IGF-1 LR3

Modified IGF-1 with 2-3x potency and extended half-life due to reduced binding protein affinity. Potent activator of muscle growth and protein synthesis.

Overview

Also Known As

Long R3 IGF-1, Long Arginine 3-IGF-1, LR3-IGF-1

Mechanism of Action

Binds IGF-1R with native affinity, dramatically reduced IGFBP binding. Activates PI3K/Akt and MAPK/ERK pathways for protein synthesis, satellite cell activation, myogenesis, glucose uptake, and anti-apoptosis.

Product

Long R3 IGF-1, Long Arginine 3-IGF-1, LR3-IGF-1 vial

Dosing & Administration

Typical protocols and routes

Half-Life

20-30 hours (vs 12-15 minutes for native IGF-1)

Administration Routes

subcutaneousintramuscular

Dosing Protocols

Reconstitute vial with 2 mL bacteriostatic water, giving 20 equal doses. Draw 10 units per day on insulin syringe (marked 0-100). Vial lasts 20 days.

Research

Key findings and status

Key Research Findings

Barton-Davis et al.: IGF-1 overexpression increased muscle mass 15-30% in aged mice. Francis et al.: demonstrated 2-3x potency vs native IGF-1. Standard in cell culture applications.

Detailed Information

IGF-1 LR3 (Long R3 IGF-1) is a modified insulin-like growth factor 1 with an arginine substitution at position 3 and a 13-amino acid N-terminal extension. These modifications reduce IGF-binding protein affinity, resulting in 2-3 times greater potency than native IGF-1 with a significantly extended half-life.

Mechanism of Action

IGF-1 LR3 binds IGF-1R with native affinity but with greatly reduced IGFBP binding. Since IGFBPs normally sequester 95%+ of circulating IGF-1, this means a much higher proportion of free bioactive hormone. Activates PI3K/Akt and MAPK/ERK pathways, promoting protein synthesis, satellite cell activation, myogenesis, and glucose uptake.

Research Applications

Widely used in cell culture to promote cell proliferation. Barton-Davis et al. showed IGF-1 overexpression increased muscle mass 15-30% and improved strength in aged mice. Site-specific injections produce localized muscle growth in animal models.

Safety & Legal

Side Effects & Warnings

Hypoglycemia (significant risk), joint/muscle pain, edema, potential tumor promotion via IGF-1R pathway. Organ enlargement possible with chronic high-dose use.

Legal Status

Research use only

Molecular Data

Chemical properties

Molecular Weight

9111.4 g/mol

Amino Acid Sequence

83-amino acid modified IGF-1: 13-AA N-terminal extension + Arg3 substitution