Zepbound (tirzepatide)
Zepbound is a weekly injection product containing tirzepatide, made by Eli Lilly. Its approved use in the U.S. is weight management.
Educational information. This page does not give dosing instructions or tell you what to take. The current label and a prescriber decide that.
What Zepbound is
- Generic name
- Tirzepatide
- Maker
- Eli Lilly
- Form
- Weekly injection
- U.S. approved use
- Weight management
- First U.S. approval
- 2023
How it differs from related products
Zepbound and Mounjaro both contain tirzepatide as a weekly injection, but they are separate products with different approved uses. Zepbound is approved for weight management. Mounjaro is approved for type 2 diabetes.
| Product | Form | U.S. approved use | Status |
|---|---|---|---|
| Zepbound (this page) | Weekly injection | Weight management | FDA-approved for weight management |
| Mounjaro | Weekly injection | Type 2 diabetes | FDA-approved, but not for obesity |
What it is approved for
- Reducing excess body weight and keeping it off, in adults with obesity or overweight plus a weight-related condition
- Moderate to severe obstructive sleep apnea in adults with obesity
How it is taken
Weekly injection. Follow the label and your prescriber for how to use it.
What the trials found
These are group averages from published trials of this product's weight-management use, in adults without diabetes.
SURMOUNT-1
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 2,539 adults with obesity, or overweight plus at least one weight-related complication, without diabetes
- Length
- 72 weeks
- Compared with
- Placebo, including a 20-week dose-escalation period
- What was measured
- Average change in body weight at week 72
- Analysis approach
- Treatment-regimen estimand: effects regardless of treatment discontinuation
- Other results
- Weight loss of at least 5%: 85%, 89% and 91% across the three doses vs 35% with placebo. At least 20%: 50% (10 mg) and 57% (15 mg) vs 3%.
- Safety
- Most side effects were gastrointestinal, mostly mild to moderate, and mainly during dose escalation. Stopping treatment because of side effects: 4.3%, 7.1% and 6.2% across the three doses vs 2.6% with placebo.
- Limits
- Funded by the manufacturer. Participants did not have diabetes. Group averages do not predict one person's result.
Sources: Jastreboff AM 2022
SURMOUNT-5
Average change in body weight. Every bar uses one scale, 0 to 25 percent.
- People studied
- 751 adults with obesity but without type 2 diabetes
- Length
- 72 weeks
- Compared with
- Semaglutide, head to head. Open label, so participants and staff knew which drug was used. No placebo group.
- What was measured
- Average percent change in body weight at week 72
- Analysis approach
- Least-squares mean change from baseline to week 72, as reported in the abstract.
- Other results
- Waist circumference fell 18.4 cm with tirzepatide vs 13.0 cm with semaglutide. More people on tirzepatide reached weight loss of at least 10%, 15%, 20% and 25%.
- Safety
- Gastrointestinal effects were the most common side effects in both groups. Most were mild to moderate and happened mainly while the dose was being raised.
- Limits
- Funded by Eli Lilly, the maker of tirzepatide. Open label. Each person took the highest dose they could tolerate, so the doses were not identical across people. Group averages do not predict one person's result.
Sources: Aronne LJ 2025
Safety
Warnings, side effects and open questions for tirzepatide are on the tirzepatide page. The official label is the controlling source.
Compiled from public information: FDA-approved labels, manufacturer websites, ClinicalTrials.gov and published journal articles. Sources are listed at the bottom of this page.
Related
Sources
- Zepbound (tirzepatide) injection: prescribing information Eli Lilly and Company, on DailyMed (U.S. National Library of Medicine). Label version 8/2026. Official FDA label on DailyMed
- DailyMed: current FDA drug labels U.S. National Library of Medicine. Regulator
- Drugs@FDA: approved drug products U.S. Food and Drug Administration. Regulator
- Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1) Jastreboff AM, et al. N Engl J Med. 2022;387(3):205-216. PMID 35658024. Funding: Eli Lilly. Journal article
- Tirzepatide as compared with semaglutide for the treatment of obesity (SURMOUNT-5) Aronne LJ, et al. N Engl J Med. 2025;393(1):26-36. PMID 40353578. Funding: Eli Lilly. Journal article