SGLT2i Therapy in Islet Transplantation (SIT)

Inclusion Criteria: * Age 18-70 years old; * \>1 year after TPIAT date at enrollment; * Partial islet function defined as stimulated C-peptide ≥0.6 ng/mL at screening/baseline visit, AND either (1) on insulin at ≤0.25 unit/kg/day OR (2) not on insulin but HbA1c \>6.5%; * Stable diabetes management defined by stable on pump or multiple daily injections (MDI) for at least 8 weeks and \<25% change in insulin dosing over prior 8 weeks. * Willing to manage diabetes medication management/dose adjustments for the duration of the study with study team MD * Willing to wear continuous glucose monitor for diabetes management (currently standard of care for TPIAT diabetes) * Willing to record insulin doses for 14 day intervals x 3 study visits. * Willing and able to come to the UMN Clinical Research Unit for 3 study visits, approximately 3 months apart * No prescribed medications other than insulin to treat diabetes in the past 4 weeks. Exclusion Criteria: * HbA1c \>9%; on any non-insulin antihyperglycemic medication; * History of diabetic ketoacidosis (DKA) in the past 1 year; * Unable to drink Boost HP due to true milk protein allergy; * Underweight (BMI \<18.5 kg/m2) \[contraindicated by possible weight loss with SGLT2 inhibitors\]; * Renal failure defined by glomerular filtration rate \<30 mL/min/m2; * Recurrent dehydration necessitating ED/hospital visits; one time/ rare hospital visits due to intercurrent illness are not exclusionary but repeated dehydration from a chronic condition will be exclusionary. * Expected to need systemic corticosteroids at \>25 mg/day hydrocortisone equivalent over the 6-month study interval; * Known allergy to empagliflozin; * Currently pregnant or plan to become pregnant in the next 6 months (for females), or currently breastfeeding; * Unwillingness to consent or return for study visits; * Non-English speaking. * Any other medical contraindication to treatment or study participation in the opinion of the investigator that would impact either patient's safety or their ability to complete the study.