Evidence-graded answer
How fast do results show on GLP-1?
Appetite changes in 1-2 weeks. Visible weight loss usually starts in week 4-6. Significant fat loss accelerates in weeks 12-44 as the dose escalates.
Week 1-2: appetite signals shift; "food noise" decreases.
Week 3-4: 1-3 lb loss is typical, mostly water shift from reduced food + carb intake.
Week 5-12: sustained 0.5-1.5 lb/week as titration proceeds.
Week 12-44: most of the trial-average loss (10-22%) occurs.
Week 44-68: deceleration to a plateau, with continued slow loss for many patients.
Source: STEP-1 secondary endpoints, NEJM 2021