comparing the novel agent DPP-4 inhibitor with the conventional Thiazolidinediones and Biguanides namely Metformin, it seems that Metformin is better option, not only it causes weight loss which is desired in most obese patients with diabetes, it also decreases the incidence of cancer as well as reducing macrovascular and microvascular complications, whereas the other 2 agents have much more side effects, some even life-threatening.