Research brief / GHRH(1-29)
Sermorelin is the GHRH(1-29) fragment, read here through what the studies actually measured.
A 29-amino-acid pituitary signal that tells the body to release its own growth hormone. The mechanism, the trial numbers, and the honest gaps — sourced line by line.
The short version
Sermorelin is a lab-made copy of the first 29 amino acids of GHRH (growth hormone-releasing hormone — the brain's own 'make growth hormone' signal). Instead of supplying growth hormone directly, it tells the pituitary gland to release its own, in the natural bursts the body normally uses. In growth-hormone-deficient children it roughly doubled first-year growth speed [1]. In older men, two weeks of it pushed growth-hormone and IGF-1 (a growth signal the liver makes when GH rises) back toward young-adult levels [2]. This page is a plain digest of that research — not a product, and not dosing advice.
What sermorelin is
Sermorelin is GHRH(1-29)NH2, also written GRF(1-29) — the amidated 1-29 N-terminal fragment of the 44-amino-acid human growth hormone-releasing hormone, and the shortest fragment that keeps full activity at the GHRH receptor. Its molecular weight is roughly 3,358 Da; CAS 86168-78-7. It is a pituitary GH secretagogue (secretagogue: something that tells a gland to release its hormone) — it acts upstream, on the pituitary, rather than supplying growth hormone from outside.
That upstream position is the whole point. Because the body still controls the release through its own brakes — somatostatin and IGF-1 feedback — sermorelin supports pulsatile GH secretion (GH released in natural bursts, not a steady drip) instead of overriding it [11]. An editorial framed this preserved-feedback profile as a more physiologic approach to adult-onset GH insufficiency than supplying recombinant growth hormone directly [4].
The research record spans both clear wins and honest gaps. The strongest data sit in pediatric growth-hormone deficiency and short-term adult GH/IGF-1 studies; the weakest sit exactly where the marketing is loudest — long-term adult anti-aging use, where rigorous evidence is limited [5].
What the literature has actually shown
In prepubertal growth-hormone-deficient children, once-daily subcutaneous GHRH(1-29) accelerated linear growth: first-year height velocity rose from about 4.1 cm/year to roughly 7-8 cm/year, without excessive IGF-1 generation [1]. In healthy older men (mean age 68), subcutaneous GHRH(1-29) at 0.5 mg and 1 mg twice daily for 14 days produced dose-related increases in 24-hour GH and IGF-1; after high-dose treatment their GH/IGF-1 parameters no longer differed from those of young men, with no change in fasting glucose [2].
The pharmacology is fast and clean. In 30 healthy men, intravenous GHRH(1-29)NH2 elicited GH release at doses as low as 0.25 mcg/kg, with maximal release at 1-2 mcg/kg; despite rapid clearance, serum GH stayed elevated for about 3 hours [3]. Intranasal bioavailability was only 3-5% [3] — which is why the route that works in studies is injection, and why oral or sublingual 'sermorelin' products are widely criticized as ineffective.
A 2025 Nature Reviews Endocrinology review synthesized the biology of GHRH and its analogues across health and disease, covering receptor signaling, the GH/IGF-1 axis, and therapeutic applications [14] — useful context for reading any single sermorelin finding in proportion.
Sermorelin as a research peptide
Described as a sermorelin peptide, GHRH(1-29) is a 29-residue synthetic peptide supplied to laboratories as a lyophilized (freeze-dried) powder, because aqueous peptide solutions degrade [13]. Research-grade sermorelin is laboratory material — not a compounded prescription and not a finished medicine — so everything on this site is study-attributed and carries no human dosing instruction.
Its mechanism makes it a frequently-used reference compound in the GH-axis literature: it is the native, short-lived GHRH agonist against which longer-acting analogs are measured. The brevity of the native peptide — a plasma half-life on the order of 10-12 minutes [3] — is exactly what motivated the D-Ala2 substitution and DAC technology behind sermorelin vs CJC-1295 comparisons, and the stabilization behind tesamorelin. For the receptor pathway, dose-response data, and route considerations, see how sermorelin works and the research doses of sermorelin.
Sermorelin acetate
Sermorelin acetate is the amidated acetate salt of GHRH(1-29) — the form in which the peptide is typically supplied and studied (acetate-salt CAS 114466-38-5). The acetate counter-ion improves handling and stability of the lyophilized powder; the active moiety is unchanged GHRH(1-29)NH2. Regulatory note, stated precisely because it is commonly misreported: sermorelin was a formerly FDA-approved prescription drug (NDA 020443) for evaluation and treatment of growth-hormone deficiency / short stature in children, and was withdrawn from the US market in 2008 for commercial reasons — not for safety or efficacy [4]. It is now prepared by compounding pharmacies and treated as a long-standing Category-1 bulk drug substance under FDA's Section 503A framework. The full regulatory picture is on the frequently asked questions about sermorelin page.
The regulatory status, stated correctly
Sermorelin's regulatory history is one of the most consistently misreported things about it, so it is worth stating plainly. It is not 'never approved,' and it is not 'currently FDA-approved.' It was an FDA-approved prescription drug (NDA 020443) for evaluation and treatment of growth-hormone deficiency / short stature in children, and it was withdrawn from the US market in 2008 for commercial reasons — not because of any safety or efficacy problem [4]. After that withdrawal it became a compounded preparation, treated as a long-standing Category-1 bulk drug substance under FDA's Section 503A framework. The accurate one-line description is therefore 'a formerly FDA-approved GHRH analogue, now compounded.' It is not a controlled substance. This site reports that status as historical and regulatory fact and does not present sermorelin as a medicine to obtain or self-administer.
How to read this site
Three destinations carry the load. The sermorelin side effects page is the tolerability readout — injection-site reactions, reversible GHRH antibodies, the glucose-tolerance caveat in the elderly, and the WADA-prohibited and theoretical-oncologic notes; it is also where the question is sermorelin safe is answered as the two questions it really is. The research page covers mechanism, the human trials, sermorelin and the GH/IGF-1 axis, and the comparisons to tesamorelin, CJC-1295, ipamorelin, and direct GH. The research doses of sermorelin page is research-context only — what was administered, to which species, by which route, never a recommendation.
Every quantitative claim here — every dose, half-life, percentage, and effect size — resolves to a numbered citation in the sermorelin study references. Where the data is precise, this site is precise. Where it is thin, this site says so.