INS and type 2 diabetes mellitus: However, metformin's mechanism of action is not fully understood and its lower risk of hypoglycaemia has only been discussed in relation to SU or insulin.201 Our findings corroborate those seen in the United Kingdom Diabetes Study (UKPDS) where metformin was found to have a higher rate of hypoglycaemia relative to diet alone.202 Nevertheless, metformin remains the most trusted therapy for patients with type 2 diabetes around the world.