GCG and diabetes mellitus: In case of the presence of hyperglycemia, type 2 diabetes mellitus, or acanthosis nigricans, next to exercise, the first choice for pharmaceutical intervention is metformin (126); other options include diazoxide and metformin (127), Tesomet (128), octreotide (129-131), combination of oral phentermine and topiramate (Ph/T) (132, 133), or GLP-1 analogues (3, 17, 134-136).