A spatial reading of one prescription peptide, in 29 amino acids and twelve minutes.

The short version

Sermorelin is a 29-amino-acid synthetic peptide that reproduces the active fragment of the body's own growth hormone-releasing hormone (GHRH — the signal the hypothalamus sends to tell the pituitary to make growth hormone). It was once an FDA-approved prescription drug called Geref, used to treat children with growth failure. The company pulled it from the market in 2008 for commercial reasons, not safety ones. Today it is prepared by compounding pharmacies and is not sold as a finished branded product anywhere in the United States.

The studies on sermorelin are real but limited. In growth-hormone-deficient children it accelerated height growth. In small trials of older adults it raised growth hormone and IGF-1 levels, with modest reported effects on body fat and energy. Long-term evidence for anti-aging use does not yet exist. Read the effects and safety page for a plain-English account of what the trials measured and what research-use communities report.

Twenty-nine amino acids, one receptor

Sermorelin is a 29-residue synthetic polypeptide that reproduces the amino-terminal fragment of endogenous growth hormone-releasing hormone (GHRH). The full hypothalamic peptide is 44 residues long; the first 29 carry essentially all of its biological activity, and that is the molecule the chemistry preserves ^[1].

The target is narrow. Sermorelin binds the GHRH receptor on somatotroph cells of the anterior pituitary, activating Gs-protein coupled cAMP/PKA signaling and a parallel MAPK cascade ^[12]. The result is a physiologic pulse of stored growth hormone (GH) into circulation, followed by hepatic induction of insulin-like growth factor 1 (IGF-1). Because somatostatin negative feedback remains intact along the way, the resulting GH profile is pulsatile rather than flat — a structural difference from exogenous recombinant GH that recurs throughout the literature ^[9].

The pharmacokinetics are conspicuously brief. After both intravenous and subcutaneous administration the plasma half-life is approximately 11 to 12 minutes, with rapid degradation by dipeptidyl peptidase-4 and neutral endopeptidase; subcutaneous bioavailability sits near 6 percent, with peak plasma concentration at 5 to 20 minutes ^[5]. Less than 5 percent of the dose remains circulating by one hour. The downstream GH pulse, however, persists for hours after the parent peptide has already cleared.

An approval, a withdrawal, a compounded second act

Sermorelin acetate received initial FDA approval on September 26, 1997 under NDA 020443, for the treatment of idiopathic growth hormone deficiency in children with growth failure ^[3]. The pivotal pediatric program supporting that approval was the multicenter International Study Group trial in 110 prepubertal GH-deficient children, which demonstrated sustained increases in height velocity over 36 months of nightly subcutaneous administration ^[15].

The product was voluntarily discontinued in 2008. The FDA's 2013 Federal Register determination on that discontinuation is explicit and is the document worth reading carefully: the withdrawal was a commercial decision, not a safety or efficacy finding ^[3]. Inferior height-velocity response relative to recombinant somatropin in head-to-head pediatric comparisons was the substantive contributor; the formal regulatory withdrawal followed on June 18, 2009.

What survived is the active ingredient itself. Sermorelin acetate remains legally available in the United States via patient-specific compounding under section 503A of the Federal Food, Drug, and Cosmetic Act, and via FDA-registered outsourcing facilities under section 503B, because the bulk drug substance is a component of a previously-approved drug product ^[13]. The FDA's January 7, 2025 final interim guidance closed the forward-looking Category 1/2/3 nomination system for newly nominated bulks, but explicitly preserved the previously-approved-active pathway under which sermorelin sits.

The adult literature is smaller and more interesting than it looks

The pediatric trials carried sermorelin to market; the more recent investigational literature has examined what GHRH-class stimulation does in older adults whose somatotrophic axis has involuted.

The Khorram cohort published in the Journal of Clinical Endocrinology & Metabolism in 1997 randomized 19 men and women aged 55 to 71 to a 16-week course of nightly 10 mcg/kg subcutaneous GHRH(1-29). Nocturnal GH and IGF-1 rose; men gained on average 1.26 kg of lean body mass, with measurable improvements in insulin sensitivity and patient-reported well-being ^[6]. A subsequent six-month NIH-funded program reported by Vitiello and colleagues used 14 mcg/kg (approximately 1 mg) nightly in older adults and reported a doubling of 24-hour GH secretion, a roughly 40 percent rise in IGF-1, a 5 percent reduction in body fat, and 5-to-7 percent improvements in cognitive processing speed ^[8].

Class-validating data come from the structurally related stabilized GHRH analog tesamorelin. In the Baker trial published in Archives of Neurology, 20 weeks of daily 1 mg subcutaneous administration in 152 older adults — 66 with mild cognitive impairment — significantly improved executive function (p=0.005), raised IGF-1 by 117 percent within the physiologic range, and reduced body fat by 7.4 percent ^[7]. The cognitive benefit was comparable between participants with mild cognitive impairment and healthy older adults, an observation that has shaped much of the contemporary interest in the GHRH receptor as a therapeutic target.

How to read this site

Rx Sermorelin is an independent editorial project. It is not a clinic. It does not employ clinicians. It does not manufacture, sell, ship, or dispense any compounded product, and it is not affiliated with any pharmacy, telehealth service, or vendor.

The 'rx' in the wordmark is editorial framing — an acknowledgement that sermorelin's regulatory record is a prescription record, and that the contemporary access pathway runs through state-licensed pharmacies operating under sections 503A and 503B. Treating that record seriously requires reading it as pharmacy law and clinical pharmacology rather than as marketing copy.

The site is organized around the primary record. The /research page summarizes mechanism, pharmacokinetics, and the trial literature. The /dosage page describes doses as they appear in studies and in the historical NDA 020443 label, in research-context language only. The /effects page covers what the trials measured, what research-use communities report, and the dated cautions. The /faq answers the questions readers most often arrive with. The /references page lists every cited source with its DOI and PubMed identifier. Everything is editorial commentary on publicly available science.