Peptide reference → Hormone & growth → Gonadorelin

Gonadorelin

Research use

Gonadotropin releasing hormone (10 amino acids) · also known as Relefact

Last updated 29 October 2026

Gonadorelin is a synthetic copy of GnRH, the brain's signal that drives the release of fertility hormones. It is used as a medicine in some settings for fertility and diagnostic tests, and is popular in private clinics abroad alongside testosterone therapy. Its UK availability is limited, and it is often sold online for research use.

Key points

Gonadorelin is a ten amino acid peptide that copies gonadotropin releasing hormone (GnRH).
It prompts the pituitary to release the fertility hormones FSH and LH, in natural pulses.
It has been used medically for fertility and for diagnostic testing of the pituitary, though its availability in the UK is limited.
It is popular in some private clinics alongside testosterone therapy, and is widely sold online for research use.

Quick facts

What it is: GnRH analogue, 10 amino acids
Used for: Fertility and diagnostic testing; alongside TRT abroad
UK status: Limited availability; often sold for research use
Human evidence: Established in fertility; limited alongside TRT

How it works

GnRH is released in pulses from the brain and tells the pituitary to make FSH and LH, which in turn drive the ovaries and testes. Gonadorelin copies this pulse. Given in the right way it can support the body's own hormone production, which is the idea behind using it alongside testosterone therapy to keep the testes active.

What the evidence shows

Its established medical uses are in fertility and in diagnostic testing of pituitary function. Its use alongside testosterone therapy is popular in private practice but rests on smaller, less controlled studies rather than large trials.

What it does not settle

The evidence for use alongside testosterone therapy is limited.
The best doses and schedules for that purpose are not well established.
Long term outcomes of such use are not well documented.

Side effects

Common

Injection site reactions, headache and flushing.
Possible mood or hormone related effects.

Less common but serious

Used incorrectly it can disrupt rather than support hormone balance.
Where there is no licensed product to hand, the dose, purity and contents of material bought online cannot be verified.

Report any suspected side effect through the MHRA Yellow Card scheme.

UK legal status and access

Gonadorelin has established medical uses in some settings but limited availability in the UK, and much of what is sold online is labelled for research use. Hormone and fertility concerns are best handled by a registered clinician using licensed treatments.

Common questions

What is gonadorelin?

A synthetic copy of GnRH, the brain's signal that drives the release of the fertility hormones FSH and LH.

Why is it used with testosterone therapy?

Testosterone therapy can switch off the body's own signal to the testes. Gonadorelin is used to try to keep that signal going, though the evidence is limited.

The licensed route

Hormone and fertility concerns are best assessed by a registered clinician, who can advise on licensed treatments and proper monitoring.

Factual reference only, not medical advice. We give no dosing for unlicensed compounds.

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