IGF-1 LR3

Description

IGF-1 LR3 (Long R3 Insulin-Like Growth Factor-1)

Overview: IGF-1 LR3 is a laboratory-made analogue of human IGF-1. It features two modifications: an arginine substitution at position 3 (Arg3 instead of Glu3) and the addition of 13 amino acids to the N-terminus. This results in an 83-amino-acid peptide (versus 70 in native IGF-1) with greatly increased stability, potency, and reduced binding to IGF-binding proteins (IGFBPs).

Mechanism of Action

IGF-1 LR3 activates the IGF-1 receptor (IGF-1R), triggering intracellular pathways such as PI3K/AKT and MAPK. These pathways regulate cell growth, survival, protein synthesis, and glucose uptake. Because LR3 binds poorly to IGFBPs, it remains more available to activate receptors, making it more potent and longer-lasting than native IGF-1.

Pharmacokinetics — Why LR3 Is “Long”

The structural modifications extend IGF-1 LR3’s circulating half-life to approximately 20–30 hours (varies by model), compared with much faster clearance of native IGF-1. Reduced binding to IGFBPs further enhances receptor exposure and biological effect.

Metabolic Effects

IGF-1 signaling enhances glucose uptake in muscle and can lower blood glucose acutely, giving it insulin-like properties in addition to its growth-promoting actions.

Research and Preclinical Evidence

• Therapeutic interest: IGF-1 analogues have been studied in the context of growth, tissue repair, and metabolic regulation.
• Preclinical data: In vitro and animal studies demonstrate potent anabolic and tissue-growth effects of IGF-1 LR3.

Bottom Line

IGF-1 LR3 is a long-acting, more potent analogue of native IGF-1. Research shows extended activity and robust anabolic effects, making it a valuable tool for laboratory investigation.

Research Use Only: IGF-1 LR3 is supplied strictly for laboratory and research purposes. It is not approved for human consumption, medical, or veterinary use.