RESEARCH DIGEST / GHRH(1-29) ANALOG
Sermorelin is GHRH(1-29), the growth-hormone-releasing analog that anti-doping labs can now confirm in urine.
A hard-edged evidence board on the GHRH(1-29) literature: the receptor mechanism, the endocrine results, the ~10-12 minute half-life, and the LC-MS/MS detection methods — every figure carried back to the study that measured it.
The short version
Sermorelin is a lab-made copy of the working end of a hormone your own brain already makes. The body's hypothalamus releases GHRH (growth hormone-releasing hormone) to tell the pituitary gland to put out growth hormone; sermorelin is the first 29 building blocks of that hormone — the shortest piece that still does the full job [12]. Because it nudges your own gland rather than supplying a finished hormone, your natural on/off feedback stays intact. In studies it raised growth hormone and IGF-1; in older men, two weeks of it restored those values toward young-adult levels [2]. It clears the blood in about ten minutes [3], and anti-doping labs have validated urine tests that catch it down to fractions of a nanogram per milliliter [9].
What is sermorelin?
Sermorelin (sermorelin acetate) is GHRH(1-29)NH2 — the amidated first 29 amino acids of the 44-residue human growth hormone-releasing hormone, and the shortest fragment that keeps full activity at the GHRH receptor [12]. Its molecular weight is 3357.9 Da (CAS 86168-78-7; molecular formula C149H246N44O42S). It is classed as a pituitary growth-hormone secretagogue: a compound that prompts the gland to release the body's own growth hormone rather than supplying growth hormone directly.
Sermorelin was formerly FDA-approved — marketed in the United States under a brand name (NDA 020443) for evaluating and treating growth hormone deficiency and short stature in children [1]. It was withdrawn from the US market in 2008 for commercial reasons, not over any safety or efficacy problem, and is now prepared by compounding pharmacies; FDA treats it as a long-standing Category 1 bulk drug substance under the interim Section 503A policy finalized in January 2025 [15]. "Formerly approved, now compounded" is the accurate frame — not "never approved," and not "currently approved."
Sermorelin mechanism of action
Sermorelin mechanism of action begins at the GHRH receptor (GHRH-R), a class B G-protein-coupled receptor (a docking site that, when filled, fires a chemical signal inside the cell) on the pituitary's somatotrophs — the growth-hormone-producing cells [12]. Binding activates the Gs / adenylate cyclase / cAMP / protein kinase A pathway (cAMP is a fast internal messenger; PKA is the enzyme it switches on), which drives growth-hormone gene transcription and pulsatile release [12].
Because sermorelin acts upstream on the gland instead of supplying outside growth hormone, the normal brakes stay on: somatostatin (the opposing hormone that halts GH release) and IGF-1 (insulin-like growth factor 1, the liver-made messenger that carries out most of growth hormone's effects and also feeds back to limit it) keep the natural pulse pattern intact [12]. Downstream, raised growth hormone lifts hepatic IGF-1 — the research on sermorelin tracks this GH/IGF-1 axis as its main readout. An editorial argued that preserving this feedback-regulated pulse makes a secretagogue a more physiologic approach to adult growth-hormone insufficiency than recombinant growth hormone [4].
Sermorelin peptide: GHRH(1-29) in the literature
The sermorelin peptide is a single 29-residue chain, supplied as a lyophilized (freeze-dried) powder because peptides in solution degrade — a chemistry constraint that also explains why oral and sublingual "sermorelin" products are widely criticized as ineffective: the molecule is broken down in the gut, and even the intranasal route returned only ~3-5% bioavailability in pharmacokinetic work [3].
The published record on the peptide is unusually quotable. In growth-hormone-deficient children, once-daily subcutaneous GHRH(1-29) raised first-year height velocity from about 4.1 cm/year to roughly 7-8 cm/year, without excessive IGF-1 generation [1]. In healthy older men, 0.5 mg and 1 mg twice daily for 14 days produced dose-related rises in 24-hour growth hormone and IGF-1, and after the high dose those parameters no longer differed from young men, with no change in fasting glucose [2]. A 2025 Nature Reviews Endocrinology review synthesizes the biology of GHRH and its analogues across health and disease, from receptor signaling to therapeutic applications [12].
What sermorelin is and is not
Sermorelin is a research-grade GHRH analog with a substantial human literature, a short half-life, and a clear analytical fingerprint. It is not a banned or unsafe drug — it is simply no longer sold as a branded product. It is also not a weight-loss compound: body-composition evidence in the GHRH-analog class comes mostly from the related, stabilized analog tesamorelin, not from sermorelin-specific trials [6].
Two honest gaps anchor the rest of this digest. First, anti-aging and body-composition marketing outpaces the evidence; an Annals of Internal Medicine editorial judged growth-hormone-secretagogue use for aging "not yet ready for prime time" [5]. Second, GH and IGF-1 are mitogenic (growth-promoting), so chronically raising them carries a recognized theoretical oncologic concern for any GH-axis intervention [5]. This site is an evidence board, not a clinic — see the research on sermorelin, the doses studied in the literature, and anti-doping detection of GHRH analogs.