Mounjaro vs Wegovy: Weight Loss Compared

Mounjaro vs Wegovy comes down to two different molecules with two different jobs. Mounjaro is tirzepatide, a dual GLP-1/GIP drug from Eli Lilly that is FDA-approved for type 2 diabetes and used off-label for weight. Wegovy is semaglutide, a GLP-1 drug from Novo Nordisk that is FDA-approved for weight management. In head-to-head data the Mounjaro molecule tends to produce more weight loss, but Wegovy is the one actually licensed for weight, and the cleaner on-label tirzepatide option for weight is Zepbound.

People search for these two brand names side by side because they hear about both as "weight loss shots." The important nuance is that they are not the same class of drug, and only one of them is technically approved for the job most searchers care about. This guide walks through what each drug is, how much weight each produces, dosing, side effects, and price, so you can have a clearer conversation with a clinician.

One reason the comparison gets confusing is that the same molecule can appear under two brand names. Eli Lilly sells tirzepatide as Mounjaro for diabetes and as Zepbound for weight, and Novo Nordisk sells semaglutide as Ozempic for diabetes and as Wegovy for weight. So when you line up Mounjaro against Wegovy, you are comparing a diabetes brand against a weight brand, even though the underlying weight-loss potential of each molecule is what most people actually want to know about.

What Mounjaro and Wegovy actually are

Mounjaro is the brand name for tirzepatide, made by Eli Lilly. It is a once-weekly injection and it acts on two gut-hormone receptors at once: GLP-1 and GIP. That dual action is why many people group it separately from single-hormone drugs. Mounjaro is FDA-approved for type 2 diabetes. When people use Mounjaro purely for weight loss, they are using it off-label, because Lilly markets the same tirzepatide molecule for weight under a different brand, Zepbound. If you want to understand the mechanism, see how tirzepatide works.

Wegovy is the brand name for semaglutide, made by Novo Nordisk. It is also a once-weekly injection, but it is a single GLP-1 receptor agonist. Wegovy is FDA-approved specifically for chronic weight management in adults and adolescents who meet the criteria. So Wegovy is on-label for weight, while Mounjaro is on-label for diabetes.

Put plainly, this comparison is really tirzepatide (sold as a diabetes brand) versus semaglutide (sold as a weight brand). For a deeper look at the underlying molecules rather than the brand names, see semaglutide vs tirzepatide.

Mounjaro vs Wegovy at a glance

Feature	Mounjaro	Wegovy
Active ingredient	Tirzepatide	Semaglutide
Drug class	Dual GLP-1/GIP receptor agonist	GLP-1 receptor agonist
FDA-approved use	Type 2 diabetes (weight is off-label)	Chronic weight management
Weight loss	About 20.9% average total body weight (SURMOUNT-1)	About 14.9% average total body weight (STEP-1)
Max dose	15 mg weekly	2.4 mg weekly
List price per month	About $1,069	About $1,349 (NovoCare cash option around $499 for eligible self-pay patients)
Weight-approved twin	Zepbound (same tirzepatide)	Wegovy is already the weight brand

Weight loss: how the two compare

The headline trial numbers favor the Mounjaro molecule. In SURMOUNT-1, tirzepatide reached roughly 20.9% average total body-weight loss at the top dose. In STEP-1, semaglutide reached about 14.9%. Those were separate trials with different populations, so cross-trial numbers only tell you so much.

The cleaner evidence comes from SURMOUNT-5, a direct head-to-head trial that pitted tirzepatide against semaglutide in the same study. Tirzepatide came out ahead, with weight loss around 20% versus roughly 14% for semaglutide. In short, the tirzepatide molecule inside Mounjaro generally produces more weight loss than the semaglutide molecule inside Wegovy. For a broader breakdown of what each drug delivers, see GLP-1 weight loss results by drug.

Individual results vary widely. Trial averages are not promises, and factors like dose tolerance, adherence, diet, and activity all shape the outcome you personally get. Some people respond strongly to one drug and modestly to the other, and a person who cannot tolerate the higher doses of one may end up losing less than the average suggests. The trial figures describe what happened across large groups over many months, not what any single person should expect week to week.

It also helps to remember that these numbers reflect the top tolerated doses studied under trial conditions, with structured support and monitoring. Real-world weight loss is often somewhat lower, because adherence slips, doses get held for side effects, and lifestyle support varies. The relative ranking tends to hold up even so, with tirzepatide generally leading, but the absolute percentages are best treated as a ceiling rather than a target.

Dosing schedules

Both drugs start low and step up slowly to reduce side effects. Mounjaro begins at 2.5 mg weekly and can be titrated upward to a maximum of 15 mg weekly, moving through intermediate doses as tolerated. Wegovy begins at 0.25 mg weekly and titrates up to a maintenance dose of 2.4 mg weekly, which is also its maximum. The milligram numbers are not comparable between the two drugs because they are different molecules with different potencies, so a bigger number does not mean a bigger dose in any meaningful sense.

Side effects and safety

Because both are GLP-1 class drugs, their side-effect profiles overlap heavily. The most common issues are gastrointestinal: nausea, diarrhea, vomiting, and constipation. These tend to be concentrated early in treatment and during each dose increase, then often ease as the body adjusts. Slow titration exists largely to blunt these effects.

Both drugs also carry the same boxed warning about thyroid C-cell tumors, based on rodent studies, and both are generally avoided in people with a personal or family history of medullary thyroid carcinoma or MEN 2. For brand-specific detail, see Mounjaro side effects and Wegovy side effects. Any warning signs should be discussed promptly with a prescriber.

Beyond the common gastrointestinal complaints, both drugs share a set of less frequent but more serious considerations that a prescriber will screen for, including pancreatitis, gallbladder problems, and low blood sugar when combined with certain other medicines. Because tirzepatide acts on an additional receptor, some people wonder whether its side-effect profile differs meaningfully, but in practice the tolerability issues that matter day to day are similar for both drugs and are dominated by the same nausea and bowel symptoms. Staying hydrated, eating smaller meals, and moving up doses slowly are the usual practical steps, and none of that replaces individualized medical advice.

Cost and coverage

At list price, Mounjaro runs about $1,069 a month and Wegovy about $1,349 a month. Novo Nordisk offers a NovoCare cash option around $499 a month for eligible self-pay patients, which can narrow the gap. Insurance coverage tends to be easier to obtain for Mounjaro, largely because it is approved for diabetes, and many plans cover diabetes drugs more readily than weight drugs. What you actually pay depends heavily on your specific plan, so it is worth checking. For a wider view of pricing, see the GLP-1 cost index 2026.

Is Mounjaro better than Wegovy?

On raw weight-loss efficacy, the tirzepatide in Mounjaro tends to win. But "better" depends on the question. Wegovy is on-label for weight, which can matter for prescribing and coverage, while Mounjaro is on-label for diabetes and only used off-label for weight. If weight loss is your actual goal and you want an on-label tirzepatide option, the more direct choice is Zepbound rather than Mounjaro. Useful related comparisons include Ozempic vs Mounjaro, Wegovy vs Zepbound, and Mounjaro vs Zepbound.