GDF15 and type 2 diabetes mellitus: Metformin use was found to be associated with increased levels of growth differentiation factor 15, which is a stress responsive cytokine of the transforming growth factor-β family, affecting the intestine, skeletal muscles and the liver.[52] Growth differentiation factor 15 is in turn associated with Metformin induced weight loss in patients with T2DM independently of its intended glycemic effects.