Aim Evidence of a possible connection between gut microbiota and several physiological processes linked to type 1 diabetes is increasing. However, the effect of multistrain probiotics in people with type 1 diabetes remains unclear. This study investigated the effect of metformin as add-on therapy on glycemic control and other diabetes-related outcomes in people with type 1 diabetes.

Design An open-label, add-on, self-control clinical trial. Setting Diabetes clinic of a teaching hospital in Shenzhen China Participants A total of 20 participants with type 1 diabetes, aged 18-60 years, will be recruited and treated with metformin as add-on therapy with insulin for 12 weeks.

Outcomes Primary outcomes were glycemic control related parameters, and secondary outcomes were anthropomorphic variables, lipid profile, blood pressure and high-sensitivity C-reactive protein. The gut microbiota profile will be analyzed before and after intervention .

Inclusion Criteria:

type 1 diabetes patients age 18-60years old 18 Kg/m2≤BMI≤30Kg/m2 ketonuria (-)；

Exclusion Criteria:

pregnancy lactation having other severe chronic illnesses taking other anti-diabetic drugs