GHRP-6

GHRP-6 (Growth hormone-releasing peptide-6; also known as SKF-110679) is a modified peptide studied for its effects on growth hormone. Synthetic hexapeptide ghrelin-receptor agonist that raises growth hormone and appetite. Not approved for any medical use; banned by WADA.

Growth hormone-releasing peptide-6 (GHRP-6) is a synthetic hexapeptide (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) that acts as an agonist of the ghrelin receptor, also called the growth hormone secretagogue receptor (GHS-R1a). It was developed from synthetic met-enkephalin analogues under the code SKF-110679 and is structurally unrelated to growth hormone-releasing hormone (GHRH). By mimicking ghrelin, it stimulates the pituitary gland to release growth hormone (GH) and acts synergistically with GHRH.

Overview

In a 1990 study of 18 healthy men, intravenous doses of 0.1 to 1.0 mcg/kg raised GH without adverse clinical effects or laboratory abnormalities.

Like ghrelin, it also stimulates appetite, and it is less selective than ipamorelin: small rises in cortisol and prolactin have been reported.

Its oral bioavailability is below 1 percent, so it is given by injection, and carbohydrate or fat intake blunts the GH response.

GHRP-6 is not approved for any medical use; it is sold as a research chemical and self-administered for muscle gain, recovery and appetite.

As a growth hormone-releasing peptide, it is prohibited by WADA under category S2 (peptide hormones, growth factors, related substances and mimetics), banned both in and out of competition.

Mechanism of action

Stimulates the pituitary to release growth hormone by mimicking ghrelin at its receptor. Also increases appetite. May slightly raise cortisol and prolactin. Given by subcutaneous injection.

Reported effects

Effects reported in the literature and from preclinical models include:

• In human studies, growth hormone-releasing peptides such as GHRP-6 released growth hormone more reproducibly than growth hormone-releasing hormone. ^[1] Phase I
• Across different metabolic states, the growth hormone response to GHRP-6 was less impaired than the response to growth hormone-releasing hormone. ^[1] Phase I
• Intravenous GHRP-6 gave a lower growth hormone response in patients with growth hormone deficiency than in normal children, though individual results overlapped considerably. ^[2] Phase I
• The growth hormone response to GHRP-6 was almost completely blocked in patients with pituitary stalk transection, suggesting a low-cost diagnostic test for that condition. ^[2] Phase I
• GHRP-6 acted as a powerful growth hormone releaser in obese subjects. ^[3] Phase I
• In experimental animal models, GHRP-6 released growth hormone independently of the hypothalamic factors growth hormone-releasing hormone and somatostatin. ^[3] Preclinical

Evidence grades: FDA approvedApproved (non-US)Phase IIIPhase IIPhase IPreclinicalAnecdotal

Dosage and administration

Human research dose

• 0.1-1.0 mcg/kg as a single intravenous bolus (1990 study in healthy men)

Reported non

• clinical use: about 100 mcg (roughly 1 mcg/kg) subcutaneously, 2-3 times daily

Timing

• on an empty stomach, since carbohydrate or fat intake blunts the growth hormone response

Natty status

GHRP-6 is classified as not natty. It appears on the WADA prohibited list and is banned by major natural bodybuilding federations.^[4] Use of this compound places the athlete in the enhanced category rather than the natural category in competitive contexts.

Research

The peptide has been the subject of 6 studies and reference works collected on this site. Additional bibliography is in § External links below.

Related compounds

Other peptides in this catalogue with overlapping mechanisms or status:

Frequently asked questions

What is GHRP-6?

Synthetic hexapeptide ghrelin-receptor agonist that raises growth hormone and appetite. Not approved for any medical use; banned by WADA.

What is GHRP-6 used for?

GHRP-6 (Growth hormone-releasing peptide-6) is used to raise growth hormone levels for muscle gain and recovery, and to increase appetite. In a 1990 study of 18 healthy men, doses injected into a vein raised growth hormone with no harmful effects found.

How does GHRP-6 work?

A lab-made chain of six amino acids that copies ghrelin, the body's hunger hormone, at its receptor. This signals the pituitary gland at the base of the brain to release growth hormone, and can also slightly raise the stress hormone cortisol and the hormone prolactin. It is given by injection under the skin, because less than 1 percent is absorbed when swallowed.

Is GHRP-6 natty?

No. GHRP-6 is classified as not natty. It is prohibited by WADA and banned by most natural bodybuilding federations. Use places an athlete in the enhanced category.

Is GHRP-6 banned by WADA?

Yes. GHRP-6 is prohibited by the World Anti-Doping Agency (WADA), so drug-tested athletes cannot use it. Check the current WADA Prohibited List before competing.

How is GHRP-6 administered?

GHRP-6 is typically administered via: subcutaneous injection. Dosage and administration protocols vary; see the Dosage section for details.

References

1. ^ a b Evaluation of pituitary GH reserve with GHRP-6. Review
2. ^ a b Growth hormone releasing hexapeptide-6 (GHRP-6) test in the diagnosis of GH-deficiency. Review
3. ^ a b Regulation of growth hormone secretion by the growth hormone releasing hexapeptide (GHRP-6). Review
4. ^ a b World Anti-Doping Agency. (2026). Prohibited List 2026.

External links

• The emerging landscape of performance-enhancing peptides modulating GH-IGF1 axis: bridging the gap between clinical evidence and patient self-administration.
• Assessing the role of ghrelin and the enzyme ghrelin O-acyltransferase (GOAT) system in food reward, food motivation, and binge eating behavior.
• Wikipedia article
• 10mg GHRP-6 — commercial