Peptides Similar to GHRP-6
Compare GHRP-6 with related peptides and alternatives
📌TL;DR
- •4 similar peptides identified
- •GHRP-2: Very High - Same class of GHS peptides with similar mechanism
- •Ipamorelin: High - Both are GHS peptides activating GHS-R1a
Quick Comparison
| Peptide | Similarity | Key Differences |
|---|---|---|
| GHRP-6 (current) | - | - |
| GHRP-2 | Very High - Same class of GHS peptides with similar mechanism | GHRP-2 is more potent for GH release with less appetite stimulation; slightly different selectivity profile |
| Ipamorelin | High - Both are GHS peptides activating GHS-R1a | Ipamorelin is highly selective for GH release with minimal cortisol, prolactin, or appetite effects |
| Hexarelin | High - Related GHS hexapeptide with shared mechanism | Hexarelin is one of the most potent GHS peptides with notable cardiac effects |
| Sermorelin | Moderate - Both stimulate GH release but through different receptors | Sermorelin acts through GHRH receptor; GHRP-6 through GHS-R1a; synergistic when combined |
GHRP-2Very High - Same class of GHS peptides with similar mechanism
Differences
GHRP-2 is more potent for GH release with less appetite stimulation; slightly different selectivity profile
Advantages
GHRP-6 has more extensive research history; well-characterized pharmacology
Disadvantages
GHRP-6 has stronger appetite stimulation and cortisol/prolactin effects
IpamorelinHigh - Both are GHS peptides activating GHS-R1a
Differences
Ipamorelin is highly selective for GH release with minimal cortisol, prolactin, or appetite effects
Advantages
GHRP-6 has broader research base and higher potency per unit dose
Disadvantages
GHRP-6 has more off-target effects (cortisol, prolactin, appetite)
HexarelinHigh - Related GHS hexapeptide with shared mechanism
Differences
Hexarelin is one of the most potent GHS peptides with notable cardiac effects
Advantages
GHRP-6 has better-characterized dose-response in humans
Disadvantages
Hexarelin shows greater potency and additional cardiac benefits
SermorelinModerate - Both stimulate GH release but through different receptors
Differences
Sermorelin acts through GHRH receptor; GHRP-6 through GHS-R1a; synergistic when combined
Advantages
GHRP-6 is more potent and works through complementary mechanism
Disadvantages
Sermorelin is more physiological as a GHRH analog; FDA-approved (discontinued)
Compounds Related to GHRP-6#
GHRP-6 belongs to a family of growth hormone secretagogues (GHS) that includes both peptide and non-peptide compounds. Understanding the differences between these agents provides context for selecting the most appropriate research tool or therapeutic candidate.
GHRP-2 -- The More Potent Cousin#
GHRP-2 (D-Ala-D-betaNal-Ala-Trp-D-Phe-Lys-NH2) is a modified GHS hexapeptide considered to be the most potent peptide GH secretagogue developed. Compared to GHRP-6, GHRP-2 produces a greater GH response on a per-weight basis and has somewhat less pronounced appetite stimulation. GHRP-2 also shows less cortisol and prolactin co-release than GHRP-6 at equimolar doses, though both effects are still present. The improved profile of GHRP-2 was achieved through substitution of D-beta-naphthylalanine at position 2 instead of D-tryptophan.
Ipamorelin -- The Selective GHS#
Ipamorelin is a pentapeptide GHS that stands out for its high selectivity: it stimulates GH release with minimal effects on cortisol, prolactin, and appetite. This selectivity makes ipamorelin the "cleanest" GHS peptide in terms of GH-specific activity. However, the GH response to ipamorelin is somewhat lower than to GHRP-6 or GHRP-2 at comparable doses. Ipamorelin reached Phase 2 clinical trials for post-surgical GI recovery (ileus) before its development was discontinued.
Hexarelin -- The Cardiac GHS#
Hexarelin (His-D-2-methylTrp-Ala-Trp-D-Phe-Lys-NH2) is among the most potent GHS peptides and has attracted particular attention for its cardiovascular effects. Research has shown hexarelin has direct cardiac protective properties and can improve left ventricular function in patients with cardiac disease. Hexarelin's cardiac effects appear partly independent of GH release, potentially mediated through cardiac GHS receptors or CD36. However, hexarelin shows significant desensitization of GH response with repeated dosing, limiting its chronic use for GH stimulation.
Sermorelin -- The GHRH Analog#
Sermorelin (GRF 1-29) is a synthetic analog of the first 29 amino acids of GHRH. Unlike GHRP-6, it acts through the GHRH receptor rather than GHS-R1a. Sermorelin was FDA-approved for diagnostic testing and briefly for treatment of GH deficiency in children before being discontinued for commercial reasons. The combination of GHRP-6 with sermorelin produces synergistic GH release, making the two agents pharmacologically complementary.
MK-0677 (Ibutamoren) -- The Non-Peptide GHS#
MK-0677 is a non-peptide GHS-R1a agonist with oral bioavailability, developed by Merck. While sharing the same receptor target as GHRP-6, MK-0677 has key advantages: it can be taken orally, has a long half-life (approximately 6 hours), and produces sustained increases in GH and IGF-1 levels. MK-0677 has been studied in Phase 2/3 trials for sarcopenia and hip fracture recovery but has not received regulatory approval.
Comparative Summary#
| Feature | GHRP-6 | GHRP-2 | Ipamorelin | Hexarelin | Sermorelin |
|---|---|---|---|---|---|
| Receptor | GHS-R1a | GHS-R1a | GHS-R1a | GHS-R1a | GHRH-R |
| GH potency | High | Very high | Moderate | Very high | Moderate |
| Cortisol effect | Moderate | Mild | Minimal | Moderate | None |
| Prolactin effect | Moderate | Mild | Minimal | Moderate | None |
| Appetite stimulation | Strong | Moderate | Minimal | Moderate | None |
| Cardiac effects | Some | Minimal | Minimal | Significant | None |
| Desensitization | Partial | Partial | Minimal | Significant | Minimal |
| Route | SC/IV/IN | SC/IV | SC/IV | SC/IV | SC/IV |
| Half-life | ~20 min | ~25 min | ~2 hours | ~30 min | ~10-20 min |
Related Reading#
Frequently Asked Questions About GHRP-6
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