Puberty Suppression in Adolescents — Evidence Review

An Evidence Review grading the certainty of the evidence on puberty suppression — gonadotrophin-releasing hormone agonists (GnRHa) — in adolescents experiencing gender dysphoria or incongruence. The review's method is to hold two questions apart. The evidence question — what the studies show about benefits and harms, and how certain that is — is answered outcome by outcome, with per-claim certainty grading. The policy question— what should follow from evidence of that quality — turns partly on further empirical questions and mostly on risk tolerance and values that the evidence cannot settle. The review answers the first and characterises the second without pretending the evidence resolves it, and applies the same evidential standard in both directions. Graded findings: GnRHa reliably suppress gonadal puberty, and adult height attainment appears broadly unaffected. Bone-density accrual slows during treatment and largely, though not uniformly, recovers once gender-affirming hormones follow, with a lumbar-spine shortfall that can persist. The blocker alone does not ablate the gonad, but the standard pathway of early initiation followed directly by gender-affirming hormones may leave no window for conventional fertility preservation. The evidence that puberty suppression itself improves psychological outcomes — the benefit for which it is principally given — is of low certainty. Long-term fracture, fertility, sexual-development and neurocognitive outcomes are insufficiently studied. Continuation is high, and the widely cited 98% figure is a persistence-after-initiation rate rather than a blocker-to-hormone transition rate; what it means causally is unresolved. Scope and limitations. This is a single-author narrative evidence review, not a systematic review. It uses no registered protocol, no reproducible database search, no independent dual screening and no formal risk-of-bias instrument; its certainty marks (robust / moderate / limited) are editorial judgements, not formal GRADE ratings. Adolescent gender-affirming hormone therapy is out of scope and is committed to a separate review. Data extrapolated from cisgender, precocious-puberty or animal populations are flagged throughout.