Mounjaro vs Zepbound: The Same Tirzepatide, Two Labels, Two Prices

Yes, Zepbound and Mounjaro contain the same active ingredient, tirzepatide. The FDA said so when it approved Zepbound on November 8, 2023: tirzepatide was already approved as Mounjaro to improve blood sugar in adults with type 2 diabetes.4 The Zepbound label states it plainly: "ZEPBOUND contains tirzepatide."2

Tirzepatide acts on two hormone receptors, GIP and GLP-1. It lowers appetite and food intake, and it helps the body release insulin.1,2 Both labels carry the same boxed warning about thyroid C-cell tumors in rats, and both are off limits for people with a personal or family history of medullary thyroid cancer or MEN 2.1,2

Because they are one drug, you should never take both. The Zepbound label does not recommend using it with any other tirzepatide product or any GLP-1 drug.2

Mounjaro is the same drug as Zepbound, approved first and for a different job. The FDA first approved Mounjaro on May 13, 2022.3 Its label lists two uses:1

• to improve blood sugar, with diet and exercise, in adults and children 10 and older with type 2 diabetes;
• to lower the risk of heart attack, stroke and heart-related death in adults with type 2 diabetes who are at high risk.

Weight loss is not one of Mounjaro's approved uses.1 For that, Lilly sells Zepbound. Our guide to what Zepbound is covers how tirzepatide works and who it suits.

The difference between Mounjaro and Zepbound is the approved use, the dosing rules that follow from it, and the price. The drug, the strengths and the pens are the same.

Zepbound is approved, with diet and exercise, for adults with obesity, or with overweight plus at least one weight-related condition.2 On December 20, 2024, the FDA also approved it for moderate to severe obstructive sleep apnea in adults with obesity. The FDA called it the first drug treatment option for certain patients with sleep apnea.5 Our article on Zepbound for sleep apnea covers that approval and its coverage.

Mounjaro has no weight or sleep apnea approval, and Zepbound has no diabetes or children's approval.1,2

Both start at 2.5 mg once a week for 4 weeks, and both rise in 2.5 mg steps after at least 4 weeks on a dose.1,2 The goal of each step differs. On Mounjaro, the dose goes up if more blood sugar control is needed.1 On Zepbound, the label sets a maintenance dose of 5 mg, 10 mg or 15 mg for weight loss, and 10 mg or 15 mg for sleep apnea.2 Our tirzepatide dosing guide sets out each step for both.

Both come as single-dose pens or vials holding one dose in 0.5 mL, and as a multi-dose vial or KwikPen that holds four weekly doses.1,2 The rules for missed doses are the same: take it within 4 days, or skip it.1,2 For the injection steps, see how to inject Mounjaro.

Zepbound is the one approved for weight loss, but both drugs lower weight, because they are the same molecule. The trials behind each label measured different things.

In SURMOUNT-1, a 72-week trial in adults with obesity and no diabetes, Zepbound lowered body weight by 15.0% at 5 mg, 19.5% at 10 mg and 20.9% at 15 mg, against 3.1% on placebo.2 In SURMOUNT-2, in adults with type 2 diabetes, it lowered weight by 12.8% at 10 mg and 14.7% at 15 mg, against 3.2% on placebo.2 Both results count everyone who started the trial (treatment-policy estimand).2

The Mounjaro trials aimed at blood sugar, and they recorded weight as well. In SURPASS-2, a 40-week trial in 1,879 adults with type 2 diabetes on metformin, Mounjaro 15 mg lowered A1C by 2.3 points and weight by 11.2 kg. Semaglutide 1 mg lowered A1C by 1.9 points and weight by 5.7 kg (treatment-policy estimand).1 For the full weight results, see Zepbound weight loss results. For tirzepatide against semaglutide in people without diabetes, see semaglutide vs tirzepatide.

Yes, the side effects are the same kind, because the drug is the same. Each label reports them from its own trials. In the Zepbound weight-loss trials, nausea hit 25% to 29% of patients against 8% on placebo, and diarrhea 19% to 23% against 8%.2 Most nausea, vomiting and diarrhea came during the dose increases and eased over time, on both labels.1,2

Both labels warn about pancreatitis, gallbladder problems, low blood sugar with insulin or sulfonylureas, and kidney injury from dehydration.1,2 Both say birth control pills may work less well for 4 weeks after starting and after each dose increase.1,2 If you have side effects, talk to your provider. Each drug has its own guide: Mounjaro side effects and Zepbound side effects.

