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Evidence: MediumPeptideVeterinary OnlyGnRH agonistVeterinary implant in the EUProhibited in male athletes

Deslorelin

A long-acting hormone shut-off switch, now mostly used to chemically castrate dogs

Deslorelin is a synthetic version of gonadotropin-releasing hormone that, given continuously, switches off the reproductive hormone axis. In the 1990s US government researchers used it in children with early puberty; today its main use is Suprelorin, an implant authorised in the EU to make male dogs temporarily infertile.

At a Glance Read Research →
Overview

What is it?

Gonadotropin-releasing hormone pulses from the brain drive the pituitary to release LH and FSH. Long-acting agonists such as deslorelin, leuprolide and triptorelin overwhelm that signal: after a brief surge, the pituitary stops responding and sex hormones fall. That is useful in prostate cancer, endometriosis and early puberty.

At the US National Institutes of Health in the 1990s, deslorelin was given by daily injection to children with central precocious puberty and, alongside anti-androgen drugs, to boys with familial male-limited precocious puberty. It never became a marketed human drug, and the EMA lists it only as the veterinary implant Suprelorin.

Most of its recent literature is veterinary and zoo medicine: fertility control and behaviour in dogs, cats, birds and other species, where results are not always what keepers hope. It is named on the WADA Prohibited List for male athletes.

Structured data

At a Glance

Every value in this table is printed from the Grey Peptides dataset, the same record the compound explorer and comparison tool read, so the three can never disagree.

ClassA synthetic agonist of gonadotropin-releasing hormone that, given continuously, shuts down the reproductive hormone axis; authorised in the EU as a veterinary implant and studied in children with precocious puberty at the US National Institutes of Health.
FormulaC64H83N17O12
Molecular weight1282.4 g/mol
Half-lifenot reported in the sources read
Studied dose4-8 µg/kg/day (daily subcutaneous injection (NIH paediatric studies), subcutaneous)
US statusVeterinary Only
Evidence levelMedium
Last reviewed2026-10-04

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.

Evidence

Published Research

Studies whose titles name deslorelin, read from their PubMed abstracts on October 4, 2026.

Human1999

Boys with familial precocious puberty

10 boys with familial male-limited precocious puberty took spironolactone and testolactone for at least six years, with deslorelin 4 µg/kg/day added once central puberty began. Growth and bone maturation rates normalised, and predicted adult height rose from 160.7 to 173.6 cm.

PMID: 9920079
Animal2026

Neutered dogs, randomised

In a double-blind randomised trial in 30 neutered male dogs that attracted other males, a 4.7 mg implant reduced attractiveness in 11 of 15 against 5 of 15 with placebo (odds ratio 5.47); LH fell to basal levels while FSH stayed raised.

PMID: 42119283
Animal2026

Not for aggressive rays

Implants were tested in three male cownose rays to curb aggression, with hormone measurements over time; the authors concluded deslorelin is contraindicated for mitigating aggression and reproductive behaviour in this species.

PMID: 41926257
Animal2025

Measuring it in the blood

Zoo veterinarians built a mass-spectrometry assay for deslorelin in serum and ran a pilot pharmacokinetic study of implants in goats, because doses for zoo species are extrapolated from the dog product.

PMID: 41065688
Safety

Side Effects & Contraindications

Reported Side Effects

From the studies above and its drug class.

● Suppressed sex hormones, the intended effect, with loss of fertility while treatment lasts
● In animals an initial stimulation phase can occur before suppression, as with other GnRH agonists

Contraindications & Cautions

No human label exists.

● Not authorised for human use in the US or EU; prohibited for male athletes
Questions

Frequently Asked Questions

?What is deslorelin used for?

Mainly as Suprelorin, a veterinary implant that temporarily stops fertility in male dogs and other animals. It was studied in children with precocious puberty in the 1990s.

?Is deslorelin approved for people?

No. It has no human approval in the US or EU; the EMA lists it only as a veterinary medicine.

?How does deslorelin work?

As a long-acting GnRH agonist it first stimulates and then desensitises the pituitary, so sex hormones fall.

?Is deslorelin banned in sport?

Yes, for male athletes: WADA names it under S2.2.1.

Bibliography

References

  1. [other] PubChem CID 25077495, Deslorelin: formula C64H83N17O12, molecular weight 1282.4. Read October 4, 2026. https://pubchem.ncbi.nlm.nih.gov/compound/25077495
  2. [other] European Medicines Agency medicines list (JSON report): Suprelorin (deslorelin acetate), category Veterinary, status Authorised. Read October 4, 2026.
  3. [other] World Anti-Doping Agency 2026 and 2027 Prohibited Lists, section S2.2.1: GnRH agonist analogues prohibited in males, deslorelin named. Read October 4, 2026.
  4. [clinical-trial] Leschek EW, et al. "Six-year results of spironolactone and testolactone treatment of familial male-limited precocious puberty with addition of deslorelin after central puberty onset." J Clin Endocrinol Metab, 1999;84(1):175-8. PMID: 9920079.
  5. [pubmed] Leber J, et al. "The efficacy of deslorelin implants in neutered male dogs that sexually attract other male dogs: a randomized controlled trial." Theriogenology, 2026;262:117975. PMID: 42119283.
  6. [pubmed] Hyatt MW, et al. "THE GONADOTROPIN RELEASING HORMONE AGONIST, DESLORELIN ACETATE, IS CONTRAINDICATED FOR MITIGATION OF AGGRESSION AND REPRODUCTIVE BEHAVIOR IN MALE COWNOSE RAYS (RHINOPTERA BONASUS)." J Zoo Wildl Med, 2026;57(1):76-86. PMID: 41926257.
  7. [pubmed] Rooney TA, et al. "DEVELOPMENT AND VALIDATION OF DESLORELIN ACETATE ASSAY AND A PILOT STUDY ON THE PHARMACOKINETICS OF DESLORELIN ACETATE IMPLANTS AND FECAL HORMONE MONITORING IN THE DOMESTIC GOAT (CAPRA HIRCUS)." J Zoo Wildl Med, 2025;56(3):548-557. PMID: 41065688.
  8. [pubmed] Feuillan PP, et al. "Reproductive axis after discontinuation of gonadotropin-releasing hormone analog treatment of girls with precocious puberty: long term follow-up comparing girls with hypothalamic hamartoma to those with idiopathic precocious puberty." J Clin Endocrinol Metab, 1999;84(1):44-9. PMID: 9920060.

Sources & Citations

Studies from their PubMed abstracts, October 4, 2026; EU status from the EMA medicines list and WADA status from the 2026 and 2027 Lists, read the same day.

Medical Disclaimer: This content is for educational and informational purposes only. It is not medical advice, and nothing here is an instruction to obtain or use any compound. Consult a licensed healthcare provider before making health decisions.

Last reviewed: 2026-10-04