Source comparison
MK-677 vs GHRP-2, CJC-1295, and Exogenous Growth Hormone
MK-677 (ibutamoren) Ghrelin receptor agonist Oral, once daily 60–90% at 25mg Preserves natural pulses Marked increase (dose-dependent) Oral convenience with sustained IGF-1 elevation; appetite management is critical GHRP-2 GH secretagogue peptide Subcutaneous
This comparison does not assign a generated winner or score.
- MK-677 (ibutamoren)
- Ghrelin receptor agonist
- Oral, once daily
- 60–90% at 25mg
- Preserves natural pulses
- Marked increase (dose-dependent)
- Oral convenience with sustained IGF-1 elevation; appetite management is critical
- GHRP-2
- GH secretagogue peptide
- Subcutaneous injection, 2–3x daily
- 40–60% (transient spikes)
- Amplifies pulse amplitude
- Moderate increase post-injection
- Requires injection discipline; shorter half-life limits sustained IGF-1
- CJC-1295 (DAC)
- GHRH analog
- Subcutaneous injection, weekly
- 50–80% (sustained)
- Blunts pulsatility slightly
- Minimal
- Long half-life; blunted GH pulses reduce peak amplitude
- Exogenous GH (somatropin)
- Direct GH replacement
- Subcutaneous injection, daily
- 100–200%+
- Suppresses endogenous pulses
- Variable (indirect via IGF-1)
- Highest IGF-1 ceiling; suppresses natural GH axis; expensive
- MK-677's primary advantage is oral bioavailability and once-daily dosing. Peptides like GHRP-2 require multiple daily injections to maintain elevated GH/IGF-1 because their half-lives are measured in minutes to hours, not the 24+ hour half-life of MK-677. CJC-1295 with DAC (drug affinity complex) extends the half-life to approximately 6–8 days, but the sustained elevation blunts natural pulsatility more than MK-677 does.
- Exogenous growth hormone delivers the highest absolute IGF-1 elevation, but it comes with axis suppression. Endogenous GH secretion downregulates in response to chronic exogenous GH, meaning that when you stop, natural production recovers slowly. MK-677 doesn't cause this suppression because it works through endogenous pathways rather than replacing them. For bodybuilders researching MK-677 as an alternative to GH injections, the trade-off is lower peak IGF-1 (60–90% vs 100–200%) in exchange for preserved natural axis function and no injection protocol.