Source comparison
MK-677 Half-Life vs Injectable Peptides: A Pharmacokinetic Comparison
MK-677 (Ibutamoren) Oral ~24 hours 2–6 hours post-dose Once daily Sustained receptor occupancy with single daily dose; GH pulses cluster early but IGF-1 elevation persists across 24 hours GHRP-2 Subcutaneous 20–30 minutes 15–30 minutes post-injection 2–3× dail
This comparison does not assign a generated winner or score.
- MK-677 (Ibutamoren)
- Oral
- ~24 hours
- 2–6 hours post-dose
- Once daily
- Sustained receptor occupancy with single daily dose; GH pulses cluster early but IGF-1 elevation persists across 24 hours
- GHRP-2
- Subcutaneous
- 20–30 minutes
- 15–30 minutes post-injection
- 2–3× daily
- Rapid clearance requires multiple daily doses; higher peak GH amplitude but shorter duration
- Hexarelin
- 70 minutes
- 20–40 minutes post-injection
- Slightly longer half-life than GHRP-2 but still necessitates frequent dosing; pronounced desensitisation with chronic use
- CJC-1295 (DAC)
- 6–8 days
- Gradual elevation over days
- Once weekly
- Extended half-life from Drug Affinity Complex conjugation; blunted pulsatility compared to native GHRH
- Sermorelin
- 8–12 minutes
- 10–20 minutes post-injection
- Extremely short half-life; mimics endogenous GHRH pulse but clears rapidly
- Tesamorelin
- 26–38 minutes
- 15–25 minutes post-injection
- Once daily (pre-bed)
- Approved for HIV lipodystrophy; longer half-life than sermorelin allows once-daily dosing
- MK-677's oral bioavailability and 24-hour half-life eliminate the injection burden and dosing frequency constraints that limit peptide secretagogue adoption in extended research protocols. Injectable peptides achieve higher peak GH amplitude in the acute window (GHRP-2 can trigger GH spikes 5–10× baseline within 30 minutes), but MK-677's sustained receptor engagement produces comparable 24-hour IGF-1 AUC without requiring refrigerated storage or sterile reconstitution.