IGF-1 is a hormone responsible for long bone growth in children and muscle growth and repair in adults. IGF1-LR3 is a more potent version of IGF-1 that induces muscle hyperplasia and increases muscle cell growth. It has a longer half-life and causes localized IGF levels to rise. It can also increase the uptake of supplements and prevent muscle loss in PCT. Its potency is due to decreased binding to IGF binding proteins.
# Muscle growth
This study aimed to test the hypothesis that a new myostatin inhibitor, a recombinant myostatin propeptide, can enhance the repair and regeneration of both muscle and bone in cases of deep penetrant injury. The study used a fibula osteotomy model with associated damage to lateral compartment muscles in mice. The results showed that blocking active myostatin with systemic injections of a recombinant myostatin propeptide improved muscle and bone repair.