Zepbound or Wegovy. Same goal, different drug.
Zepbound is tirzepatide. Wegovy is semaglutide. Both are FDA-approved weekly injections for chronic weight management. Both work. They do not work equally well, they do not cost the same, and they do not feel the same on the body. In May 2025 the SURMOUNT-5 trial put them head-to-head for 72 weeks, and the result decided the debate for most people.
🔑 Key Takeaways
- Zepbound (tirzepatide) beat Wegovy (semaglutide) head-to-head in SURMOUNT-5, producing roughly 47% more weight loss over 72 weeks.
- Zepbound hits two hormone receptors (GLP-1 and GIP). Wegovy hits one (GLP-1 only). That is the mechanism reason behind the efficacy gap.
- Zepbound is also the only drug FDA-approved for obstructive sleep apnea in adults with obesity. Wegovy is not.
- Wegovy has a longer safety record, a pediatric indication from age 12, and cardiovascular outcome data (SELECT trial) that Zepbound does not yet have.
- List price is close. Real out-of-pocket depends entirely on your insurance. Zepbound is slightly cheaper at retail in 2026.
Here is the full side-by-side, using the actual trial data, pricing in 2026, and the honest trade-offs most articles skip.
The 30-second answer
If you only care about how much weight you will lose, and nothing else matters, Zepbound wins. SURMOUNT-5 showed about 20.2% body weight loss at 72 weeks on tirzepatide vs 13.7% on semaglutide. That is roughly 50 lbs vs 34 lbs for a 250 lb starting weight.
If you have heart disease, a history of stroke, or your doctor wants a drug with long-term cardiovascular outcome data on record, Wegovy has the edge. The SELECT trial showed a 20% reduction in major cardiovascular events on semaglutide. Tirzepatide does not have equivalent outcome data yet, although the SURMOUNT-MMO trial is reading out in 2026.
For most adults with obesity and no heart history, Zepbound is the stronger choice on paper.
Side-by-side specs
| Zepbound | Wegovy | |
|---|---|---|
| Active drug | Tirzepatide | Semaglutide |
| Mechanism | Dual GLP-1 + GIP agonist | GLP-1 agonist |
| Maker | Eli Lilly | Novo Nordisk |
| FDA approved | November 2023 (weight), Dec 2024 (OSA) | June 2021 |
| Dose range | 2.5 to 15 mg weekly | 0.25 to 7.2 mg weekly |
| Max weight loss in trials | ~20-22.5% body weight | ~15-17% body weight |
| Age range | Adults (18+) | Age 12 and up |
| Additional indications | Obstructive sleep apnea | Cardiovascular risk reduction, pediatric obesity |
| List price (2026) | ~$1,060/month | ~$1,350/month |
| Lilly/Novo direct price | ~$349-$499/month (vials) | ~$499/month (pens) |
What SURMOUNT-5 actually showed
This is the head-to-head trial the comparison hinges on.
SURMOUNT-5 was published in the New England Journal of Medicine in May 2025. It ran 72 weeks, enrolled 751 adults with obesity but without diabetes, and randomized them to maximum-tolerated tirzepatide or maximum-tolerated semaglutide. No blinding, both groups got the same lifestyle counseling.
| Outcome at 72 weeks | Zepbound (tirzepatide) | Wegovy (semaglutide) |
|---|---|---|
| Mean body weight change | -20.2% | -13.7% |
| Avg weight lost (lbs) | -50.3 lbs | -33.1 lbs |
| Reached 15% weight loss | 64.6% | 40.1% |
| Reached 20% weight loss | 48.4% | 27.3% |
| Reached 25% weight loss | 31.6% | 16.1% |
| Waist circumference change | -7.2 inches | -5.1 inches |
The punchline: Zepbound roughly doubled the share of patients who hit the 25% weight-loss threshold. That is the threshold where body composition, joint load, and OSA risk all change meaningfully.
For the deeper mechanism breakdown, see tirzepatide vs semaglutide and how GLP-1 works.
Mechanism: why Zepbound pulls ahead
One drug hits one receptor. The other hits two.
Semaglutide activates only the GLP-1 receptor, which suppresses appetite, slows gastric emptying, and improves insulin response. Tirzepatide activates GLP-1 plus the GIP receptor. GIP does two extra things: it enhances the appetite-suppressing effect of GLP-1, and it appears to improve how fat cells handle energy, which shows up as more efficient fat loss and preserved lean mass at similar caloric deficits.
That combined action is why tirzepatide consistently outperforms semaglutide in head-to-head data, not because the doses are higher.
The successor already exists
Retatrutide, still in phase 3 trials, adds a third receptor (glucagon) on top of GLP-1 and GIP. Early phase 2 data showed up to 24% weight loss at 48 weeks, higher than tirzepatide at 72 weeks. If efficacy is the only thing you care about, see the retatrutide vs tirzepatide comparison before committing to a long-term protocol.
