U.K. trial to test puberty blockers on 11-year-olds

A United Kingdom health agency will begin recruiting children as young as 11 years old for a puberty blocker trial. The trials will assess how puberty-blocking drugs affect the physical, mental, and social well-being of children and teenagers, the Medicines and Healthcare products Regulatory Agency said Friday. The drugs will be used to delay puberty. The trials, run by King’s College London, were previously paused in February due to safety concerns for the children’s health. The trials have been restarted under updated guidance, with more than 200 children set to be recruited for it starting in August.

Multiple advocacy groups previously took legal action against the trials, questioning their usefulness. The legal action is still ongoing. The United Kingdom indefinitely banned the use of puberty blockers on minors outside of research settings in 2024.

What criteria must children meet to participate in the trials?

• Girls must be at least 11 years old and boys at least 12 years old to participate in the study.

• The revised guidelines also say treatment should be stopped if vaginal bleeding occurs, or bone health or mental cognition worsens. Researchers have also outlined more information to preserve children’s fertility.

• Children must demonstrate they understand the possible risks of the trials and have parental consent to participate.

Dig deeper: Read Christina Grube’s report on when England’s National Health Service first commissioned the study.