GHRP-6

GHRP-6 (Growth Hormone-Releasing Peptide 6, development code SKF-110679) is a synthetic hexapeptide and peptide active ingredient from the group of growth hormone secretagogues. It acts as a synthetic agonist at the ghrelin receptor (GHS-R1a) and stimulates the pituitary gland and hypothalamus to release pulsatile endogenous growth hormone (GH). It is closely related to other GHRPs such as Ipamorelin or Hexarelin and is frequently discussed in the same context as the CJC-1295 / Ipamorelin stack.

How does GHRP-6 work?

GHRP-6 (sequence: His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) is a synthetic met-enkephalin analog without opioid activity. It mimics the hunger hormone ghrelin and binds primarily to the Growth Hormone Secretagogue Receptor 1a (GHS-R1a). This activation releases GH pulses from the pituitary gland and secondarily increases IGF-1. Additionally, GHRP-6 binds to the CD36 receptor, which mediates antiapoptotic and cardioprotective effects in preclinical models.

Synergy with GHRH

When GHRP-6 is administered together with a GHRH analog, the GH pulses are additive: GHRH opens the GH pulse, GHRP-6 amplifies amplitude and duration. In studies on hypothalamo-pituitary disconnection, however, the GHRP-6 effect was blocked - an indication that the primary site of action lies in the hypothalamus.

What is GHRP-6 being researched for?

• GH stimulation and metabolism: preclinical data on muscle mass, recovery, and lipolysis, without an approved indication.
• Appetite regulation: GHS-R1a activation has an orexigenic (hunger-increasing) effect - documented pharmacologically as a side effect.
• Cardioprotection: in animal models, GHRP-6 protected against doxorubicin-induced cardiac muscle damage and activated antiapoptotic signaling pathways.

What is the state of research?

The clinical data on GHRP-6 comes predominantly from small studies of the 1990s on the GH axis and covers pharmacodynamic aspects, but not efficacy in defined diseases. A 2024 published preclinical paper (Berlanga-Acosta et al., Front Pharmacol) describes cardioprotective effects and formulates the hypothesis of translation into oncological supportive therapy. There is no FDA or EMA approval for GHRP-6 as a pharmaceutical drug. The evidence thus corresponds to Level 2: pharmacologically investigated, but off-label and not approved for therapeutic routines.

Which side effects are relevant?

• Significantly increased appetite (direct GHS-R1a activation).
• Transient increase in cortisol and prolactin.
• Water retention, paresthesias (tingling, numbness) at higher doses.
• Theoretical risks from chronically elevated GH/IGF-1 levels (insulin resistance, joint complaints) - without controlled long-term data.

Compared to the more selective Ipamorelin, GHRP-6 shows stronger hunger and cortisol signals.

Is GHRP-6 allowed in sports?

No. GHRP-6, as a representative of GH-releasing peptides, is explicitly listed on the WADA Prohibited List (section S2.2.4) - prohibited both in-competition and out-of-competition. Anti-doping laboratories detect GHRP-6 metabolites in urine using nano-LC-HRMS (Semenistaya et al., 2015).

GHRP-6 compared to related peptides

• vs. Tesamorelin / CJC-1295 (GHRH analogs): GHRP-6 uses a separate receptor (GHS-R1a instead of GHRH-R) and can therefore be administered additively in the same protocol - for example in the CJC-1295 / Ipamorelin stack.
• vs. Ipamorelin: Ipamorelin is more selective at GHS-R1a and causes less hunger and cortisol increase.
• vs. Hexarelin: Hexarelin is a close relative with slightly stronger GH release, but also a pronounced orexigenic effect.

How is GHRP-6 dosed in studies (informational)?

In research literature, 100-300 µg per dose, subcutaneously, one to three times daily are frequently described - often distributed around training times and before sleep. This is an informal summary from clinical study protocols, not a dosing recommendation.

Current developments

Research interest in GHRP-6 has shifted since the 2010s from pure GH stimulation toward cardioprotective and cytoprotective applications. The 2024 Frontiers in Pharmacology paper (Berlanga-Acosta et al.) positions GHRP-6 as a potential candidate for the prevention of chemotherapy-induced cardiotoxicity - clinical translation is pending.

This article is for informational purposes only and does not replace medical advice. No recommendation for purchase or use. As of: 2024.