Puberty Blockers

Puberty blockers are medications (GnRH analogues such as triptorelin or leuprorelin) that suppress the hormonal regulation of puberty. In gender care, they are given to children who meet the diagnostic criteria for gender dysphoria when puberty begins. The long-standing portrayal of them as a harmless ‘pause button’ has been rendered outdated by recent international evaluations. Why this portrayal is inaccurate is explained in detail at puberteitsblokkers.nl.

Subtopics can be found under GnRH agonists in gender care.

Not a ‘reversible pause’

The claim that puberty blockers are ‘fully reversible’ and simply ‘buy time’ is no longer supported by the available evidence. Three observations are crucial:

• ~98% proceed to cross-sex hormones: both in the original Dutch cohort and in the British Tavistock data, virtually everyone who started blockers went on to take irreversible hormones. Rather than providing an open-ended delay, the treatment functions in practice as a stepping stone towards lifelong medicalisation.
• Impact on puberty itself: puberty is not merely a hormonal switch but a developmental period during which the body, brain and sexual identity take shape. That development is suppressed — not ‘paused’.
• No comparison with natural development: pre-protocol research showed that the majority of children with dysphoria naturally grow out of it during puberty without medication (desistance). Suppressing puberty blocks precisely that natural route.

Known physical effects

• Bones: significant loss of bone density during treatment, at the very time when bone mass normally peaks. Whether this fully recovers is unknown.
• Brain: adolescent brain development — including executive functions, emotional regulation and social cognition — takes place in parallel with and in interaction with sex hormones. Research (including studies in sheep by Hough and cognitive research by Baxendale) points to lasting effects. There are no long-term human studies capable of resolving this uncertainty.
• Fertility: when blockers are immediately followed by sex hormones, the gonads have never developed. Cryopreservation of reproductive cells is then practically impossible. Permanent infertility is a probable consequence of the complete Dutch Protocol pathway; see fertility and transition.
• Sexual function: in boys, the penis grows during puberty. Suppression means that a possible later vaginoplasty has less tissue available. In both sexes, anorgasmia and reduced sexual function have been documented after completing the full pathway.
• Height and body structure: growth and closure of the growth plates proceed abnormally under blockers.

Scientific debate

The NICE evaluation (2020) assessed the available evidence as ‘very low quality’. The Cass Review (2024) reached the same conclusion and recommended that puberty blockers for gender dysphoria should only be used in a research setting. Michael Biggs (Oxford) analysed the British and Dutch data and concluded that the original claim of improved psychological well-being could not be replicated.

International policy changes

• UK: indefinite ban outside research settings (2024); see the British ban on puberty blockers. Regarding the research trial, the court ruled in 2026: the door is open to a trial involving 226 children.
• Sweden: use of the Dutch Protocol for minors restricted to exceptional cases (Socialstyrelsen, 2022).
• Finland: use permitted only in strictly indicated exceptional cases (COHERE, 2020).
• Denmark: sharply restricted (Danish Health Authority, 2023).
• Norway: the investigation board Ukom recommended treating the intervention as experimental (2023); the guideline has not been withdrawn. See Ukom’s report.

In the Netherlands — the country where the approach originated — puberty blockers are still available through specialised gender clinics, without a comparable formal reassessment. The Health Council concluded in June 2026 that transgender care for young people is carefully organised. In Australia, a national review of the guideline for puberty blockers is under way.

Alternatives

Sweden, Finland and the UK now favour an approach that begins with psychotherapeutic support, focuses on underlying issues (autism, trauma and internalising disorders), and allows time for the child’s natural development (watchful waiting). Social transition is also viewed more cautiously in these countries, because research suggests that early social transition itself may increase the likelihood that dysphoria persists.