IGF-1 LR3 Overview
Mechanism of Action
IGF-1 LR3 is a modified IGF-1 with an arginine substitution at position 3 and a 13-amino-acid N-terminal extension. These reduce binding to IGF-binding proteins, resulting in greater bioavailability and a ~20-hour half-life vs ~15 minutes for native IGF-1. Promotes cell proliferation, protein synthesis, and glucose uptake.
~20–30 hours
Timing
Post-workout or morning
Injection Site
Subcutaneous
Food
Consider with carbohydrates to manage blood sugar
Common Stacks
- Growth hormone — IGF-1 mediates many GH effects
- BPC-157/TB-500 — Recovery synergy
IGF-1 LR3 Dosing Protocol
Standard Protocol
4–6 weeks50–100 mcg SQ daily
Post-workout. Cycle 4 weeks on / 4 weeks off.
Conservative
4 weeks20–50 mcg SQ daily
Lower dose for initial assessment.
IGF-1 LR3 Expected Timeline
Week 1–2
Enhanced muscle pumps; improved recovery
Week 3–4
Increased muscle fullness
Week 4–6
Measurable lean mass improvements
IGF-1 LR3 Side Effects
Hypoglycemia
Joint pain
Injection site irritation
IGF-1 LR3 Research Studies
IGF-1 in skeletal muscle regeneration
Musaro A, et al. — Proc Natl Acad Sci USA (2001)
Demonstrated IGF-1 plays a critical role in skeletal muscle regeneration, promoting satellite cell proliferation for repair and hypertrophy.
PubMed: 11707567IGF-1 LR3 FAQ
Difference between IGF-1 LR3 and IGF-DES?
IGF-1 LR3 has long half-life (~20+ hr) for systemic effects. IGF-DES has extremely short half-life (~20–30 min) but 10x stronger receptor binding, better for localized site-specific injection.
Why does IGF-1 LR3 cause hypoglycemia?
IGF-1 binds insulin receptors (weakly) and promotes glucose uptake independently. Having carbohydrates after administration helps prevent this.