MGF is a splice variant of insulin-like growth factor-1 (IGF-1). MGF is therefore a naturally occurring peptide, though it can be produced synthetically. It has been discovered to play important roles in tissue growth, wound healing, cardiac repair, and more. It is especially important to muscle repair following injury, after weight training, and in the setting of disease. The peptide has increasingly been of interest in research circles for its ability to protect against mechanical overload and lead to healing in otherwise-slow-to-heal tissues like cartilage.