Sermorelin is the GHRH(1-29) fragment studied for pulsatile growth-hormone release.

The short version

Sermorelin is a small peptide — a chain of 29 amino acids — that copies the front end of GHRH (the brain's own "make growth hormone" signal). It tells the pituitary gland to release the body's own growth hormone (GH) in natural bursts, rather than injecting GH from outside. That GH then raises IGF-1 (a growth signal the liver makes when GH rises). It was once an approved children's medicine, was pulled from the US market in 2008 for business reasons, and is now made by compounding pharmacies. This site reads the published studies plainly and cites each one.

What the sermorelin literature establishes

Sermorelin (sermorelin acetate) is a synthetic, amidated 29-amino-acid peptide that reproduces the amino-terminal 1-29 fragment of human growth hormone-releasing hormone (GHRH). It is the shortest fragment of GHRH that retains full activity at the GHRH receptor ^[1], which is the single fact the rest of this site turns on: the minimal sequence that still does the whole job.

Functionally, sermorelin is a secretagogue — something that tells a gland to release its own hormone. It binds GHRH receptors on the growth-hormone-producing cells of the anterior pituitary (somatotrophs) and prompts them to synthesize and release the body's own growth hormone in natural pulses ^[13]. Because it acts upstream — on the gland rather than supplying hormone from outside — the body's feedback brakes (somatostatin and IGF-1) stay intact, so the pulsatile pattern of GH is preserved ^[4].

The clinical record is unusually substantial for a research peptide. In a multicenter trial of growth-hormone-deficient children, once-daily subcutaneous GHRH(1-29) accelerated 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 increases in 24-hour GH and IGF-1; after the high dose, their GH/IGF-1 parameters no longer differed from those of young men ^[2]. Pharmacokinetic work in 30 healthy men found measurable GH release from intravenous doses as low as 0.25 mcg/kg, with GH staying elevated for roughly 3 hours despite rapid clearance ^[3]. Those are the load-bearing studies; the research page works through each.

The honest counterweight is equally a finding. An Annals of Internal Medicine editorial judged the use of growth-hormone secretagogues to prevent or treat aging "not yet ready for prime time" ^[5] — and the adult anti-aging and body-composition claims that fill the popular record run well ahead of the sermorelin-specific evidence. This monograph keeps the two apart.

Sermorelin acetate: identity and structure

Sermorelin acetate is the acetate salt of the amidated GHRH(1-29) peptide. Its molecular weight is 3357.9 Da, its molecular formula is C149H246N44O42S, and its CAS number is 86168-78-7 (114466-38-5 for the acetate). It carries an amide group at the C-terminus, which protects the active fragment from one route of enzymatic breakdown.

The "1-29" in the name is the whole point of the identity. Endogenous human GHRH is 44 amino acids long, but only the first 29 are required for full receptor activity ^[1]. Sermorelin is therefore the minimal essential sequence — a design that mirrors what is, structurally, the same idea: the smallest piece that still binds the GHRH receptor and triggers GH release. That structural compactness is also why the native peptide is short-lived in plasma, which in turn motivated the longer-acting analogs discussed on the comparison pages.

Sermorelin peptide: a GHRH-analog classification

Classified as a sermorelin peptide, the molecule sits in the GHRH-analog family of growth-hormone secretagogues — distinct from the growth-hormone-releasing peptides (GHRPs) such as ipamorelin, which act on a different receptor entirely. A GHRH analog works through the GHRH receptor (GHRH-R, a class B G-protein-coupled receptor); a GHRP works through the ghrelin/GHS receptor. Both raise GH, but by different doors into the same somatotropic axis ^[14].

This distinction matters for anyone comparing compounds. Sermorelin's claim to attention is that it is the native fragment — it does not introduce a foreign mechanism, it amplifies the existing GHRH signal. The trade-off is its brevity: a plasma half-life on the order of 10-12 minutes after intravenous administration ^[3]. The sermorelin half-life and pharmacokinetics section covers what that brevity means for how the peptide was dosed in studies, and sermorelin vs ipamorelin sets the two receptor classes side by side.

Sermorelin benefits: what the GHRH(1-29) research actually shows

The defensible sermorelin benefits, stated against the evidence, are narrow and specific. In its historical pediatric use, GHRH(1-29) accelerated linear growth in GH-deficient children ^[1]. In aging research, it raised GH and IGF-1 in older men toward youthful levels over 14 days, without changing fasting glucose ^[2]. A related GHRH-analog cognition trial reported a favorable effect on cognition in older adults alongside a 117% rise in IGF-1 ^[6]. An editorial argued that, as a physiologic secretagogue preserving pulsatile release and feedback, sermorelin may be a more physiologic approach to adult-onset GH insufficiency than recombinant GH ^[4].

What the research does not establish is equally important. There are no controlled sermorelin weight-loss trials, and the body-composition signal in the literature comes mostly from the stabilized analog tesamorelin and from general GH-axis biology, not from sermorelin itself ^[5][6]. The recognized safety caveat is that chronically raising GH and the mitogenic mediator IGF-1 is theorized to carry oncologic risk — a consideration for any GH-axis intervention. Sermorelin is also prohibited in sport (WADA category S2) ^[8]. Read benefits through that frame: the research page separates what was measured from what is marketed.