GHRP-6

Overview.

GHRP-6 has never been approved as a drug anywhere and is sold only as an unapproved research chemical. It is one of the original synthetic ghrelin-receptor-agonist hexapeptides, discovered in the 1980s as part of a met-enkephalin-derived GH-releasing peptide series, and is notable among GHRPs for pronounced appetite (ghrelin-like) stimulation alongside GH release.

Also known as SKF-110679 · His-DTrp-Ala-Trp-DPhe-Lys-NH2

The molecule, decoded.

Sequence: His-D-Trp-Ala-Trp-D-Phe-Lys-NH2
Length: 6 residues
Molecular weight: 873 g/mol
Formula: C46H56N12O6
CAS number: 87616-84-0 (free base); 145177-42-0 (acetate salt)
Half-life: ~2.5 hours (after IV dosing)
Routes studied: oral (poor bioavailability, <1%), subcutaneous (unapproved research-chemical use)
Modifications: D-Trp and D-Phe residues; C-terminal amide

How it works.

Agonizes the ghrelin receptor (GHS-R1a), a G-protein-coupled receptor structurally and functionally unrelated to the GHRH receptor, triggering GH release from pituitary somatotrophs together with marked appetite stimulation and lesser cortisol/prolactin elevation.

Evidence · Early or small human studies

What the research shows

small RCT1992

In a single-blind, randomized, placebo-controlled study in 10 healthy men, oral GHRP-6 raised GH in a dose-dependent way, but the highest oral dose gave a GH response only comparable to an IV dose 300 times smaller, implying very low oral potency.

10 healthy men

Source

small PK study2013

After single IV injections in 9 healthy men, GHRP-6 showed bi-exponential kinetics with a distribution half-life of 7.6 min and an elimination half-life of 2.5 ± 1.1 h.

9 healthy men

Source

review2017

A class-wide review of GH secretagogues found insufficient long-term safety data and a recurring glucose/insulin-sensitivity signal across the GHRP/GHRH class.

mixed adult populations

Source

discovery research1984

GHRP-6 was developed in the 1980s as a synthetic met-enkephalin-derived analogue selected for growth-hormone-releasing activity, distinct in mechanism from GHRH-based approaches.

n/a

What to know first.

Based on: small human pharmacology/PK studies (e.g., oral GHRP-6 in 10 men, 1992; IV PK in 9 men, 2013) plus an FDA safety review; no controlled efficacy or chronic-use safety trials.

Reported side effects

pronounced appetite stimulation
cortisol elevation
increase in blood glucose (per FDA safety review)

Cautions

FDA-cited effect on cortisol and blood glucose
no chronic human safety data
not evaluated in a formal registration trial program

Checked 2026-09

Where it stands.

Not FDA-approved · not available for sale or prescription. GHRP-6 is not FDA-approved and is not available for sale or prescription. We profile it because people ask about it.

FDA: Not approved; no company has taken GHRP-6 through a registration trial program.
Compounding: GHRP-6 was placed in Category 2 under FDA's 503B (outsourcing facility) interim policy only on September 29, 2023, citing immunogenicity risk and effects on cortisol and on blood glucose (decreased insulin sensitivity); it remains there as of FDA's April 22, 2026 update. Under 503A it has never been in Category 2: FDA lists it in 503A Category 3 ('nominated without adequate support', updated May 14, 2026), and it is not eligible for 503A compounding.
Sport (WADA): Prohibited at all times under S2 (GH-releasing peptides / GHRPs) of the WADA Prohibited List, naming GHRP-6 explicitly.
Enforcement: FDA 503B Category 2 listing, Sept 29, 2023, still in effect per fda.gov (updated Apr 22, 2026); 503A status is Category 3 (nominated without adequate support)
FDA warning letter to Tailor Made Compounding (Apr 1, 2020) cited compounding with GHRP-6 among peptides not eligible under 503A

References (4)

Overview.

The molecule, decoded.

How it works.

What the research shows

What to know first.

Reported side effects

Cautions

Where it stands.

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