Peptides

Gonadorelin Acetate

Also called GnRH · LHRH

Gonadorelin often comes up when a TRT clinic offers it instead of hCG to support testicular function or fertility. It acts upstream at the pituitary, so the delivery schedule matters: a few injections per week are not the same treatment as the frequent pulses used in fertility research.

Open the plotter Sources

Dosage & duration

Two distinct contexts; neither is a proven universal TRT fertility regimen.

One reported TRT-related use

Reported use · unapproved regimen

Dose: 100 mcg per administration
How often: Twice weekly; route and salt not specified
How long: About four weeks into combined therapy at posting; full course not stated

Reported alongside testosterone, anastrozole and sermorelin/ipamorelin. This is not evidence of fertility preservation.

UK gonadorelin hydrochloride diagnostic product

Product label

Dose: 100 mcg
How often: Single under-skin or intravenous administration
How long: One supervised test

One supervised pituitary-response test. Hydrochloride product context, not proof that a gonadorelin acetate preparation is interchangeable.

Sources: 1

Gonadorelin doses are in mcg; hCG IU amounts are not interchangeable. The diagnostic example describes a hydrochloride product, not an interchangeable acetate prescription.

More quick facts

Common question: Can it replace hCG?; Sources : 1 · 2
Delivery matters: Pump pulses versus occasional shots; Sources : 1 · 2
Useful endpoint: Semen testing; Sources : 1 · 2

The practical difference

Gonadorelin and hCG act at different points

How the signal differs	Gonadorelin	hCG
Where it acts	At the pituitary	At the testes
Signal supplied	Prompts LH and FSH release	Provides an LH-like signal

Frequent pump pulses in selected fertility studies do not validate occasional TRT-adjunct injections or equal fertility protection. Sources and context

Why clinics and TRT users discuss it

The intended goal is keeping reproductive hormone signalling active. Gonadorelin prompts the pituitary to release LH and FSH; hCG acts differently, providing an LH-like signal at the testes. Swapping names on a prescription does not establish equal fertility protection.

A pulse is not a week of coverage

Successful fertility research uses repeated pulses delivered by a pump in selected patients. An occasional bolus can produce a hormone response without proving sustained sperm production during TRT. A short half-life alone cannot tell you the right schedule.

What would show that it is helping?

If fertility is the goal, semen testing matters. Testicular size, libido or a transient LH rise do not confirm that sperm production is preserved. The diagnosis and other hormones being taken affect interpretation.

Model details: Gonadorelin Acetate · relative timing

Compare timing and buildup for this compound. The values are not blood concentrations or a measure of strength.

Shows a relative timing scenario; absolute blood concentrations are not calibrated.

Timing assumptions and sources

Human gonadorelin hydrochloride SmPC: rapid plasma hydrolysis with about 4 min half-life; SC/IV diagnostic formulation.

One 1 mg input peaks at 1 relative unit after a single dose. Other amounts scale proportionally; overlapping doses add when accumulation is on. Different compounds use separate relative scales.

Timing half-life used: 0.06666667 hours
Absorption half-life assumed: 0.01666667 hours
Reference amount for the relative scale: 1 mg

Absorption half-life is assumed to be one quarter of the slower timescale (0.016666666666666666 h); it is not a measured absorption parameter.
A single 1-unit input has a peak of 1 relative unit; scaling and repeated-dose addition are mathematical assumptions. This normalization is independent of the example dose.
Acetate preparations are not demonstrated bioequivalent.
The LH diagnostic response is not gonadorelin concentration.
SC peak and availability remain uncalibrated.

Gonadorelin 100 µg UK SmPC 5.2
About 4 min half-life is reported for the human hydrochloride diagnostic formulation. No absolute matched dose/Cmax/Tmax set is supplied.

gonadorelin-relative-timing-2026-10 · version 1

Common questions

Is gonadorelin an hCG dose equivalent?

No. Different targets and units prevent a simple swap or dose conversion.

Does an LH rise prove fertility is protected?

No. A brief response and sustained sperm production are different outcomes.

Sources Labels, studies and notes behind this guide

Catalog evidence: Other human research. This describes the type of evidence, not a clinical review of every claim.

Summary and fact source checks: 2026-10-07. This records source checking, not medical review of the whole page.

Notes on the quick facts

Common question: Different mechanism; equal fertility protection is not established.
Delivery matters: Do not transfer evidence between these schedules.
Useful endpoint: Symptoms or testicular size alone cannot confirm fertility.

1. Human gonadorelin hydrochloride UK SmPC
Label specifies gonadorelin as hydrochloride: 100 mcg one-time adult SC/IV diagnostic test with timed LH sampling. This is not maintenance treatment, acetate-product equivalence, or veterinary Factrel.
2. Pulsatile gonadorelin fertility study
Men with congenital hypogonadotropic hypogonadism using frequent pump pulses; not occasional TRT-adjunct injections.
3. Gonadorelin 100 µg UK SmPC 5.2
About 4 min half-life is reported for the human hydrochloride diagnostic formulation. No absolute matched dose/Cmax/Tmax set is supplied.
4. Hoffman and Crowley, pulsatile GnRH study
Abstract: six men with idiopathic hypogonadotropic hypogonadism received long-term SC pump pulses; reproductive maturation and spermatogenesis findings do not validate occasional PCT injections.

Related compounds and examples