Side effects: more similar than different
Both drugs cause gut symptoms. Both cause them to roughly the same degree.
| Side effect | Zepbound | Wegovy |
|---|---|---|
| Nausea | 31-44% | 44% |
| Diarrhea | 20-23% | 30% |
| Vomiting | 10-15% | 24% |
| Constipation | 17% | 24% |
| Discontinuation due to side effects | ~6% | ~6-7% |
| Serious adverse events | Similar | Similar |
Wegovy tends to produce slightly more vomiting and diarrhea at peak doses. Zepbound tends to produce more constipation. Neither difference is large enough to drive a prescribing decision by itself.
See the full tirzepatide side effects guide and semaglutide side effects guide for management protocols.
Cost in 2026
Close on paper. Different in practice.
List price for both drugs is in the $1,000 to $1,400 range per month. But almost nobody pays list price. The real number depends on four things: your insurance, your state, whether you use the manufacturer direct program, and whether you buy branded pens or single-dose vials.
| Purchase route | Zepbound | Wegovy |
|---|---|---|
| Retail list price | ~$1,060/mo | ~$1,350/mo |
| Commercial insurance w/ coverage | $25-$100/mo copay | $25-$100/mo copay |
| Manufacturer direct (vials or pens) | $349-$499/mo | $499/mo |
| Manufacturer savings card | As low as $25/mo | As low as $0-$25/mo |
| Medicare Part D | Covered only for OSA | Covered for CV risk reduction |
For the full cost breakdown, see tirzepatide cost guide, ozempic cost, and GLP-1 without insurance.
Sleep apnea: Zepbound has a second indication Wegovy does not
This matters for a real chunk of the market.
In December 2024 Zepbound became the first and only FDA-approved drug for obstructive sleep apnea in adults with obesity, based on the SURMOUNT-OSA trial. Wegovy does not have this indication. If you carry an OSA diagnosis along with obesity, your insurer is more likely to cover Zepbound because of the dual indication.
See the full sleep apnea treatment guide for the trial data and dosing protocol.
Heart disease: Wegovy has the outcome data Zepbound does not (yet)
This is the one area Wegovy clearly wins.
The SELECT trial, published in 2023, followed 17,600 adults with overweight or obesity and established cardiovascular disease for an average of 3.3 years on semaglutide. It showed a 20% reduction in the risk of major cardiovascular events (heart attack, stroke, CV death). Wegovy was subsequently approved for cardiovascular risk reduction. Tirzepatide has a similar trial (SURMOUNT-MMO) but results are not yet published in 2026.
If you or your doctor are prioritizing proven heart-disease outcomes, Wegovy is currently the safer evidence-backed bet.
Dosing schedules compared
Very different ramp-up speeds.
| Month | Zepbound | Wegovy |
|---|---|---|
| Month 1 | 2.5 mg weekly | 0.25 mg weekly |
| Month 2 | 5 mg weekly | 0.5 mg weekly |
| Month 3 | 7.5 mg weekly | 1.0 mg weekly |
| Month 4 | 10 mg weekly | 1.7 mg weekly |
| Month 5+ | 12.5 or 15 mg weekly | 2.4 mg weekly |
| Max dose (2025 update) | 15 mg weekly | 7.2 mg weekly |
Both drugs take roughly 4 to 5 months of titration to reach a maintenance dose. Wegovy's 7.2 mg expanded dose (approved 2025) closed some of the efficacy gap, but SURMOUNT-5 was run before that dose was available, so current head-to-head data uses the older max.
Full schedules: tirzepatide dosing guide and semaglutide dosing guide.
When Wegovy is the better pick
- You have established heart disease or have had a cardiovascular event. SELECT trial data is real and Zepbound does not yet have a published equivalent.
- You are treating obesity in a child age 12 to 17. Wegovy has the pediatric approval. Zepbound does not.
- You tolerate GLP-1s well and got great results on Ozempic in the past. You already know the drug works for you.
- Your insurance covers Wegovy but not Zepbound. Plenty of plans still cover only one.
When Zepbound is the better pick
- Weight loss is the primary goal and you want the biggest drop. 47% more weight loss in head-to-head.
- You have moderate-to-severe obstructive sleep apnea plus obesity. Only Zepbound has the OSA label.
- You have already tried semaglutide and plateaued. Switching to tirzepatide is a standard playbook: see switching from semaglutide to tirzepatide.
- You want the lower retail price with the manufacturer direct vial program.
What happens when you stop either drug
The weight comes back. On both.
STEP-4 showed that people who stopped semaglutide after 68 weeks regained roughly two-thirds of the weight they lost within a year. SURMOUNT-4 showed a similar pattern with tirzepatide, with about half the lost weight returning after discontinuation. There is no meaningful difference between the two drugs here: if you stop, weight regain is the default.
That is why both are framed as chronic weight-management drugs, not a short course. Long-term use, tapering to a maintenance dose, or transitioning to another protocol is the pattern most obesity specialists follow in 2026.