CJC-1295 vs MK-677 (Ibutamoren)
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 profileMK-677 (Ibutamoren)
Oral non-peptide growth hormone secretagogue that mimics ghrelin to stimulate GH and IGF-1 release without injection. Long half-life (~24 hours) enables once-daily oral dosing. Widely researched for body composition, sleep quality, and IGF-1 elevation.
Full profile| CJC-1295 | MK-677 (Ibutamoren) | |
|---|---|---|
| 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 | Ibutamoren, Nutrobal, MK677, L-163,191 |
| Evidence | Research-stage | Research-stage |
| Dosing range | 100mcg–300mcg mcg, once daily (Mod GRF) or twice weekly (DAC version) | 10mg–50mg mg, once daily oral |
| Administration | Subcutaneous injection (most common), Intramuscular injection | Oral (capsule/liquid) |
| Key side effects | Water retention (especially early in protocol), Tingling or numbness in extremities, Injection site redness, Flushing (transient, shortly after injection) | Water retention, Increased appetite, Elevated fasting glucose (long-term), Fatigue (initial, transient) |
| Cited sources | 2 references | 2 references |
Key differences
- Administration: CJC-1295 — Subcutaneous injection (most common), Intramuscular injection; MK-677 (Ibutamoren) — Oral (capsule/liquid).
- Dosing units differ: CJC-1295 is dosed in mcg, MK-677 (Ibutamoren) in mg — they operate at different scales.
- Frequency: CJC-1295 is typically once daily (Mod GRF) or twice weekly (DAC version); MK-677 (Ibutamoren) is once daily oral.
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.
MK-677 (Ibutamoren)
MK-677 binds the ghrelin receptor (GHS-R1a) to stimulate pulsatile GH release and increase circulating IGF-1. Unlike peptide GHRPs it survives oral administration. Clinical trials demonstrate significant increases in GH pulsatility and IGF-1 without suppression of the endogenous GH axis, though long-term use raises glucose metabolism concerns.
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.