CJC-1295 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.
CJC-1295
CJC-1295 is a synthetic growth hormone-releasing hormone (GHRH) analog. It stimulates the pituitary gland to release growth hormone and is almost universally used in combination with a GHRP like Ipamorelin to produce a more physiological GH pulse.
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| CJC-1295 | Mod-GRF(1-29) | |
|---|---|---|
| Category | Performance & Growth Hormone | Performance & Growth Hormone |
| Also known as | CJC-1295 DAC, CJC-1295 without DAC (Mod GRF 1-29), Modified GRF 1-29 | Modified GRF(1-29), CJC-1295 without DAC, Tetrasubstituted GRF, Sermorelin analog |
| Evidence | Research-stage | Research-stage |
| Dosing range | 100mcg–300mcg mcg, once daily (Mod GRF) or twice weekly (DAC version) | 100mcg–200mcg mcg, 2–3x daily, co-administered with a GHRP (pre-sleep, pre-workout, and/or upon waking) |
| Administration | Subcutaneous injection (most common), Intramuscular injection | Subcutaneous injection, Intramuscular injection |
| Key side effects | Water retention (especially early in protocol), Tingling or numbness in extremities, Injection site redness, Flushing (transient, shortly after injection) | 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 | 2 references | 2 references |
Key differences
- Administration: CJC-1295 — Subcutaneous injection (most common), Intramuscular injection; Mod-GRF(1-29) — Subcutaneous injection, Intramuscular injection.
- Frequency: CJC-1295 is typically once daily (Mod GRF) or twice weekly (DAC version); Mod-GRF(1-29) is 2–3x daily, co-administered with a GHRP (pre-sleep, pre-workout, and/or upon waking).
How each works
CJC-1295
Studies have demonstrated that CJC-1295 significantly increases plasma GH and IGF-1 levels. The DAC (Drug Affinity Complex) version extends the half-life to approximately 6–8 days via albumin binding, while Mod GRF 1-29 has a much shorter half-life (~30 minutes) and is dosed more acutely. Research in adults with GH deficiency has shown improved body composition and metabolic markers.
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.