Source comparison
IGF-1 LR3 vs Native IGF-1 vs MK-677: Week-One Response Comparison
IGF-1 LR3 Direct IGF-1 receptor agonist with reduced IGFBP binding Enhanced vascularity, improved pump, glycogen supercompensation, 8–12% FSR increase 20–30 hours Fastest onset of receptor-mediated effects. Observable changes within 4–7 days but no measurable
This comparison does not assign a generated winner or score.
- IGF-1 LR3
- Direct IGF-1 receptor agonist with reduced IGFBP binding
- Enhanced vascularity, improved pump, glycogen supercompensation, 8–12% FSR increase
- 20–30 hours
- Fastest onset of receptor-mediated effects. Observable changes within 4–7 days but no measurable hypertrophy
- Native IGF-1
- Direct IGF-1 receptor agonist with high IGFBP affinity
- Minimal observable changes due to rapid sequestration by binding proteins
- 12–15 hours
- Requires significantly higher doses to achieve comparable free IGF-1 levels. Less practical for research
- MK-677 (Ibutamoren)
- Growth hormone secretagogue. Increases endogenous GH and IGF-1 production
- Increased appetite, minor water retention, no observable anabolic effects in week one
- 24 hours (for the secretagogue), but GH pulses occur in 4–6 hour intervals
- Indirect pathway. Endogenous IGF-1 elevation takes 10–14 days to plateau, making week-one comparison irrelevant
- CJC-1295/Ipamorelin Stack
- GHRH analogue + ghrelin mimetic. Stimulates pulsatile GH release
- Improved sleep quality, minor recovery benefits, no measurable anabolic signaling in week one
- CJC: 6–8 days; Ipamorelin: 2 hours
- Peptide stack requires 2–3 weeks to elevate baseline IGF-1 sufficiently for anabolic effects. Week one shows GH effects only
- IGF-1 LR3 delivers the fastest receptor-level response because it bypasses endogenous production pathways entirely. Native IGF-1 and secretagogues like MK-677 or CJC-1295/Ipamorelin require multi-week timelines to show comparable anabolic signaling. If the research objective is to isolate IGF-1-mediated effects within a controlled short-term window, IGF-1 LR3 is the most direct tool.