Gonadorelin (6-D-Phe)

Mechanism of action

A GnRH agonist analogue, stable against enzymatic degradation (2018 study); used to time ovulation in livestock.

Primary uses

• Ovulation control in cattle, pigs and horses (UK authorisations)
• Studied after insemination to raise conception rates in dairy cows

Typical dosing

Regulatory status

Approved only for animals. UK: Gonavet (gonadorelin [6-D-Phe]) and Oestracton (gonadorelin [6-D-Phe] acetate), for cattle, horses and pigs, are currently authorised (VMD). Not in the US Green Book's active-ingredient list or the EMA medicines list; 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

Gonadorelin (6-D-Phe) is a veterinary GnRH agonist; this section records what can be checked.

Identity, computed

PubChem returned no record under this name on the read date, so no formula is given.

Regulatory status, read October 28, 2026

Drugs@FDA: 0 records for “gonadorelin [6-D-Phe]”. EMA medicines list: 0 records for “gonadorelin [6-D-Phe]”. 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

Given at insemination or 12 days later to 1,634 cows in a large Saxon dairy herd to raise conception rates (Freick et al., 2014).

Zinc-triggered self-assembly of the peptide into nanostructures and fibrils (Yordanova et al., 2018).

A 1991 study of a dose reduction by complexing D-Phe6-GnRH with polyglycine (Naumann et al., 1991).

What we looked for and did not find

No human study.

References

1. [other] UK Veterinary Medicines Directorate, Product Information Database, currently authorised products searched by active substance, read October 28, 2026: Gonavet Veyx 50 µg/ml solution for injection for cattle, pigs and horses, VM 27569/4005, active substance gonadorelin[6-D-Phe]; Oestracton 52.4 micrograms/ml, VM 08007/5047, active substance gonadorelin[6-D-Phe] acetate. https://www.vmd.defra.gov.uk/ProductInformationDatabase/
2. [clinical-trial] Freick M, et al. "[Use of gonadorelin[6-D-Phe] at day 0 or 12 after insemination to increase the conception rate in a large dairy herd in Saxony/Germany]." Tierarztl Prax Ausg G Grosstiere Nutztiere, 2014;42(6):331-42. PMID: 25401927.
3. [pubmed] Yordanova Y, et al. "Zn(2+)-triggered self-assembly of Gonadorelin [6-D-Phe] to produce nanostructures and fibrils." Sci Rep, 2018;8(1):11280. PMID: 30050082.
4. [pubmed] Naumann W, et al. "[Dosage reduction of d-phe-6-GnRH for the regulation of ovulation by complexation with polyglycine]." Pharmazie, 1991;46(11):795-7. PMID: 1811231.
5. [other] US FDA, Drugs@FDA (openFDA): no application for gonadorelin [6-D-Phe]. Read October 28, 2026.

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