IGF-1 LR3
Long R3 Insulin-like Growth Factor-1
IGF-1 LR3 is a synthetic analog of human insulin-like growth factor 1, engineered with an arginine substitution at position 3 and 13 additional amino acids at the N-terminus. This 83-amino acid peptide exhibits reduced affinity for IGF-binding proteins, resulting in a prolonged half-life of 20-30 hours and approximately 3 times greater potency than native IGF-1. Currently investigational and not FDA-approved for human use.
Clinical Benefits
Mechanism of Action
IGF-1 LR3 binds to and activates the IGF-1 receptor (IGF-1R), a transmembrane tyrosine kinase receptor. Upon binding, IGF-1R undergoes autophosphorylation and activates downstream signaling cascades including the PI3K-Akt pathway (promoting protein synthesis and cell survival) and the MAPK pathway (stimulating cellular proliferation and differentiation). The key modification—arginine substitution at position 3 and 13 N-terminal amino acids—significantly reduces binding to IGF-binding proteins (IGFBPs), particularly IGFBP-3, resulting in increased bioavailability and extended half-life. This enhanced bioactivity allows for more sustained activation of anabolic pathways in target tissues, particularly skeletal muscle, where it stimulates satellite cell activation, myofibrillar protein synthesis, and muscle fiber hypertrophy.
Proven Results
Medical Disclaimer
IGF-1 LR3 is an investigational research compound not approved by the FDA for human therapeutic use. This information is provided for educational purposes only and should not be construed as medical advice. IGF-1 LR3 carries significant risks including severe hypoglycemia and potential tumor growth acceleration. Any use should only occur under strict medical supervision in approved research settings. Individuals with cancer history, diabetes, or other serious medical conditions should not use this compound.