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Reproductive & sexual health

Goserelin

A GnRH agonist delivered as a small implant under the skin of the abdomen, suppressing sex hormones in prostate and breast cancer and certain gynaecological conditions.

L5Practice-changingApproved medicineApprovedHigh confidenceLast reviewed 2026-08-23
Implant

Also known as: Zoladex, goserelin acetate

Evidence passport

Last reviewed 2026-08-23

Evidence level
L5Practice-changing
Confidence
High confidence
Human efficacy
82/100
Human safety
78/100
Regulatory status
Approved medicine
Development
Approved
Routes
Implant
Evidence base
Includes human data
Furthest stage
Approved
Source curation
Sources fully curated
Clinical maturity
Established hormone-suppression implant

Overview

Human evidence82/100
Preclinical evidence72/100
Human safety evidence78/100

Clinical maturity: Established hormone-suppression implant

Routes & formulations

Studied / approved routes

Implant

Administered as a biodegradable depot implant placed under the skin of the anterior abdominal wall; release intervals differ by product strength.

Route availability is not evidence of efficacy, and evidence from one route does not transfer to another. The Registry never provides dosing or sourcing information.

Peptide lifecycle

  1. Discovery

  2. Preclinical

  3. Phase I

  4. Phase II

  5. Phase III

  6. Approved

Approved

What it is

A GnRH-agonist peptide formulated into a slow-release implant that continuously suppresses pituitary gonadotrophin output.

What people claim

  • Suppresses sex-hormone production in hormone-sensitive cancers
  • Manages endometriosis and related gynaecological conditions

What the evidence actually says

Long-standing controlled evidence and clinical use support its hormone-suppression indications; the implant format is a good example of a peptide medicine engineered around a delivery problem.

Human evidence

  • Randomised trials and decades of use in prostate cancer, breast cancer and gynaecology.

Preclinical evidence

  • GnRH-agonist pharmacology and depot-release formulation science.

Animal and cell findings are Level 1–2 evidence.

Mechanism and pathways

  • Continuous GnRH-receptor agonism desensitises pituitary gonadotrophs, suppressing LH/FSH and downstream sex steroids.

Safety and unknowns

  • Labelled class effects mirror hormone deprivation: hot flushes, bone-density loss with prolonged use and an initial flare.
  • Implant insertion is a minor clinical procedure with its own labelled considerations.

Cancer relevance

No concern identified

Used as a treatment in hormone-sensitive cancers; no cancer-promotion signal within approved use.

Regulatory status

FDA-approved (Zoladex) as a subcutaneous implant for indications including palliative treatment of advanced prostate cancer and certain breast-cancer and gynaecological uses, depending on product strength and label.

Evidence grade

L5Practice-changingHigh confidence

Replicated large randomised trials, pivotal Phase 3 programmes, or a major regulatory decision.

What would change our rating?

  • Not applicable at this evidence tier.

References and sources

Sources fully curated

Source hierarchy: regulatory documents and trial registries first, peer-reviewed work next, sponsor material flagged as non-independent. We never use supplier or clinic marketing as evidence, and where a verified source has not yet been curated we say so rather than inventing one.

Evidence change history

No recorded changes yet. Baseline position set on 2026-08-23.