Zepbound (tirzepatide) and Wegovy (semaglutide) are both weekly subcutaneous injections approved for chronic weight management. Zepbound activates two incretin receptors — GIP and GLP-1 — while Wegovy activates only the GLP-1 receptor. In the head-to-head SURMOUNT-5 trial, Zepbound produced approximately 20 percent body weight reduction versus approximately 14 percent for Wegovy. Wegovy has a cardiovascular risk reduction indication; Zepbound’s cardiovascular outcome trial is pending. Which is right for you depends on weight-loss goals, cardiovascular profile, tolerability, and insurance coverage.
Side-by-Side Comparison
| Feature | Zepbound | Wegovy |
|---|---|---|
| Generic name | Tirzepatide | Semaglutide |
| Manufacturer | Eli Lilly | Novo Nordisk |
| Mechanism | GIP + GLP-1 dual agonist | GLP-1 single agonist |
| FDA indication | Chronic weight management; obstructive sleep apnea in obesity | Chronic weight management; CV risk reduction in obesity |
| Dose range | 2.5 to 15 mg weekly | 0.25 to 2.4 mg weekly |
| Frequency | Weekly SC injection | Weekly SC injection |
| Average weight loss (max dose) | ~20% body weight (SURMOUNT-1) | ~15% body weight (STEP 1) |
| Cardiovascular outcomes trial | SURMOUNT-MMO (ongoing) | SELECT (20% MACE reduction) |
| Approval year | November 2023 | June 2021 |
| Pen type | Single-dose autoinjector or multi-dose vial | Color-coded single-dose pens |
| List price/month | ~$1,060 (pens), $350–$700 (vials) | ~$1,350 |
| Boxed warning | Thyroid C-cell tumors | Thyroid C-cell tumors |
What Each One Is
Zepbound (tirzepatide) is a once-weekly subcutaneous injection that activates two incretin receptors — GIP and GLP-1. The same molecule is also marketed as Mounjaro for type 2 diabetes. Zepbound was FDA-approved in November 2023 for chronic weight management; in December 2024 it received an additional indication for obstructive sleep apnea in adults with obesity.
Wegovy (semaglutide 2.4 mg) is a once-weekly subcutaneous injection that activates the GLP-1 receptor. The same molecule is also marketed as Ozempic (lower doses for type 2 diabetes) and Rybelsus (oral). Wegovy was FDA-approved in June 2021 for chronic weight management; in 2024 it received an additional indication for cardiovascular risk reduction in obesity.
Head-to-Head Trial — SURMOUNT-5
SURMOUNT-5 (results published 2025) directly compared Zepbound to Wegovy over 72 weeks in 751 adults with obesity (without diabetes).
| Outcome | Zepbound (titrated to 10 or 15 mg) | Wegovy (titrated to 2.4 mg) |
|---|---|---|
| Average body weight loss | ~20.2% | ~13.7% |
| Patients achieving ≥ 10% loss | ~82% | ~60% |
| Patients achieving ≥ 15% loss | ~65% | ~40% |
| Patients achieving ≥ 25% loss | ~32% | ~16% |
| Trial duration | 72 weeks | 72 weeks |
Zepbound demonstrated superior weight loss across every threshold tested.
Mechanism Differences
- Both activate the GLP-1 receptor — slow gastric emptying, suppress appetite, reduce caloric intake
- Zepbound additionally activates the GIP receptor — may amplify insulin secretion, improve adipose tissue insulin sensitivity, and contribute to greater weight loss through complementary metabolic effects
- GIP activity may help offset GLP-1-induced nausea, though clinical trials show comparable GI side effect rates
Cardiovascular Outcomes
Wegovy — The SELECT trial (17,604 patients with obesity and established CVD without diabetes) showed a 20 percent reduction in major adverse cardiovascular events over 3.3 years. Wegovy carries a formal indication for cardiovascular risk reduction in adults with established CVD and overweight or obesity.
Zepbound — The SURMOUNT-MMO trial is ongoing, with results expected 2027. Cardiovascular safety appears favorable based on preliminary analyses, but cardiovascular risk reduction is not yet a labeled indication.
Other Indications and Trials
- Zepbound — FDA-approved for obstructive sleep apnea in obesity (SURMOUNT-OSA trial showed substantial reduction in apnea-hypopnea index)
- Zepbound — Studies of heart failure with preserved ejection fraction (SUMMIT) and chronic kidney disease are underway
- Wegovy — Studies in heart failure (STEP-HFpEF), Alzheimer disease (EVOKE), and chronic kidney disease (FLOW) are completed or underway, generally showing benefit
- Both molecules are being studied for non-alcoholic steatohepatitis (NASH/MASH)
When to Choose Zepbound
- Higher weight-loss target (greater than 15 percent body weight)
- Obstructive sleep apnea in the context of obesity
- Inadequate response to Wegovy at 2.4 mg
- Cash-pay patient — Zepbound vials through LillyDirect are substantially cheaper
- Insurance covers Zepbound but not Wegovy
When to Choose Wegovy
- Established cardiovascular disease — formal CV risk reduction indication based on SELECT
- Insurance covers Wegovy but not Zepbound
- Comfortable with single-dose color-coded pens
- Longer real-world experience preferred
Side Effects (Both)
- Nausea — most common; peaks after each dose increase
- Vomiting, diarrhea, constipation
- Abdominal pain, dyspepsia
- Decreased appetite
- Fatigue
- Injection site reactions
- Gallbladder issues (cholelithiasis, cholecystitis)
- Pancreatitis (rare)
- Acute kidney injury (dehydration-driven)
- Hypoglycemia when combined with insulin or sulfonylureas
- Boxed warning for thyroid C-cell tumors; contraindicated with personal/family history of medullary thyroid carcinoma or MEN 2
Dosing Schedules
Zepbound titration — 2.5 mg weeks 1–4 → 5 mg weeks 5–8 → 7.5 mg weeks 9–12 → 10 mg weeks 13–16 → 12.5 mg weeks 17–20 → 15 mg week 21+. Many patients achieve target weight loss at 5 or 10 mg and do not need maximum dose.
Wegovy titration — 0.25 mg weeks 1–4 → 0.5 mg weeks 5–8 → 1.0 mg weeks 9–12 → 1.7 mg weeks 13–16 → 2.4 mg weeks 17+.
Cost and Coverage
Zepbound is priced modestly below Wegovy. Eli Lilly also offers Zepbound vials through LillyDirect for cash-pay patients — these vials cost approximately $349 for 2.5 mg, $499 for 5 mg, $599 for 7.5 mg, and $699 for 10 mg per month, making Zepbound a notably more affordable option for the uninsured. Wegovy does not currently have an equivalent cash-pay program. Both have manufacturer copay cards for commercially insured patients.
Switching Between Them
Switching is typically straightforward — discontinue the first drug and start the other at the lowest dose the following week. Most clinicians do not skip the starting dose even if the prior drug was at maximum, to limit GI side effects. No washout period is required.
Lifestyle Pairing
Both medications work best alongside reduced-calorie diet and increased physical activity. Read more about diet strategies and obesity-related complications.
The Bottom Line
Zepbound produces greater weight loss than Wegovy in head-to-head data — about 20 percent versus 14 percent body weight reduction over 72 weeks. Wegovy has stronger cardiovascular outcome data and a formal cardiovascular risk reduction indication. Side effect profiles are similar. Zepbound is somewhat cheaper at list price and substantially cheaper for cash-pay patients through LillyDirect vials. Talk to your doctor about which fits your goals — weight loss, cardiovascular risk reduction, cost, or insurance coverage are all reasonable bases for the choice.
