Source comparison
Comparison: MK-677 vs IGF-1 LR3 vs Stacked Protocol
Mechanism Ghrelin receptor agonist → endogenous GH pulsatility → hepatic IGF-1 synthesis Direct IGF-1 receptor activation, bypasses GH axis entirely Dual-pathway: sustained baseline (MK-677) + acute peaks (LR3) Stack leverages temporal complementarity. Not red
This comparison does not assign a generated winner or score.
- Mechanism
- Ghrelin receptor agonist → endogenous GH pulsatility → hepatic IGF-1 synthesis
- Direct IGF-1 receptor activation, bypasses GH axis entirely
- Dual-pathway: sustained baseline (MK-677) + acute peaks (LR3)
- Stack leverages temporal complementarity. Not redundancy
- IGF-1 Elevation
- 40–90% above baseline, dose-dependent, filtered through IGFBPs
- Direct tissue-level activation, 90% reduced IGFBP binding
- Baseline +40–90% (MK-677) with superimposed LR3 peaks
- Stacked elevation is additive in tissue exposure, not serum concentration
- Dosing Frequency
- Once daily (evening preferred)
- 1–2x daily (post-training, pre-sleep)
- MK-677 1x daily + LR3 2x daily
- Timing separation preserves distinct anabolic windows
- Half-Life
- 4–6 hours (GH pulse), IGF-1 synthesis peaks 6–8 hours later
- 20–30 hours (LR3 remains bioavailable across dosing interval)
- Overlapping but non-redundant kinetics
- MK-677's short half-life with pulsatile GH + LR3's extended half-life = 24-hour coverage
- Insulin Sensitivity Impact
- Moderate reduction (GH-induced lipolysis antagonizes insulin signaling)
- Mild reduction (IGF-1R activation competes with IR substrates)
- Significant reduction. Both pathways compound
- Stacked protocols require fasting glucose monitoring every 4–6 weeks
- Receptor Desensitization Risk
- Low (pulsatile GH maintains receptor sensitivity)
- Moderate (continuous IGF-1R occupancy can downregulate receptor density)
- Elevated (overlapping pathways increase total receptor occupancy time)
- Cycling both compounds simultaneously mitigates desensitization. 8–12 weeks on, 4 weeks off