The goal of the study is to assess how tirzepatide impacts bodyweight and cardiovascular risk factors when used in conjunction with healthy nutrition and physical activity in adolescents with obesity and multiple weight related comorbidities. The study will last approximately 76 weeks and may include up to 23 visits. Participants who have completed the primary 72-week GPIX study and have been off treatment for no more than 12 weeks (including the 4-week safety follow-up period), will have the opportunity to receive an additional 156 weeks of treatment with tirzepatide as well as continuing the lifestyle intervention.