Zepbound Weight Loss Calculator

How the Zepbound Weight Loss Calculator Works

Our Zepbound calculator uses dose-specific weight loss models derived from the SURMOUNT-1 clinical trial — the landmark study of tirzepatide published in the New England Journal of Medicine. In this 72-week trial, participants on the highest dose (15mg) lost an average of 20.9% of their body weight, making tirzepatide the most effective GLP-1 medication studied to date.

Zepbound is the FDA-approved weight management version of tirzepatide (the same active ingredient as Mounjaro). It was approved in November 2023 specifically for chronic weight management in adults with obesity (BMI ≥ 30) or overweight (BMI ≥ 27) with at least one weight-related condition.

Zepbound Weight Loss by Starting Weight

Here's what the SURMOUNT-1 data suggests for tirzepatide 15mg at different starting weights:

Zepbound Dosing Schedule

Zepbound follows the same tirzepatide dose-escalation schedule as Mounjaro. Each dose is maintained for at least 4 weeks before increasing:

Zepbound vs Ozempic: Which Is Better for Weight Loss?

Both are GLP-1-based medications, but they work differently. Zepbound (tirzepatide) is a dual GIP/GLP-1 receptor agonist, targeting two hormonal pathways that control appetite and metabolism. Ozempic (semaglutide) targets only GLP-1 receptors.

The result: tirzepatide produces substantially more weight loss. SURMOUNT-1 showed 20.9% body weight loss on tirzepatide 15mg versus 14.9% on semaglutide 2.4mg in STEP-1 — a 40% greater effect. However, Ozempic has a longer real-world safety track record.

Want to compare all GLP-1 medications side by side? Try our GLP-1 Weight Loss Calculator, or see separate projections for Ozempic and Mounjaro.

Zepbound vs Mounjaro: What's the Difference?

Zepbound and Mounjaro are the same molecule — tirzepatide — made by Eli Lilly. The only differences are:

• Mounjaro is FDA-approved for type 2 diabetes management
• Zepbound is FDA-approved for chronic weight management (obesity/overweight)
• Insurance coverage and copay assistance programs differ between the two
• The doses, injection pen, and weight loss effects are identical

Frequently Asked Questions

How much weight will I lose on Zepbound?

In the SURMOUNT-1 clinical trial, patients on tirzepatide 15mg (Zepbound's highest dose) lost an average of 20.9% of their body weight over 72 weeks. For a 230 lb person, that's approximately 48 lbs. Results vary by dose: 5mg averages 15%, 10mg averages 19.5%, and 15mg averages 20.9%.

How long does it take to see results on Zepbound?

Most patients notice reduced appetite within the first week and measurable weight loss by weeks 4-6. Significant visible changes typically appear by months 3-4 as you titrate to therapeutic doses. Peak weight loss usually occurs between months 9-15 on the highest tolerated dose.

What is the difference between Zepbound and Mounjaro?

Zepbound and Mounjaro both contain tirzepatide made by Eli Lilly. Mounjaro is FDA-approved for type 2 diabetes, while Zepbound is FDA-approved specifically for chronic weight management. The active ingredient, doses (2.5mg-15mg), and injection device are identical — the difference is the approved indication and insurance coverage.

Is Zepbound better than Ozempic for weight loss?

Clinical trials show Zepbound (tirzepatide) produces significantly greater weight loss than Ozempic (semaglutide). SURMOUNT-1 showed 20.9% body weight loss on tirzepatide 15mg compared to 14.9% on semaglutide 2.4mg in STEP-1. Tirzepatide targets two hormonal pathways (GIP + GLP-1) versus one for semaglutide.

What is the Zepbound dosing schedule?

Zepbound starts at 2.5mg weekly for 4 weeks (initiation dose), then increases to 5mg. Your doctor may increase by 2.5mg every 4 weeks based on tolerability, up to the maximum of 15mg weekly. Available doses: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, and 15mg.