberty blockers are typically used for the immediate treatment of gender dysphoria and longer-term harm reduction. It would be unethical to be faced with 100 teenagers who were asking for blockers, and carry out a trial in which only half of them were accessing the care they needed, with the other half getting no treatment at all. This would require us to deny a group of young people who were clearly suffering, access to a medication which is known to improve health outcomes for the sake of further research.

Secondly, because puberty blockers suppress the physiological changes of puberty, in any longitudinal study it would quickly become apparent which group was the control group when the changes brought about by puberty began to manifest. This would prevent the test from being double blind, thereby invalidating any data that might come from it. As such we must rely on observational research, of which there is plenty. Best practice in this instance, and the only real ethical option available, is to give the treatment we know appears to be safe and effective, and monitor what happens over time.

Even though there may be some medical treatments that are experimental, that does not mean they are not needed, or indicated in that person’s care. Just because it is experimental, does not mean it should be denied.


We support trans youth – find out more


Of course, that’s not to say that there hasn’t been any research into the use of puberty blockers. Research into the effects of GnRH analogues on children with precocious puberty can inform our understanding of the long-term effects of blockers, like this study which demonstrated that blockers have minimal lasting effects on fertility. It has also been possible to carry out some longitudinal research on the effects of blockers by studying transgender adults, and comparing those who received blockers during adolescence to those who did not. These studies have largely shown that blockers have a positive effect on adult wellbeing, particularly in terms of mental health outcomes. And while there continue to be active research areas for the use of puberty blockers, such as bone density, all medical evidence suggests that the benefits of puberty blockers outweigh the risks.

As such, with decades of clinical practice supporting their use and ongoing research into the outcomes of treatment, blockers are no more experimental than any other pediatric treatment.

Even if the treatment was experimental, the observational and anecdotal results alone are sufficient to indicate good clinical practice. Use of blockers directly correlates to improved quality of life for trans young people, and significantly reduces suffering as a result of unwanted pubertal changes.

All the information we have about puberty blockers suggests that the treatment is safe, effective, and has positive outcomes for young people of all genders. If further research areas have been identified, it is important to pursue them as much as is practical – but not at the cost of young people’s wellbeing. Even relatively conservative medical opinions are clear that, while there are areas for further research to be conducted, the benefits of puberty blockers and gender-affirming care are evident.

To help you stay aware of the facts, we’ve put together a list of myths about puberty blockers, along with the medical evidence that disproves them. If you’re a parent, child, or family member concerned about blockers, Mermaids also have resources for education and support. We can get trans young people the support they deserve, as long as we listen to them and keep ourselves informed of the facts.


Photo by Sharon McCutcheon from Pexels