What is the maximum weight loss expected after one year?

After 12 months on maximum-dose GLP-1 therapy, average weight loss is 15-17% for semaglutide (STEP trials) and 20-22% for tirzepatide (SURMOUNT trials). A 300-pound person could expect to lose 45-66 pounds on average. Some patients achieve 25-30% weight loss, while others lose 10-15%. Maximum results typically require staying at the highest tolerated dose (2.4mg semaglutide or 15mg tirzepatide) for at least 6 months. By month 12, weight loss often plateaus as the body reaches a new equilibrium. Long-term data beyond 2 years shows maintained weight loss of 12-15% on average for patients who continue medication.