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GHRP-6

B

lead outcome

GH release

grades vary by outcome ↓

Peptide⚠ WADA-banned

also called — GHRP-6 · Growth Hormone Releasing Peptide-6 · sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂. INCI: none

GH secretagogue / ghrelin agonistappetite stimulation(research context)

Reference entry — not sold here. Historically the most important peptide in this class: the first GHRP, and the compound whose study led to the discovery of ghrelin. Not approved anywhere; the marketed anti-aging use is untested in humans. No dosing published here.

In brief

GHRP-6 is the original growth-hormone-releasing peptide (Bowers, 1984) — the compound from which the entire GH-secretagogue class descends, and whose study led to the discovery of the ghrelin receptor (1996) and ghrelin itself (1999). It reliably raises GH but is non-selective, producing the strongest appetite stimulation of any GHRP plus modest cortisol/prolactin. It is not approved anywhere, and the popular anti-aging / muscle use is untested in humans. Banned in sport.

Legal standing, by region

International

See note

- Everywhere — not approved for human therapeutic use; a research compound (503A Category-2 / gray-market). (Unlike GHRP-2, GHRP-6 has no approval anywhere.) - ⚠ Sport: WADA-prohibited at all times — Section S2.2 (GH secretagogues).

⚠ WADA-prohibited in sportSport: WADA-prohibited at all times — Section S2.2 (GH secretagogues).

Evidence, by outcome

How we grade →

An honest grade per outcome — drawn from the evidence, not any catalogue. Hype and undemonstrated marketing claims grade low.

OutcomeEvidence base · effectGrade

GH release

Real, foundational pharmacology

Extensive characterisation (Bowers 1984 onward) + human PK · Strong, dose-dependent GH pulse

B

Appetite stimulation (cachexia / wasting research)

A feature for cachexia, a drawback for GH/fat-loss goals; preclinical as a therapy

Preclinical + Phase 1 observations · Strongest of any GHRP

C

Anti-aging / body composition / muscle (the popular use)

Untested for these goals

None in humans · Not demonstrated

F

Safety

Strong hunger; raises cortisol (~15–20% transient) and prolactin; long-term unknown; WADA-banned

Research + PK data · Characterised (short-term)

—

Disclosure

Vallydia sells its own cosmetic serums, and some ingredients graded here belong to the same categories as those products. Grades are drawn from the published evidence by the method we publish, and applied to our own ingredients on the same terms — our copper-peptide serum is graded no more kindly than the peptides it competes with. We disclose the interest so you can weigh it.

Trade names shown here (for example Matrixyl, Argireline, Syn-Ake) are the property of their respective owners and are used only to identify the ingredient under discussion. Their appearance implies no affiliation with, or endorsement by, the proprietor.

Evidence changes

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Identity

a synthetic hexapeptide (6 amino acids, with two D-residues for protease resistance; < 40 aa → peptide), a ghrelin-receptor (GHS-R1a) agonist. Half-life ~2.5 h.

Development & history

GHRP-6 was the first growth-hormone-releasing peptide, synthesised and characterised by Cyril Y. Bowers at Tulane University in 1984 (Bowers, Momany, Reynolds, Hong). It emerged from systematic modification of met-enkephalin analogs — Bowers noticed some enkephalin derivatives had unexpected GH-releasing activity unrelated to opioid receptors. Every later GH secretagogue (GHRP-2, hexarelin, ipamorelin, the oral MK-677) descends from it.
The "fake key": GHRP-6 activated a receptor no one had identified. Characterising it led first to the cloning of the GH-secretagogue receptor (GHS-R1a) in 1996 (Howard et al.), and then — hunting for that receptor's natural ligand — to the discovery of ghrelin in 1999 (Kojima & Kangawa, Osaka), found surprisingly in the stomach. GHRP-6 thus opened up the entire ghrelin / gut-brain hunger-and-GH axis. Its strong appetite effect, first dismissed as a side effect, turned out to be the crucial clue (ghrelin signals both hunger and GH).

Mechanism (as proposed)

GHRP-6 binds GHS-R1a on two populations — pituitary somatotrophs (driving GH release via the Gq-PLC-calcium pathway) and hypothalamic arcuate-nucleus orexigenic neurons (driving hunger). The same receptor drives both GH and appetite, exactly as endogenous ghrelin does physiologically. Its non-selectivity comes from additional HPA-axis (cortisol) and prolactin activation, plus gastric-motility effects.

Chemical identifiers

Cross-reference identifiers for the authoritative external databases — not a recipe, and nothing about how to use it.

PubChem CID4345065

InChIKeyWZHKXNSOCOQYQX-UHFFFAOYSA-N

SMILESCC(C(=O)NC(CC1=CNC2=CC=CC=C21)C(=O)NC(CC3=CC=CC=C3)C(=O)NC(CCCCN)C(=O)N)NC(=O)C(CC4=CNC5=CC=CC=C54)NC(=O)C(CC6=CN=CN6)N

via PubChem exact-name match (GHRP-6) · high confidence

Sources — 3 cited

01Bowers CY, Momany FA, Reynolds GA, Hong A. (Characterisation of GHRP-6 — the first GHRP.) 1984.

02Howard AD, et al. (Cloning of the GH-secretagogue receptor, GHS-R.) Science, 1996.

03Kojima M, Kangawa K, et al. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999. (the endogenous ligand GHRP-6 pointed to)

Updated 2026-07-13

Grades reflect the published evidence, not our interest. No dosing, reconstitution, or administration is published for research compounds — that restraint is deliberate.

Related compounds

GHRP-2 (Pralmorelin)B

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