Localized Igf 1 transgene expression sustains hypertrophy and regeneration in senescent skeletal muscle Nature Genetics The mighty protein: insulin like growth factor type 1 The Physiological Society Discover IGF 1 (Insulin like Growth Factor 1), a key player in muscle development and overall growth! This essential peptide stimulates protein synthesis, helping to build lean muscle mass and enhance recovery after workouts. IGF 1LR3 IGF1 stimulates greater muscle hypertrophy in the absence of myostatin in male mice in: Journal of Endocrinology Volume 234 Issue 2 (2017)