How accurate is the GLP-1 weight-loss projection?

The mean projection is grounded in published phase-3 trial data (STEP-1 for semaglutide, SURMOUNT-1 for tirzepatide). Individual response varies — about 1 in 3 trial participants achieved ≥20% weight loss; about 1 in 6 lost less than 5%. The 25th–75th percentile band reflects this real variance.

Why does the projection plateau toward week 68?

Weight-loss curves on GLP-1 receptor agonists decelerate. Most loss happens in weeks 12-44; by week 60 the curve flattens as your body reaches a new energy-balance setpoint.

What happens if I stop taking the drug?

Trial extension data (STEP-1 follow-up, SURMOUNT-4 withdrawal) shows roughly two-thirds of lost weight is regained within 12 months of stopping. GLP-1 therapy for weight management is FDA-labeled for chronic use.

Trial-grounded calculator

GLP-1 weight-loss projection

Enter your starting weight and pick a drug + dose. We project your trajectory through 68 weeks using the mean from the pivotal phase-3 trials (STEP-1, SURMOUNT-1), plus the 25th–75th percentile band so you see realistic variance — not just a single number.

Starting weight

Drug + dose

Trial-grounded mean projection

187 lb(−33 lb)

Mean projection at 68 weeks. Typical range: 176–198 lb (25th–75th percentile in pivotal trials).

Week	Mean weight	Lost	Typical range
12	206 lb	−14 lb	202–211 lb
24	198 lb	−22 lb	191–205 lb
36	194 lb	−26 lb	185–202 lb
48	191 lb	−29 lb	181–200 lb
60	189 lb	−31 lb	179–199 lb
68	187 lb	−33 lb	176–198 lb

Projection is editorial illustration based on published trial means (STEP-1, SURMOUNT-1). Individual response varies; some people lose 5%, others 30%. Not personal medical advice. Discuss expected outcomes with a licensed prescriber.

After your projection — next steps

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Important — this is not medical advice

Informational only. This tool does not diagnose, treat, or replace your prescriber. Confirm anything here with a licensed clinician who knows your full history, conditions, and labs.
Results are estimates. Weight-loss projections are population-average estimates from clinical-trial data. Your actual result depends on dose, adherence, diet, activity, and individual biology — many people lose more or less.
Sourced from FDA prescribing information and peer-reviewed data; labels update and we re-verify periodically.
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