['type 1 diabetes']
['metformin', 'placebo']

        Inclusion Criteria:

        1. Meets eligibility criteria of the main study, Metformin Therapy for Overweight
        Adolescents With Type 1 Diabetes (NCT01881828).

        Exclusion Criteria:

        1. Low hemoglobin or hematocrit as defined by each local institution's rules for insulin
        clamps or if no institutional requirements a Hematocrit <30% or hemoglobin <10 gm/dL
      