Yes it is possible to be on both drugs at the same time, however there exists a potential interaction between sex hormones and insulin. Taking testosterone or oestrogen together with insulin or certain other diabetes medications may interfere with blood glucose control as they can cause low blood sugar, and/or exacerbate pre-existing diabetes. Close monitoring for the development of low or high blood sugar symptoms is recommended if you take hormones together with insulin, particularly in patients with advanced age or kidney problems. According to the degree of your symptoms, you may need a simple readjustment of your insulin dose.