Hexarelin vs Mod-GRF(1-29)
A neutral, side-by-side comparison of two performance & growth hormone peptides — their mechanisms, dosing ranges, administration routes, side effects, and research evidence. For research and educational purposes only.
Hexarelin
Hexarelin is a potent synthetic hexapeptide GHRP (Growth Hormone-Releasing Peptide) that stimulates GH release via the ghrelin receptor. It produces among the highest GH pulses of any GHRP, but also elevates cortisol and prolactin — a trade-off that distinguishes it from more selective options like Ipamorelin.
Full profileMod-GRF(1-29)
Mod-GRF(1-29) is a stabilized analog of growth hormone-releasing hormone (GHRH) that spans residues 1–29 of the native peptide. Unlike CJC-1295 (which includes a Drug Affinity Complex for multi-day half-life), Mod-GRF(1-29) has a short ~30-minute active window — mimicking the natural GHRH pulse pattern. It is the preferred GHRH component for precise, pulsatile GH protocols when combined with a GHRP.
Full profile| Hexarelin | Mod-GRF(1-29) | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | Examorelin, EP 23905, MF-6003 | Modified GRF(1-29), CJC-1295 without DAC, Tetrasubstituted GRF, Sermorelin analog |
| Evidence | Preclinical only | Research-stage |
| Dosing range | 50mcg–200mcg mcg, 1–3x daily (cycling recommended to prevent desensitization) | 100mcg–200mcg mcg, 2–3x daily, co-administered with a GHRP (pre-sleep, pre-workout, and/or upon waking) |
| Administration | Subcutaneous injection, Intramuscular injection | Subcutaneous injection, Intramuscular injection |
| Key side effects | Cortisol elevation, Prolactin elevation, Water retention, Increased appetite | Water retention (mild, dose-dependent), Tingling / numbness in extremities (carpal tunnel-like at high doses), Increased appetite (via GHRP component — less with Mod-GRF alone), Flushing or warmth at injection site |
| Cited sources | 1 reference | 2 references |
Key differences
- Evidence level differs: Hexarelin is preclinical only, while Mod-GRF(1-29) is research-stage.
- Frequency: Hexarelin is typically 1–3x daily (cycling recommended to prevent desensitization); Mod-GRF(1-29) is 2–3x daily, co-administered with a GHRP (pre-sleep, pre-workout, and/or upon waking).
- Research depth: this profile cites 1 source for Hexarelin vs 2 for Mod-GRF(1-29).
How each works
Hexarelin
Hexarelin produces dose-dependent GH release significantly greater than GHRP-6 or Ipamorelin. It also has direct cardioprotective effects via CD36 receptor binding, independent of GH — making it unique among GHRPs. Studies show protection from ischemic cardiac injury and myocardial fibrosis reduction in animal models. Desensitization occurs with chronic continuous use.
Mod-GRF(1-29)
Native GHRH(1-29) is rapidly cleaved by plasma dipeptidyl peptidase IV (DPP-IV) within 2–3 minutes. Mod-GRF(1-29) incorporates four amino acid substitutions (positions 2, 8, 15, 27) that resist DPP-IV degradation, extending the half-life to approximately 30 minutes while preserving GHRH receptor binding affinity. This creates a half-life window aligned with physiological GH pulsatility, making it suitable for 2–3x daily injections that mimic natural GH release patterns.
This comparison aggregates public research and structured profile data for informational purposes only. It is not medical advice and does not recommend either compound for human use. Consult a qualified healthcare provider before considering any peptide.