Semaglutide for Treatment of People With Methamphetamine Use Disorder: the SHIFT Study

Inclusion Criteria: 1. Has provided voluntary, written informed consent; 2. Aged 18 years or older; 3. Diagnosed with moderate to severe methamphetamine use disorder (DSM-5 criteria); 4. Self-reported methamphetamine use on at least 14 of past 28 days and a positive oral fluid drug screen for amphetamine/methamphetamine; 5. Willing and able to comply with study procedures and follow-up visits; 6. People of child-bearing potential must agree to use effective contraception during treatment and during the 60 days after treatment end. Exclusion Criteria: 1. Uncontrolled medical or psychiatric conditions that may interfere with participation; 2. Body mass index less than 22 kg/m2; 3. Confirmed diagnosis of diabetes mellitus (either known history of diabetes; concomitant treatment with insulin, metformin, sulfonylureas, thiazolidinediones, SGLT2 inhibitor, DPP4 inhibitor; or HbA1c \>6.5 at screening); 4. Currently taking a GLP-1 receptor agonist; 5. Known hypersensitivity or contraindications to GLP-1 receptor agonists as per product information; 6. Current enrolment in another interventional trial; 7. Lactating, pregnant or at risk of pregnancy not willing to avoid pregnancy 8. History of pancreatitis; 9. History of medullary thyroid cancer; 10. Current admission to a residential rehabilitation program or inpatient program or planned admission during the study period, which would interfere with participation in study visits or procedures; 11. Currently experiencing psychosis or current active suicidality 12. Any condition or circumstance that, in the opinion of the investigator, would compromise the participant's ability to comply with the study procedures, complete protocol requirements, or provide reliable data.