Peptide Science Desk

Gonadorelin

A lab-made copy of a brain hormone that controls sex hormones. The human version (Factrel) is listed by the FDA as discontinued.

AI illustration of a vial labeled Gonadorelin
AI illustration
FDA statusOff market

The human drug (Factrel) is discontinued in the US. Today’s Factrel is for cattle.

Proof it works in people for keeping testosterone and fertility up in menNone found

No trial for the online use. Good pump studies for other uses.

Safety data in peopleVery little

No current human label. Pump studies are small.

Three separate grades: the law (the human drug is off the market), proof (none for the online use), and safety data (little). Proof for one use does not carry over to another.

By the Peptide Science Desk Editorial TeamFact-checked against FDA and official sources · Not yet reviewed by a licensed clinician. How we check facts

What is it?

Gonadorelin is a lab-made copy of GnRH, a 10-building-block signal from the brain. The brain sends GnRH in short bursts, not a steady stream. Each burst tells the pituitary gland to release LH and FSH, which run the testicles and ovaries.

Why do people use it?

In medicine, a pump that gives tiny pulses of GnRH has been used to start sperm making in men, and ovulation in women, whose brains do not send the signal. Online, men on testosterone use gonadorelin shots instead of HCG, hoping to keep their testicles working. That use has not been tested.

Does it really work?

It works when given the way the brain does it: small pulses from a pump. In men who never made GnRH, that started sperm in most cases. In women with missing periods, it led to ovulation in most cycles. We found no trial in men using it alongside testosterone.

Studies in people

We found no study of gonadorelin in men on testosterone. The 5 studies below used GnRH pulse pumps in people whose brains do not make it.

Study designPeopleWhat they measuredWhat they foundYearJournalPubMed
Case series (Germany), pump vs hormone shots42 men with low GnRH or pituitary problemsSperm and pregnancySperm appeared in 54 of 57 treatment rounds. Partners got pregnant in 26 of 36.1998Eur J EndocrinolPMID 9758439
Comparison study, not randomized34 teen boys with low GnRH (12 pump, 22 HCG)Testicle size, testosterone, side effectsThe pump group had bigger testicles. Side effects were similar.2015J Clin Endocrinol MetabPMID 25978110
Look-back study202 men with low GnRH (20 pump, 182 hormone shots)Time until sperm appearedSperm came sooner with the pump: about 6 vs 18 months.2017Asian J AndrolPMID 28051040
7-day pump test, 3 hospitals28 men with low GnRHLH, FSH and safetyLH and FSH rose. No side effects linked to the pump treatment.2021Ann Transl MedPMID 34277762
Review of 35 studies1,002 women with missing periods from low GnRHOvulation, pregnancy, side effectsOvulation was common. Ovary over-stimulation was rare and mild. Twins were a bit more common.2018Fertil SterilPMID 29605411

Official labels

We read each of these 5 papers on PubMed on October 28, 2026.

Is it safe? Side effects

  • There is no current FDA label for people to check side effects against.
  • In pump studies, side effects were few. In women, twins happened a bit more than usual.
  • A shot now and then is not the same as a pump giving many small bursts a day, so pump study results may not apply.
  • Products sold online for people are not FDA-approved.

Banned in sports? Drug tests

Banned for male athletes.

Yes, for men. WADA bans gonadorelin at all times for male athletes (section S2.2.1: peptides that raise testosterone in males). Women athletes should still check with USADA.

Check work, NCAA, and military rules for Gonadorelin

Talk to your doctor

If you are on testosterone and want to keep fertility, ask a fertility or hormone doctor about options that have been tested, such as HCG. We never share doses or tell you where to buy. Print our doctor questions sheet.

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More questions

Is gonadorelin the same as HCG?

No. Gonadorelin copies a brain signal (GnRH). HCG acts more like a body hormone called LH. They work at different steps.

Is gonadorelin FDA approved?

The human product (Factrel) is listed by the FDA as discontinued. Today’s Factrel is an animal drug for cattle.

Is gonadorelin a steroid?

No. It is a peptide, not a steroid.

Related peptides

Guides and tools

Sources

Not medical advice. Medical disclaimer.