Weight Loss Projector
A 12-month projection curve built from the clinical trials.
Projected at 12 months
180lb
Total lost
−40lb
≈ 18.4% of body weight
Based on the mean total weight loss reported in SURMOUNT-1 (20.9% on Tirzepatide 15mg). Trial averages hide huge individual variation — your curve depends on dose, diet, muscle, and consistency. This is an educational estimate, not a promise.
What the trials actually showed
The headline numbers come from two landmark trials. In STEP 1, adults on semaglutide 2.4 mg lost an average of ~14.9% of body weight over 68 weeks. In SURMOUNT-1, tirzepatide 15 mg produced ~20.9% over 72 weeks. Those are averages at the maximum maintenance dose, after full titration.
Why your curve bends, not spikes
Weight loss on GLP-1s is front-loaded: the biggest drops come in the first few months, then the rate eases as your body approaches a new set point. That's why this projector uses a curve that rises quickly and flattens, rather than a straight line. A plateau isn't failure — it's the expected shape.
The honest caveat
Trial averages hide enormous individual variation. Some people well exceed the mean; others land below it. Your real trajectory depends on your starting weight, dose, diet (especially protein), muscle mass, activity, and consistency. Treat this as an educational estimate to set expectations, never a personal guarantee — and track your real numbers as you go.
Frequently asked
- How much weight can you lose on tirzepatide or semaglutide?
- In trials, average total body-weight loss reached about 20.9% on tirzepatide 15 mg (SURMOUNT-1) and 14.9% on semaglutide 2.4 mg (STEP 1). Individual results vary widely around those averages.
- How fast does GLP-1 weight loss happen?
- It is front-loaded. The steepest loss is usually in the first few months, then it slows as you approach a new set point. Most trials ran 15–18 months to reach the averages above.
- Is this projection a guarantee of my results?
- No. It reshapes clinical-trial averages into a curve for your starting weight to set expectations. Your actual outcome depends on dose, diet, muscle, activity, and consistency, and can land well above or below the average.
- Why did my weight loss plateau?
- Plateaus are expected as your body reaches a new equilibrium. Protein intake, resistance training, sleep, and dose can all influence when it happens. A stall in scale weight does not mean body composition has stopped improving.
Medical disclaimer. Tiro is a tracking companion, not a medical device, and nothing on this site is medical advice. Always follow the titration schedule and dosing instructions from your prescriber. Never change your dose without talking to them first.