IGF1 and acne: Metformin not only increases insulin sensitivity when inhibiting mTORC1 (mammalian target of rapamycin complex 1) and reducing IGF-1 (insulin-like growth factor-1) serum levels, leading to androgen signaling suppression, but also presents anti-inflammatory properties that eventually cause a reduction in the GAGS score (the global acne grading system) and the disappearance of acne lesions [34].