Growth Hormone Research Peptides

GHRH Analogs

CJC-1295 and Tesamorelin are modified, more stable versions of growth-hormone-releasing hormone, designed to resist the rapid enzymatic degradation that limits native GHRH(1-44). Tesamorelin in particular has a research base concentrated on lipid metabolism and visceral fat models, distinguishing it from more general GH-axis stimulation research. Sermorelin — a synthetic fragment corresponding to the first 29 amino acids of native GHRH, GHRH(1-29) — is the earlier, unmodified compound that CJC-1295 and Tesamorelin's stability modifications were built to improve on: it retains full GHRH receptor bioactivity but is cleared from circulation quickly, which is why later analogs were engineered for a longer half-life. See its full research profile.

Ghrelin-Receptor Secretagogues (GHRP)

Ipamorelin is a selective ghrelin-receptor agonist — a class commonly referred to as GHRP (growth-hormone-releasing peptides), even though several of the compounds in it are small, non-peptide molecules — studied for its ability to stimulate pulsatile GH release while showing minimal cross-reactivity with cortisol or prolactin pathways. This selectivity profile makes it a frequent reference compound in GH-axis research. Because GHRH analogs and GHRP secretagogues act on complementary points of the same axis, they are often studied together, as in the CJC-1295 + Ipamorelin blend, to examine combined pulsatile release patterns. Ipamorelin's selectivity was a deliberate improvement on the earliest GHRP compound, GHRP-6, which reliably releases GH but also triggers meaningful cortisol, ACTH, and prolactin elevation, and a pronounced appetite-stimulating effect that Ipamorelin was specifically engineered to avoid. See its full research profile.

Dual-Receptor & Cardioprotective Secretagogue Research

Hexarelin is also a ghrelin-receptor (GHSR1a) agonist, but unlike Ipamorelin it additionally binds CD36, a second receptor unrelated to GH release. This dual-receptor profile has pushed Hexarelin research in a different direction from the rest of this category: alongside GH-secretagogue pharmacology, a substantial share of its literature examines GH-independent cardioprotective effects mediated through CD36, including protection of cardiomyocytes from ischemia/reperfusion injury. See its full research profile.

GHRH vs GHRP: What's the Difference?

GHRH analogs and GHRP secretagogues both push growth hormone release upward, but through different receptors and mechanisms. GHRH analogs — Tesamorelin, CJC-1295, and Sermorelin — bind the GHRH receptor and extend or stabilize the body's own releasing signal, amplifying a natural pulse rather than creating a new one. GHRP compounds — Ipamorelin, Hexarelin, and the non-peptide Anamorelin — instead bind the ghrelin receptor (GHSR1a), triggering GH release independently of GHRH signaling. Because the two classes act on separate receptors along the same axis, they're frequently studied in combination (as with the CJC-1295 + Ipamorelin blend) to observe whether combining a GHRH analog with a GHRP produces a larger or more sustained pulse than either alone.

Clinical & Preclinical Trial Data

Tesamorelin: A Phase 3 randomized controlled trial (Falutz et al., New England Journal of Medicine, 2007; 412 HIV-infected adults with abdominal lipodystrophy) found that tesamorelin 2mg/day reduced visceral adipose tissue by 15.2% over 26 weeks, versus a 5.0% increase in the placebo group. A pooled analysis of two Phase 3 trials (806 participants total) confirmed a consistent 15–18% VAT reduction alongside triglyceride improvement. Based on this data, the FDA approved tesamorelin in November 2010 as Egrifta for VAT reduction in HIV-associated lipodystrophy — the only FDA-approved drug for this specific indication. See its full research profile or discovery history, or how it compares to CJC-1295.

Ipamorelin: The foundational pharmacology paper (Raun et al., European Journal of Endocrinology, 1998) characterized ipamorelin's activity in rat pituitary cells and pigs, not in a human trial — establishing its selectivity (no significant ACTH or cortisol elevation, unlike earlier ghrelin-receptor agonists) but not efficacy or safety in humans. No completed human clinical trial of ipamorelin has been located. See its full research profile, the CJC-1295 + Ipamorelin Blend research profile, or how Ipamorelin compares to CJC-1295.

CJC-1295: A human trial (Teichman et al., 2006; 65 healthy adult subjects) found that a single injection produced a dose-dependent GH increase of 2–10× baseline sustained for at least 6 days, and an IGF-1 increase of 1.5–3× baseline sustained for 9–11 days, consistent with an estimated half-life of 5.8–8.1 days. With repeated dosing, mean IGF-1 remained above baseline for up to 28 days, and the compound was well tolerated with no serious adverse events reported.

Hexarelin: Human GH-response data (Ghigo et al.) found that hexarelin's GH-releasing effect is strongly age- and pubertal-status-dependent: it produced a robust response in pubertal children and adults, but a substantially blunted response in prepubertal children and elderly subjects. In a separate comparison of 15 children and 4 adults with GH deficiency, hexarelin produced a GH response similar to or exceeding that seen with GHRH itself. Its cardioprotective research is entirely preclinical — a rat ischemia/reperfusion model found hexarelin improved cardiomyocyte survival and downregulated IL-1β signaling through cardiac GHSR1a receptors, independent of GH release. No completed human clinical trial for a specific therapeutic indication has been located; hexarelin is used mainly as a research and provocative-testing tool rather than an approved drug.

Sermorelin: Unlike most compounds on this page, sermorelin has a completed pediatric approval history. The pivotal trials supporting its FDA approval (as Geref, in a 110-patient trial of prepubertal children with idiopathic GH deficiency) found daily subcutaneous sermorelin increased height velocity from a baseline of 4.1 cm/year to 8.0 cm/year, with the effect sustained through 36 months of continuous therapy; 74% of treated children showed increased growth velocity after 6 months. Geref was FDA-approved in 1990 (with a further approval in 1997) and later discontinued from the market in 2008 — a 2013 FDA determination confirmed the withdrawal was for commercial reasons, not safety or effectiveness. Sermorelin is now available only through compounding pharmacies rather than as an FDA-approved commercial product.

GHRP-6: Originally characterized by Bowers and colleagues (Endocrinology, 1984), GHRP-6 has a decades-long human research record establishing it as a potent, reliably reproducible GH secretagogue, but one with a non-selective hormonal profile — meaningful cortisol, ACTH, and prolactin elevation alongside GH release, plus a pronounced appetite-stimulating effect not shared by later, more selective secretagogues. Its receptor-binding activity was also central to identifying the receptor class itself: GHRP-6 pharmacology guided the 1996 cloning of the growth hormone secretagogue receptor (GHS-R1a) by Howard and colleagues (Science), which in turn enabled the 1999 discovery of ghrelin by Kojima and colleagues (Nature) as that receptor's endogenous ligand. GHRP-6 is not FDA-approved and has not been developed into a marketed drug.

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Hexarelin, Sermorelin, and Anamorelin come up often in growth-hormone-axis research literature but aren't part of our standard catalogue. Hexarelin and Sermorelin can still be sourced for your order — get in touch for pricing and lead time. Anamorelin is included below for research context only; it isn't available from KYIN in any form.