IGF-1 (Insulin-Like Growth Factor 1)
Also known as: Insulin-Like Growth Factor 1
IGF-1 is a liver-produced peptide hormone that mediates most of the anabolic effects of growth hormone. IGF-1 LR3 is a long-acting synthetic analogue used in research.
Overview
IGF-1 is a 70-amino-acid peptide structurally similar to insulin that acts as the primary mediator of GH's anabolic and growth-promoting effects. When GH stimulates the liver, hepatocytes produce and secrete IGF-1 into circulation, where it acts on IGF-1 receptors throughout the body to promote cell growth, protein synthesis, and differentiation. IGF-1 levels are commonly used in research as a biomarker of GH activity. IGF-1 LR3 is a long-acting research analogue with a single arginine substitution and an N-terminal extension that reduces insulin-like receptor binding, shifting its activity toward IGF-1 receptors and extending its half-life from minutes to 20–30 hours.
Related Peptide Profiles
Frequently asked questions
How does IGF-1 relate to HGH?+
GH stimulates the liver to produce IGF-1. Most of HGH's anabolic effects are actually mediated downstream by IGF-1. Researchers often measure IGF-1 levels as a proxy for GH activity.
What makes IGF-1 LR3 different from natural IGF-1?+
IGF-1 LR3 has structural modifications that extend its half-life from a few minutes to approximately 20–30 hours and reduce its affinity for IGF-binding proteins, resulting in more sustained biological activity.
Is IGF-1 the same as insulin?+
No, but they are structurally related. IGF-1 shares about 50% sequence homology with insulin and can bind insulin receptors at high concentrations, which is why its hypoglycemic potential is a consideration in research protocols.