Azagly-nafarelin

Mechanism of action

A GnRH agonist: continuous release from an implant down-regulates pituitary GnRH receptors, cutting LH and testosterone (2009 dog study).

Primary uses

• Induction and synchronisation of ovulation in female salmonid fish (former EU authorisation)
• Dogs: the former EU authorisation covered bitches; studies used it to suppress testicular function in male dogs

Typical dosing

Educational information, not medical advice. The doses on this page come from approved labels, published studies and, where no study exists, amounts reported by users. None is a recommendation for you. An unapproved compound has no established safe or effective human dose, and products sold for “research use only” are not made or tested for people. Talk to a doctor before acting on anything on this site, including before you start, stop or change any medicine or dose. Full medical disclaimer.

Regulatory status

Never approved for people. EU: Gonazon (azagly-nafarelin) was authorised as a veterinary medicine on July 20, 2003, for female salmonid fish (induction and synchronisation of ovulation) and dogs (bitches), and is now withdrawn (EMA medicines list, category veterinary). Drugs@FDA holds no record.

Status as of this entry's last review, October 28, 2026. Approvals, compounding rules and sport rules change; the regulatory tracker is checked more often.

What we checked

Azagly-nafarelin is a withdrawn veterinary GnRH agonist; this section records what can be checked.

Identity, computed

Its aza-glycine and naphthylalanine residues are outside a residue calculator, so the formula and weight are PubChem's.

Regulatory status, read October 28, 2026

Drugs@FDA: 0 records for “azagly-nafarelin”. EMA medicines list: 1 record for “azagly-nafarelin”. Run for semaglutide, the same queries return 6 and 5 records (and the registry search 80 trials), so a zero here is an absence, not a broken search. WADA 2026: section S2.2.1; WADA 2027: section S2.2.1.

What the studies show

Reversible down-regulation of endocrine and testicular function in eight beagles with a removable implant (Ludwig et al., 2009).

Clinical use in 53 male dogs with prostatic hyperplasia, hypersexuality, aggression or for fertility suppression (Goericke-Pesch et al., 2010).

What we looked for and did not find

No human study and no current authorisation.

References

1. [other] PubChem CID 156613532, Azagly-nafarelin: formula C66H84N18O13, molecular weight 1337.5. Read October 28, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/156613532
2. [other] European Medicines Agency, medicines list (JSON report, downloaded October 28, 2026): Gonazon (azagly-nafarelin): category veterinary, status withdrawn; marketing authorisation date July 20, 2003; species dogs and salmonid fish.
3. [clinical-trial] Ludwig C, et al. "Reversible downregulation of endocrine and germinative testicular function (hormonal castration) in the dog with the GnRH-agonist azagly-nafarelin as a removable implant "Gonazon"; a preclinical trial." Theriogenology, 2009;71(7):1037-45. PMID: 19233456.
4. [pubmed] Goericke-Pesch S, et al. "Evaluation of the clinical efficacy of Gonazon implants in the treatment of reproductive pathologies, behavioral problems, and suppression of reproductive function in the male dog." Theriogenology, 2010;73(7):920-6. PMID: 20097413.
5. [other] US FDA, Drugs@FDA (openFDA): no application for azagly-nafarelin. Read October 28, 2026.

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