The two cost different amounts mostly because of how they are covered. Lilly's own prices, read on October 25, 2026, are below.

With commercial insurance that covers the drug, both savings cards bring the price down to as little as $25 for up to a 3-month prescription.6,7 The Mounjaro card saves up to $150 a month and $1,950 a year.7 The Zepbound card saves up to $100 a month and $1,300 a year.6 Both cards end on December 31, 2026.6,7

With commercial insurance that does not cover the drug, both cards bring a single-dose pen down to as low as $499 for a month.6,7

Without insurance, Lilly sells Zepbound self-pay as a KwikPen or vials, not as the single-dose pen. It costs $299 a month for 2.5 mg and $399 for 5 mg.6 The higher doses cost $449 on the first purchase, and stay at $449 if you refill within 45 days. Otherwise they cost $499 for 7.5 mg and $699 for 10 mg to 15 mg.6 Lilly's Mounjaro page lists no self-pay price.7 For the ways to buy, see how to get Zepbound and the Zepbound savings card.

Insurance covers Mounjaro and Zepbound for their approved uses, and those uses differ. A plan that covers diabetes drugs may cover Mounjaro for type 2 diabetes. Zepbound for weight loss depends on whether your plan covers weight-loss drugs. That is why Lilly lists a separate price for people whose plan does not cover Zepbound.6

Medicare. Lilly says about 8 in 10 people with Medicare Part D pay "between $0-$50 for a 28-day supply of Mounjaro", based on IQVIA data from October 2024 to September 2025.7 For weight loss, the Medicare GLP-1 Bridge has covered Zepbound since July 1, 2026, for a $50 copay a month. It covers the KwikPen only, not single-dose vials or pens, and it does not cover Mounjaro.8 You need a BMI of 35 or more, or a lower BMI with certain conditions.8 People with type 2 diabetes or moderate to severe sleep apnea are not eligible for the Bridge, but their Part D plan may still cover a GLP-1 for those conditions.8 Our guides to what insurance covers Zepbound and Medicare GLP-1 coverage go further.

Switching between the two is a prescribing decision, because only the label differs, not the drug. Your provider writes a prescription for the one that fits your diagnosis: Mounjaro for type 2 diabetes, Zepbound for weight loss or sleep apnea.1,2 The labels give no separate plan for moving from one to the other. Both start at 2.5 mg and use the same strengths, so ask your provider what dose to continue on.1,2

Compounded tirzepatide is not Mounjaro or Zepbound. It is not FDA-approved: the FDA doesn't review its safety, effectiveness or quality before it's sold.9

The bigger question with any compounded program is the drug itself. Compounded GLP-1s are prepared by a pharmacy to a prescription. They are not FDA-approved: the FDA doesn't review their safety, effectiveness or quality before they're sold, and they are not the same as Wegovy or Zepbound.9 Formulas can differ from one pharmacy to the next, and some add ingredients such as vitamin B12.10,11 Compounding pharmacies are licensed and inspected by state boards of pharmacy; outsourcing facilities (503B) also register with the FDA and are inspected by it. The FDA can issue warning letters when either breaks rules on safety or sterility.9

Our compounded tirzepatide guide explains the rules.

Is Zepbound stronger than Mounjaro? No. Both come in the same strengths, from 2.5 mg to 15 mg, and 15 mg is the highest adult dose of each.1,2

Can I take Mounjaro for weight loss without diabetes? Mounjaro is approved only for type 2 diabetes and heart risk in type 2 diabetes.1 The tirzepatide product approved for weight loss is Zepbound.2

Can people with type 2 diabetes take Zepbound? Zepbound's weight-loss approval does not exclude them, and SURMOUNT-2 tested it in adults with type 2 diabetes.2 The label advises considering a lower dose of insulin or sulfonylureas when starting it.2

Why are there two names for one drug? Lilly sells tirzepatide as Mounjaro for type 2 diabetes and as Zepbound for weight loss and sleep apnea.4,5 Each name carries its own label, uses, savings card and price.1,2,6,7

If your goal is weight loss, Zepbound is the tirzepatide approved for it. Compare what online programs charge in our cheapest Zepbound ranking.

This article is for information only and is not medical advice. Compounded drugs are not FDA-approved. Talk to a licensed clinician before starting or switching any GLP-1 treatment.