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GH-axis

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GH-releasing hexapeptide (ghrelin agonist)

GHRP-6

Also known as: Growth Hormone Releasing Peptide 6, His-D-Trp-Ala-Trp-D-Phe-Lys-NH2, SK&F 110679

Older GH-releasing peptide that also stimulates appetite through the ghrelin receptor — a feature for some users, a side effect for others.

Reviewed 2026-05-04

What it does

GHRP-6 is one of the original synthetic growth-hormone-releasing peptides — a 6-amino-acid ghrelin-receptor agonist that reliably stimulates pulsatile GH release from the pituitary. Unlike its more selective successor ipamorelin, GHRP-6 also activates the appetite circuitry, producing meaningful hunger stimulation as a near-universal effect. Multiple human studies in the 1990s and 2000s characterized its GH-releasing pharmacology. Recreational community use has largely shifted to ipamorelin (cleaner side-effect profile) or MK-677 (oral, longer-acting).

Used for

Dose

Starting
100 mcg · 1–3× daily
Common
200 mcg · 1–3× daily
Upper
300 mcg · 1–3× daily
When
BedtimeGH secretagogue with strong appetite stimulation. Pre-bed dosing is the obvious pick — eating after a GHRP-6 dose collapses the GH response and worsens sleep latency.
Site
subcutaneous

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⚠ Caution

  • Active malignancy (theoretical concern from sustained GH/IGF-1 elevation)
  • Uncontrolled diabetes (insulin resistance worsening with GH spikes)
  • Pregnancy and breastfeeding
  • Adolescents with open growth plates (use only under endocrinology supervision)
  • Significant pre-existing appetite dysregulation (binge eating disorder, etc. — appetite stimulation is meaningful)
  • Known hypersensitivity to peptide formulations

Your stack

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Use this peptide

Reconstitution & storage

Lyophilized powder reconstituted with bacteriostatic water. A 5 mg vial in 2.5 mL BAC water = 2 mg/mL, making a 100 mcg dose = 5 units on a U-100 syringe. Use the Juno calculator to verify.

Storage. Lyophilized: refrigerate. Reconstituted: refrigerate 2–8 °C, use within 30 days.

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Monitoring & questions

Reported side effects
  • Significant appetite stimulation / hunger (the defining differentiator from ipamorelin)
  • Transient cortisol and prolactin elevation (more pronounced than with ipamorelin)
  • Water retention, mild puffiness
  • Lethargy or transient flushing post-injection
  • Numbness or tingling (rare; consistent with high-IGF-1 carpal-tunnel-like effects with chronic use)
  • Reduced glucose tolerance with sustained use
Biomarkers Juno tracks

Reference

How it works

Agonist at the growth hormone secretagogue receptor (GHSR-1a, the endogenous ghrelin receptor) at the anterior pituitary and hypothalamus. Drives pulsatile GH release synergistically with GHRH or GHRH analogs (CJC-1295). Substantial ghrelin-pathway activity in the hypothalamic appetite circuit produces hunger and may transiently elevate cortisol and prolactin more than ipamorelin does.

Juno's take

GHRP-6's clinically meaningful differentiator from ipamorelin is appetite stimulation — a feature in cachexia or chronic-illness contexts, a side effect for body-recomposition users. There's no published evidence that GHRP-6 outperforms ipamorelin on body-composition outcomes. Most modern users should default to ipamorelin unless appetite stimulation is a goal.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Stimulation of endogenous GH release

Tier 2high confidence

Multiple human pharmacology studies (Bowers 1990s, Camanni 1998, Massoud 1996) consistently demonstrate acute GH release after SubQ or IV administration in healthy adults and in older adults. The hormonal effect is well established. Tier 2 because the studies are smaller and the indication is biochemical, not a clinical outcome.

Bowers CY et al. 1984Massoud AF et al. 1996

Appetite stimulation / cachexia adjunct

Tier 2high confidence

Ghrelin-receptor activation drives appetite — multiple human studies show acute hunger increase after GHRP-6 administration. Mechanistic work supports use in cachexia/anorexia of aging, though large clinical-outcome trials in cachexia have not been completed for GHRP-6 specifically (most cachexia work has moved to anamorelin and other newer ghrelin agonists).

Camanni F et al. 1998

Body composition / fat loss / muscle gain

Tier 3high confidence

Recreational use is widespread but not directly studied at clinical-outcome level. Generalizing from acute GH release to sustained body-composition change is mechanism-as-evidence, which Skill Rule 3 cautions against.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Sleep quality

Tier 3medium confidence

Plausible mechanism via GH/ghrelin sleep effects. No well-designed RCT with sleep as primary endpoint specifically for GHRP-6.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Citations (3)
  1. [1]
    On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone
    Bowers CY, Momany FA, Reynolds GA, Hong A. · Endocrinology · 1984 · PMID 2156869
    Foundational pharmacology citation for GHRP-6 as a GH secretagogue.
    View source
  2. [2]
    The effect of repeated administration of hexarelin, a growth hormone releasing peptide, and growth hormone releasing hormone on growth hormone responsiveness
    Massoud AF, Hindmarsh PC, Brook CG. · Clinical Endocrinology · 1996 · PMID 8772586
    Anchor for human GH-release pharmacology of GHRP-class peptides; characterizes saturation and tachyphylaxis.
    View source
  3. [3]
    Growth hormone-releasing peptides and their analogs
    Camanni F, Ghigo E, Arvat E. · Frontiers in Neuroendocrinology · 1998 · PMID 9710238
    Cross-indication review supporting Tier 2 GH-release and appetite-stimulation framing across the GHRP class.
    View source