Zepbound vs Wegovy: Weight Loss, Side Effects, Doses and 2026 Cash Price

Zepbound (tirzepatide) produced more weight loss than Wegovy (semaglutide) in the only head-to-head trial: 20.2% vs. 13.7% of body weight at 72 weeks in SURMOUNT-5¹. Both are once-weekly shots with similar stomach side effects. Paying cash, Wegovy pens cost $349 a month after a $199 intro offer, and Zepbound $299 to $449 by dose.

That's the short version. The longer one matters, because the right pick depends on more than the average result: how each drug is dosed, which side effects you can live with, what your insurance or Medicare will pay for, and what you'll spend once you reach a maintenance dose. Each of those is covered below, with the source for every number.

Which loses more weight, Zepbound or Wegovy?

Zepbound, on average. SURMOUNT-5 randomized 751 adults with obesity but without type 2 diabetes to the highest dose each person could tolerate of either tirzepatide (10 or 15 mg) or semaglutide (1.7 or 2.4 mg), once weekly for 72 weeks. Average weight change was −20.2% with tirzepatide and −13.7% with semaglutide. Waist circumference fell 18.4 cm vs. 13.0 cm, and people on tirzepatide were more likely to reach 10%, 15%, 20% and 25% weight loss¹. The trial was open-label and funded by Eli Lilly, which makes Zepbound¹.

The earlier placebo-controlled trials point the same way, though they were run separately and can't be compared directly:

An average is not a promise. In STEP 1, about half the people on semaglutide lost 15% or more of their weight²; in SURMOUNT-1, 57% of people on the 15 mg dose lost 20% or more³. Plenty of people do well on either drug, and some respond better to one than the other. For the molecule-level comparison, including how GIP adds to GLP-1 action, see semaglutide vs. tirzepatide.

How do the doses compare?

Both are once-weekly injections that start low and step up every four weeks, so your stomach has time to adjust. The labels set the schedule:

Wegovy's label sets 2.4 mg as the usual maintenance dose and allows 7.2 mg weekly for weight reduction in people who have tolerated 2.4 mg for at least four weeks⁴. Zepbound's label starts at 2.5 mg for four weeks and raises it in 2.5 mg steps every four weeks, with 5, 10 or 15 mg as the maintenance dose and 15 mg as the maximum⁵. Your clinician may hold you at a dose longer if side effects are hard to manage. For the full week-by-week detail, see the GLP-1 dosing and titration schedule.

Which has more side effects?

They're similar in kind. Both labels list nausea, diarrhea, vomiting, constipation, abdominal pain and indigestion among the most common side effects^4,5. In SURMOUNT-5, the most common adverse events in both groups were gastrointestinal, mostly mild to moderate, and happened mainly while the dose was being raised¹.

The trials report dropout from side effects differently, so the numbers below aren't a clean comparison. In STEP 1, 4.5% of people on semaglutide stopped because of stomach side effects, vs. 0.8% on placebo². In SURMOUNT-1, side effects of any kind led 4.3%, 7.1% and 6.2% of people on 5, 10 and 15 mg of tirzepatide to stop, vs. 2.6% on placebo³.

Both carry the same boxed warning about thyroid C-cell tumors seen in rodents, and neither should be used by anyone with a personal or family history of medullary thyroid carcinoma or MEN 2^4,5. Our guide to GLP-1 side effects and how to manage them covers what helps in the first weeks.

What else are they approved for?

This matters for insurance. Wegovy is approved for weight reduction, for lowering the risk of major cardiovascular events in adults with established heart disease and obesity or overweight, and for a form of fatty liver disease (MASH with moderate to advanced fibrosis)⁴. Zepbound is approved for weight reduction and for moderate to severe obstructive sleep apnea in adults with obesity⁵. If one of those other conditions applies to you, your plan may cover one drug and not the other.

What does each cost without insurance in 2026?

Both makers sell directly to cash-paying patients, and TrumpRx.gov lists the same starting prices⁹. The catch is that the headline prices are starting-dose prices.

Lilly prices Zepbound per 28-day fill⁷, so a year at a maintenance dose is 13 fills: 13 × $449 = $5,837. A year of Wegovy at $349 a month is $4,188. That gap narrows if you hold Zepbound at 5 mg ($399), and widens if a refill slips past 45 days. Our LillyDirect Zepbound price guide breaks down the vial and KwikPen prices by dose.

Compounded semaglutide and tirzepatide aren't FDA-approved products, and they cost less partly for that reason; the compounded medians above come from our price index, and most of those plans include the prescriber. For the full picture, see semaglutide cost without insurance, tirzepatide cost without insurance and the TrumpRx price guide.

Is the Wegovy pill an option instead?

For people who'd rather not inject, yes. The Wegovy pill is the same molecule, taken once daily: it starts at 1.5 mg for 30 days, then 4 mg, then 9 mg, with 25 mg daily as the maintenance dose⁴. Its self-pay price starts at $149 a month and reaches $299 at the 9 mg and 25 mg doses⁶. There's no oral tirzepatide. If a pill is what you want, see injections vs. oral GLP-1s and the oral GLP-1 board.

Which one does Medicare GLP-1 Bridge cover?

Both, with a catch for Zepbound. Medicare GLP-1 Bridge covers Wegovy (injection or tablet), Foundayo and the Zepbound KwikPen for $50 a month for eligible people with Part D coverage. Zepbound vials and the single-dose Zepbound pen are not covered⁸. If you're on Medicare, ask your prescriber to write for the KwikPen if you choose Zepbound. Our guide to Medicare GLP-1 Bridge explains who qualifies.

Can you switch between them?

Yes. People switch for cost, side effects or a plateau, and the usual direction is from semaglutide to tirzepatide. There's no fixed conversion between the two drugs; a switch is a clinical decision about which tirzepatide dose to start on, made by your prescriber. Zepbound's label starts every new patient at 2.5 mg⁵. See switching from semaglutide to tirzepatide for what to ask.

How to choose

If the most weight loss is your priority and the cost works, Zepbound has the stronger head-to-head result¹. If you want a pill option, a cardiovascular or fatty-liver indication your insurer recognizes, or a lower maintenance price on brand-name medication, Wegovy may fit better. If you're on Medicare, either can work through the Bridge, but only as the Zepbound KwikPen⁸. If brand-name prices are out of reach, compounded versions of both molecules are sold through telehealth at lower monthly prices.

To compare programs, the tirzepatide board and the semaglutide board list telehealth plans with their month-to-month prices; the brand-name board lists the programs that prescribe Wegovy and Zepbound themselves. Sesame Care (Partner) prescribes both brand-name drugs, with the medication billed at cash-pay rates on top of a care subscription. If you're still unsure, the 2-minute quiz weighs your budget, medication preference and insurance and shows the programs that fit.