What Is Sermorelin? GHRH Analogue and Geref, Explained

By DoseGauge Editorial · Updated 2026-06-13 · 7 min read

Sermorelin is a synthetic analogue of growth-hormone-releasing hormone (GHRH), specifically the GRF 1-29 fragment. It acts on the pituitary gland to prompt the release of growth hormone, which in turn raises circulating IGF-1. It was once sold as the FDA-approved product Geref (sermorelin acetate), and today it is used off-label through compounding pharmacies rather than as a currently approved finished product. The defining feature is that sermorelin works one step upstream: it stimulates the body to release its own growth hormone, rather than supplying growth hormone directly the way recombinant HGH does. This page explains what sermorelin is and how it works. It is informational and educational only, not medical advice, and it does not recommend sermorelin or any dose.

How sermorelin works

Sermorelin is a synthetic analogue of growth-hormone-releasing hormone, the natural signal the hypothalamus sends to the pituitary gland. Chemically it corresponds to GRF 1-29, a shortened fragment of that natural hormone that retains the part needed to activate the receptor. When sermorelin binds the GHRH receptor on the pituitary, it stimulates the gland to release growth hormone. That growth hormone then acts on the liver and other tissues, which raises levels of insulin-like growth factor 1 (IGF-1). The RxList Geref clinical pharmacology summary describes this directly: sermorelin acetate increases plasma growth hormone concentration by stimulating the pituitary gland to release GH.

Timing is one of the more distinctive things about sermorelin. The peptide itself clears the bloodstream quickly, with a short plasma half-life of roughly 11 to 12 minutes after either intravenous or subcutaneous administration, per the Geref prescribing information as referenced by RxList. The signal it sets off, though, outlasts the peptide. The pulsatile growth hormone release it prompts from the pituitary continues for roughly 2 to 4 hours after injection. In other words, a drug that is gone from the blood in minutes can still drive a growth hormone pulse measured in hours.

Sermorelin versus HGH

The clearest way to understand sermorelin is to contrast it with recombinant human growth hormone (HGH). Injected HGH supplies the hormone directly: it puts growth hormone into the body from the outside. Sermorelin works one step upstream. As a GHRH analogue, it does not contain growth hormone at all; instead it signals the pituitary to release the body's own growth hormone in its natural pulsatile pattern.

That is a meaningful mechanistic difference. Because sermorelin relies on the pituitary to do the releasing, the response stays within the body's own regulatory loop rather than bypassing it. This page describes that distinction at a high level and does not claim one approach is safer or more effective than the other. Whether any growth-hormone-pathway drug is appropriate is a decision for a licensed clinician.

The Geref history and current status

Sermorelin is not a new or purely experimental molecule. It was approved by the FDA and sold as Geref (sermorelin acetate) for two specific indications: growth promotion in children with growth hormone deficiency, and diagnostic pituitary testing. The historical Geref prescribing information specified a pediatric dose of 30 mcg per kilogram of body weight, injected subcutaneously once daily at bedtime, for children with growth hormone deficiency.

Geref was later discontinued commercially. It is commonly reported, and consistent with the label-of-record framing, that the product was withdrawn in 2008 for business reasons unrelated to safety or efficacy, not because of any safety or effectiveness problem. That distinction matters: a discontinuation for business reasons is not the same as a drug being pulled because it was found unsafe or ineffective.

Here is the part that is easy to get wrong. Because Geref is no longer marketed, there is no currently approved finished sermorelin product. The sermorelin used today is supplied through compounding pharmacies, and current adult anti-aging and wellness use is off-label. The historical pediatric approval does not establish that sermorelin is FDA-approved for adults, and it does not establish efficacy for anti-aging or body-composition goals. Typical compounded adult doses cited in current practice fall around 200 to 500 mcg once daily at bedtime, but those are off-label and outside any approved finished product. This page does not recommend any such use.

How it is given

Sermorelin is given by subcutaneous injection. The historical FDA-approved Geref label specified once-daily dosing at bedtime, and current compounded use generally follows the same bedtime, once-daily pattern. The bedtime timing is not arbitrary: it aligns with the body's natural nocturnal growth hormone peak. Endogenous growth hormone secretion is highest during slow-wave (deep) sleep, and somatostatin, the main inhibitor of growth hormone, falls during sleep. Injecting in the evening lines the sermorelin signal up with the overnight window when the pituitary is most ready to release growth hormone.

This page does not specify a dose for you. The amount drawn depends on the vial strength and the volume of bacteriostatic water used to reconstitute it, which together set the concentration. The sermorelin dosage calculator on this site does that conversion from the vial strength and water volume you enter, returning the units to draw on a U-100 insulin syringe.

For a closer look at the reported effects people associate with it, see sermorelin benefits, and for how sermorelin compares to other peptides in the GHRH class.

Frequently asked questions

What is sermorelin used for?

Sermorelin is a GHRH analogue (the GRF 1-29 fragment) that stimulates the pituitary to release the body's own growth hormone, which raises IGF-1 (per the Geref clinical pharmacology summary referenced by RxList). It was originally FDA-approved as Geref for growth promotion in children with growth hormone deficiency and for diagnostic pituitary testing. Adult anti-aging or wellness use was never an approved indication. Current adult use is off-label and supplied through compounding, and this page does not recommend it for any purpose.

Is sermorelin the same as Geref?

Sermorelin is the active ingredient, and Geref (sermorelin acetate) was the brand name of the FDA-approved product it was sold under. So they refer to the same molecule, with Geref being the historical marketed product. Geref was discontinued commercially in 2008, so there is no currently approved finished sermorelin product on the market.

Is sermorelin FDA-approved?

Geref (sermorelin acetate) was FDA-approved for growth promotion in children with growth hormone deficiency and for diagnostic pituitary testing. That product was discontinued in 2008, commonly reported as a business decision unrelated to safety or efficacy. Adult GH deficiency, adult GH insufficiency, and anti-aging use were never approved indications. There is no currently approved finished sermorelin product, so current adult use is off-label and supplied through compounding pharmacies. The historical pediatric approval does not establish that sermorelin is approved for adults or effective for anti-aging.

Is sermorelin the same as HGH?

No. Recombinant human growth hormone (HGH) supplies growth hormone directly, putting the hormone into the body from the outside. Sermorelin works one step upstream as a GHRH analogue: it signals the pituitary to release the body's own growth hormone, which then raises IGF-1. They act at different points in the same pathway and are not interchangeable. A licensed clinician is the right person to discuss either one.

Informational and educational only. Not medical advice. DoseGauge computes from the values you enter and does not recommend a dose. Talk to a licensed clinician before using any peptide or GLP-1 medication.