GHRP-1

Growth hormone-releasing peptide-1, GHRP1

Growth hormone axis

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Summary

Class: Synthetic heptapeptide (7 amino acids) growth hormone secretagogue; ghrelin receptor (GHS-R1a) agonist of the GHRP family
Mechanism: Mimics ghrelin at the pituitary and hypothalamus to release a pulse of growth hormone, with the GHRP-6-type side effects on appetite, cortisol and prolactin
Routes studied: Intravenous and intranasal in small human studies; intravenous and in vitro in animals; subcutaneous (community, rare)
Dose range reported: Early human pharmacology used single IV doses of roughly 1 µg/kg and higher intranasal doses †. Community reports are sparse; where they exist they borrow GHRP-6-style dosing (100–300 µg subcutaneous). No approved human dose
Half-life: Not well published; likely short (well under an hour), in line with GHRP-6 and GHRP-2
Storage: Lyophilised: refrigerate, protect from light. Reconstituted: refrigerate, use within ~4 weeks (community practice)
Regulatory status: Never approved; development abandoned

Doses are as reported in studies or by the community — never recommendations.

1What it is

GHRP-1 belongs to the first family of synthetic growth hormone releasing peptides developed by Cyril Bowers and colleagues from the late 1970s onward, starting from enkephalin-derived sequences that unexpectedly released GH. GHRP-6 came first and became the reference compound. GHRP-1 was a follow-on heptapeptide — GHRP-6 with a modified aromatic residue and an extra N-terminal alanine — designed for greater potency. It was investigated clinically in the early 1990s in partnership with Wyeth-Ayerst, but was overtaken by GHRP-2 (which became pralmorelin, an approved diagnostic in Japan) and by hexarelin, and was dropped.

Historically it matters because work on GHRP-1 and GHRP-6 led to the discovery of the ghrelin receptor and then of ghrelin itself. As a research compound today it is a minor player: the literature is thin, and most of what is said about it is extrapolated from GHRP-6 and GHRP-2. This profile is correspondingly short.

2How it's thought to work

All GHRPs act on the receptor that was later named , the ghrelin receptor, found on pituitary somatotrophs and in the hypothalamus. Activation releases GH directly from the pituitary and also stimulates hypothalamic GHRH release while opposing somatostatin, which is why GHRPs synergise with GHRH. Because the receptor is also present in the hypothalamic feeding circuits and on corticotroph-regulating neurons, GHRP-1, like GHRP-6, is expected to increase appetite and produce small rises in ACTH, cortisol and prolactin.

A synthetic peptide at the ghrelin receptor, producing a pulse of growth hormone that rides on top of the body's own rhythm rather than replacing it.Schematic — not to scale

3What the research shows

GH release in humans

Small studies in healthy volunteers in the early 1990s reported dose-dependent GH release after intravenous GHRP-1, with activity also demonstrated by the intranasal route, and the typical GHRP pattern of a brisk peak within 15–30 minutes (Bowers 1993 review, J Pediatr Endocrinol; Bowers 1998 review, Cell Mol Life Sci). Primary reports are few, old, and some appeared only in abstract form; treat specific numbers with caution. [1][2]

Graded C/D

Receptor pharmacology

Rat pituitary cell studies place GHRP-1 among the active GHRPs that signal via the phospholipase C / protein kinase C pathway, distinct from GHRH's cyclic AMP pathway, and show synergy when both are present (Cheng 1989, Endocrinology — GHRP-6 as the model compound; Bowers reviews for the series). [3]

Body composition, growth, recovery

No studies. Any community claim rests on the GHRP class.

4Reported side effects and interactions

Literature-reported

flushing and transient warmth after IV dosing; small, short-lived rises in cortisol and prolactin consistent with the class. No long-term human data.

Community-reported

very few reports; those that exist describe GHRP-6-like hunger, flushing and lethargy.

Theoretical. class concerns of GH — raised IGF-1 with repeated use, reduced insulin sensitivity, fluid retention, caution with active malignancy. Appetite stimulation is predictable.

Interactions. additive or synergistic with GHRH analogues (sermorelin, mod GRF 1-29, CJC-1295); glucose-lowering medicines may need adjusting if IGF-1 rises.

Markers researchers commonly monitor

Based on GHRP class physiology:

Marker	Why it's watched
IGF-1	the integrated marker of GH release with repeated use.
Fasting glucose, insulin, HbA1c	GH reduces insulin sensitivity.
Morning cortisol and prolactin	GHRP-1 is expected to raise both slightly; a baseline shows how much.
Body weight and appetite log	hunger is the most predictable effect.
Blood pressure	fluid retention is a class effect.
CBC and CMP	general baseline given the lack of long-term safety data.

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

Rarely offered; where it is, vials are typically 5 mg. with , swirl gently.

Open in calculator, pre-loaded →

6Commonly studied alongside

GHRP-6 and GHRP-2 (its siblings, with far more data), hexarelin, GHRH analogues (sermorelin, mod GRF 1-29, CJC-1295) for the synergy effect.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	Not FDA-approved. GHRP-2 and GHRP-6 are named in the FDA's 2023 Category 2 compounding list; GHRP-1 is not named explicitly †
European Union	Not authorised
United Kingdom	Not licensed
Australia	Not approved
South Africa	Not registered
Sport	Prohibited by WADA (S2 — GHRP-1 is named as an example of a GH-releasing peptide)

8Open questions

Essentially all of them: human pharmacokinetics, repeated-dose effects and safety were never properly published.
Whether GHRP-1 offers anything over GHRP-2 or ipamorelin; the historical answer from drug developers was no.

9References

1Bowers CY (1993). GH releasing peptides — structure and kinetics. J Pediatr Endocrinol. PubMed · DOI
2Bowers CY (1998). Growth hormone-releasing peptide (GHRP). Cell Mol Life Sci. PubMed · DOI
3Cheng K et al. (1989). The synergistic effects of His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 on growth hormone (GH)-releasing factor-stimulated GH release and intracellular adenosine 3',5'-monophosphate accumulation in rat primary pituitary cell culture. Endocrinology. PubMed · DOI
4Bowers CY et al. (1990). Growth hormone (GH)-releasing peptide stimulates GH release in normal men and acts synergistically with GH-releasing hormone. J Clin Endocrinol Metab. PubMed · DOI
5Smith RG et al. (1997). Peptidomimetic regulation of growth hormone secretion. Endocr Rev. PubMed · DOI

† Being confirmed by our reviewers against current sources.

10Community

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Self-reported side effects Phase 2

Not enough data yet. 0 of the 50 members needed have logged this compound for 4+ weeks. We don't show anything below 50, so no one can be identified.

11Page history

26 Oct 2026Profile published — awaiting medical review

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