Two and a half years ago, I was diagnosed with type 1 diabetes (DKA at that time) and was initially put on insulin injections, but, four months later, I went into a honeymoon stage which lasted 8 months after diagnosis. After the honeymoon stage, I was put on metformin with diet and exercise, but, after six months, went back on insulin injections to control my blood sugar. My blood sugar is under control now with an HbA1c of 6.3%. I had a C-peptide done very recently which was 3.2 ng/ml (normal range of.64-2.83ng/ml) and have several questions regarding this.

Does this result indicate insulin resistance?
Is my classification type 1 or type 2 diabetes?
Is the honeymoon period typical of type 1 and type 2 diabetes?
Why does taking insulin injections control my blood sugar levels when there is enough insulin reserve, whereas metformin did not help?

From all the evidence you have provided, I would suggest you have type 1 diabetes because you had DKA [diabetic ketoacidosis], usually a type 1 feature. However, some individuals who are markedly obese can have DKA only to revert to better control and using oral hypoglycemic agents. Secondly, you did not have adequate control with an oral agent. Third, a honeymoon phase is more indicative of type 1 diabetes. The C-peptide level you report does suggest you make some insulin. Obviously it is not enough or you would have better blood sugars and not need insulin.

The natural history in type 1 diabetes is for the C-peptide level to fall over time. This suggests continuous autoimmune damage to the remaining islet cells. There is a possibility that you have insulin resistance, but I would have to know more about you. Are you overweight or obese? Do you have elevated lipids? What is your family history for diabetes? Finally, true insulin resistance is measured using a variety of tests that are not necessarily part of everyday medicine.

JTL