Shutterstock.com
A trial to assess the benefits and risks of puberty-suppressing hormone treatment in children and young people who question their gender has been commissioned by NHS England.
The ‘Pathways trial’, announced on 22 November 2025, will be led by researchers at King’s College London and will involve 226 children and young people aged under 16 years with a diagnosis of gender incongruence, who have reached puberty and are accessing gender services.
The trial, expected to begin in January 2026, will assess the impact of gonadotropin-releasing hormone (GnRH) analogues for puberty suppression on outcomes such as quality of life, mental health, gender and body distress, and physical health.
Participants must meet inclusion criteria, including having a strong desire to be a different gender from their birth-assigned sex, and gender incongruence that has persisted for a minimum of two years.
They will be randomised into two groups; one group will start treatment straight away while the other will start after 12 months. Participants will be regularly followed up in the trial for two years after their baseline assessment. During this time, they will complete research procedures every three months.
After the first two years, all participants will be included in annual follow-up throughout the study period.
Following a temporary emergency ban, puberty-suppressing hormones were banned indefinitely in the UK in December 2024 for patients aged under 18 years, owing to a lack of evidence on their effects in this age group.
The Cass review of gender identity services, published in April 2024, echoed these findings.
As a result of the ban, children and young people can only be prescribed the drugs as part of a trial.
Commenting on the study, Hilary Cass, paediatrician and chair of the Cass review, said: “My review uncovered a very weak evidence base for benefits from the use of puberty blockers for children and young people with gender dysphoria. In fact, some children had more negative than positive effects.
“However, given that there are clinicians, children and families who believe passionately in the beneficial effects, a trial was the only way forward to make sense of this.”
Fiona McIntyre, policy and practice lead at the Royal Pharmaceutical Society (RPS), said: “This new study will not immediately affect pharmacists on the ground — though like other healthcare professionals, young people and their families may seek information from their pharmacist when they see information about the clinical trial in the media.
“In the meantime, legislative changes brought about by The Medicines (Gonadotrophin-Releasing Hormone Analogues) (Emergency Prohibition) (England, Wales and Scotland) Order 2024 provide pharmacists with a clear legislative framework for the supply of puberty blockers on prescription.”
In August 2024, the RPS warned that pharmacists were at risk of being criminalised over the supply of puberty blockers, in response to the emergency ban.
The Pathways trial is part of a wider Pathways project, which will follow children and young people who are attending NHS children and young people’s gender services and will include those prescribed puberty blockers and those who are not.
