IGF-1 LR3 Guide: Benefits, Uses & Risks for Bodybuilding 🔍 What is IGF-1 LR3? IGF-1 LR3 (Insulin-Like Growth Factor-1 Long R3) is a modified version of natural IGF-1, a hormone involved in cell growth, recovery, and muscle development. The LR3 variant has a longer half-life, meaning it stays active in the body longer than standard