Alleviating Carbohydrate Counting for Patients with Type-1 Diabetes Using a Closed Loop System with Weekly Subcutaneous Semaglutide

Inclusion Criteria: 1. At least 18 years of age 2. A clinical diagnosis of T1D for at least one year, as per their treating diabetes physician in agreement with the primary investigator's clinical judgment (confirmatory C-peptide and antibodies will not be required) 3. Minimum 3-month use of a commercial advanced automated insulin delivery system. 4.4. Agreement to use an effective method of birth control for individuals with child-bearing potential. Child-bearing potential refers to participants of the female sex post-menarche who have not reached menopause and who do not have a medical condition causing sterility (e.g., hysterectomy). Post-menopausal state refers to the absence of menses for 12 months without any alternative cause. Exclusion Criteria: 1. Use of GLP1-RAs within the last 4 weeks. 2. Use of any anti-hyperglycemic agent other than insulin within the last 2 weeks. 3. Planned or ongoing pregnancy 4. Breastfeeding 5. Severe hypoglycemic episode within the last 3 months, defined as an event where glucose was \< 4 mmol/L resulting in seizure, loss of consciousness, or need to present to the emergency department 6. Severe diabetic ketoacidosis (DKA) within the last 6 months ("severe" referring to need to present to medical attention and requirement of intravenous insulin) 7. Prior history of acute pancreatitis, chronic pancreatitis, or gallbladder disease 8. Personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2 9. Severe impairment of renal function with eGFR \<30 mL/min/1.73 m2 (using CKD-EPI formula), measured within the last 12 months 10. Clinically significant diabetic retinopathy or gastroparesis, as per the clinical judgment of the investigator 11. Bariatric surgery within the last 6 months. 12. A serious medical or psychiatric illness that is likely to interfere with study participation as per the judgment of the investigator (e.g. cirrhosis, active cancer, decompensated schizophrenia). 13. Body mass index ≤ 21 kg/m2 14. Inability or unwillingness to comply to safe diabetes management in the view of the study group (e.g. inappropriate treatment of hypoglycemia or lack thereof) 15. Concern for safety of the participant, as per the clinical judgment of the primary investigator