IGF-1 LR3

Product Overview

IGF-1 LR3 differs from native IGF-1 through an arginine substitution at position 3 and an additional 13 N-terminal amino acids (total: 83 amino acids vs. 70). These modifications dramatically reduce binding to IGF-binding proteins (IGFBPs), resulting in enhanced metabolic stability, approximately 3x potency, and a half-life of 20–30 hours compared to IGF-1's 12–15 hours.

Mechanism of Action

IGF-1 LR3 binds to IGF-1 receptors, activating the IGF1R/IRS1/PI3K/Akt signaling cascade. This promotes protein synthesis, cell repair, glucose uptake, and fat oxidation in skeletal muscle. Its reduced IGFBP affinity means more free peptide is available for receptor activation, resulting in sustained and potent anabolic signaling.

Key Benefits

Muscle Growth & Repair — Activates the PI3K/Akt cascade leading to skeletal muscle hypertrophy. Promotes muscle stem cell proliferative potential for repair and regeneration. Inhibits muscle proteolysis, preserving muscle protein and mass.

Extended Duration of Action — 20–30 hour half-life provides sustained anabolic activity, requiring less frequent dosing compared to native IGF-1.

Metabolic Enhancement — Improves glucose uptake and encourages fat oxidation, contributing to improved body composition when combined with exercise and nutrition.

Recovery Acceleration — Supports tissue recovery through enhanced protein synthesis, cell proliferation, and growth factor signaling in skeletal muscle.

References

1. Tomas FM, et al. Superior potency of infused IGF-I analogues which bind poorly to IGF-binding proteins. *J Endocrinol.* 1996;150(1):77–84.
2. Langlois S, Cowan KN. Regulation of skeletal muscle myoblast differentiation and proliferation by pannexins. *Adv Exp Med Biol.* 2017;925:57–73.
3. Musaro A. IGF-1 and skeletal muscle hypertrophy. *Biochem Soc Trans.* 2013;41(6):1451–1456.