Weight-loss projection
Mean weight trajectories from the landmark trials, applied to your starting weight. Useful for setting realistic expectations. Individual response varies by ±5–10 percentage points; this is the population mean, not a personal forecast.
Medication
Projected at week 68
171.6 lbs
−22.0% TBWL
Goal achievement
week 42
based on mean trial trajectory
Required TBWL for goal
18.2%
from 220 to 180 lbs
⚠ This is a population-mean projection, not a personal forecast.
Trial averages mask substantial individual variance. STEP-1 reported a standard deviation of ±6.6 percentage points around its 14.9% mean — meaning roughly 1-in-6 patients lose less than 8% and roughly 1-in-6 lose more than 22%. The same pattern holds for tirzepatide and retatrutide. Your trajectory will land somewhere on a wide distribution, not on the line shown above.
Body composition matters: lean-mass loss accounts for ~25–40% of total weight lost on GLP-1s without resistance training. See our muscle-preservation guide for the protein + training protocol that mitigates this.
Not medical advice. Discuss expectations and contraindications with your prescribing clinician.