6 Things to Know When Comparing Mounjaro vs. Zepbound
Key takeaways:
Mounjaro and Zepbound are once-weekly injections that contain the same active ingredient: tirzepatide. Both brand names share similar dosages, side effects, and drug interactions.
Mounjaro is FDA approved for Type 2 diabetes in adults. Zepbound is approved for chronic weight management and obstructive sleep apnea in certain adults. Both forms of tirzepatide work best when combined with lifestyle changes.
There are ways to save on Mounjaro and Zepbound. If you’re eligible, a manufacturer savings card could help you get either for as little as $25 per prescription.
Table of contents
It’s not unusual for a medication to have more than one brand name. Many times, this happens when a medication has multiple uses. One example is Mounjaro and Zepbound — two brand names for tirzepatide.
Tirzepatide was originally studied for the treatment of Type 2 diabetes. But during clinical trials, researchers discovered that it caused significant weight loss for many people. And since then, scientists have discovered more uses for tirzepatide, such as obstructive sleep apnea (OSA). This led to the FDA approving tirzepatide for Type 2 diabetes, weight loss, and OSA.
So if both Mounjaro and Zepbound contain tirzepatide, does that mean you can use them interchangeably? Not exactly. Below, we’ll review six things to consider when comparing the two brand names of tirzepatide.
Good to know: The manufacturer of Mounjaro and Zepbound has a barcode scanning tool online to help you verify that the medication you're taking is legitimate. Using your phone's or computer's camera, scan the barcode on your product. The tool will tell you if you have authenticate Mounjaro or Zepbound.
1. Both Mounjaro and Zepbound contain the active ingredient tirzepatide
Mounjaro and Zepbound are both injections that contain the same active ingredient: tirzepatide. This means they both work the same way in the body.
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Tirzepatide is the first in a new class of medications: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonists. Tirzepatide works by mimicking GIP and GLP-1 (two gut hormones in the body).
After injecting a dose, tirzepatide has several effects on the body:
Signals your pancreas to release insulin after you eat
Helps glucose (sugar) move from your bloodstream into your cells, lowering blood sugar levels
Decreases the amount of new sugar your liver makes
Slows the passage of food through your digestive tract, helping you to feel full longer
Sends signals to your brain that help regulate your appetite
Helps balance levels of hunger hormones in the brain, helping you to feel less hungry
May help lower levels of certain inflammatory chemicals that play a role in OSA
2. Mounjaro is approved for Type 2 diabetes, while Zepbound is approved for weight loss and sleep apnea
Given that both medications contain tirzepatide, does that mean Zepbound is just another name for Mounjaro? No. Each medication has different FDA-approved uses. This distinction can make a difference when it comes to insurance coverage (more on this later).
Mounjaro is approved to help lower blood sugar levels in adults living with Type 2 diabetes. It should be combined with a diabetes-friendly diet and regular exercise.
Zepbound is approved for chronic weight management for adults who are considered obese, or who are considered overweight with at least one weight-related health condition. It’s also approved to treat moderate-to-severe OSA for adults who are considered obese. For both uses, you should combine Zepbound with a low-calorie diet and routine exercise.
Good to know: Neither Mounjaro nor Zepbound have a generic version available yet. If you see someone selling “generic tirzepatide” or “compounded tirzepatide,” these aren’t the same as Mounjaro or Zepbound. These products also haven’t been evaluated by the FDA for safety or effectiveness.
3. Mounjaro and Zepbound are both injected once a week
There are many similarities when it comes to Mounjaro and Zepbound dosages. Both medications are injected once a week. And you can choose to inject doses under the skin in the stomach, thigh, or upper arm. Rotate the areas you use to help prevent irritation.
How does tirzepatide work? Pharmacists explain the science behind how Mounjaro’s and Zepbound’s active ingredient, tirzepatide, works.
What taking Mounjaro feels like: Real people share their experiences with Mounjaro, a medication that’s proven effective at treating Type 2 diabetes.
Possible side effects: Read about tirzepatide’s potential side effects — from diarrhea to hair loss — and how to manage them.
Mounjaro and Zepbound both come as pre-filled, single-dose injector pens. They’re also available in the same doses:
2.5 mg/0.5 mL
5 mg/0.5 mL
7.5 mg/0.5 mL
10 mg/0.5 mL
12.5 mg/0.5 mL
15 mg/0.5 mL
For Mounjaro, you can also get all six doses in single-dose vials. With Zepbound, only certain doses are available in vials. As of February 2025, Zepbound vials are available in 2.5 mg, 5 mg, 7.5 mg, and 10 mg doses.
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With both Mounjaro and Zepbound, you’ll start with the lowest dose for a few weeks. This dose may not provide any blood sugar-lowering, weight-loss, or OSA-related effects. It’s intended to help your body adjust to the medication and limit side effects.
Over a period of several weeks, your prescriber will slowly raise your dose until you have an ideal response without too many side effects. For Mounjaro, an ideal response could mean lowering your hemoglobin A1C (HbA1c or A1C) — your average blood sugar over the past 2 to 3 months. For Zepbound, this might be a certain amount of weight loss or OSA symptom reduction. The maximum recommended dosage for both Mounjaro and Zepbound is 15 mg once a week.
4. Mounjaro and Zepbound share similar side effects
Since Mounjaro and Zepbound both contain tirzepatide, they have similar side effects. Common side effects include:
Nausea and vomiting
Diarrhea or constipation
Heartburn
Stomach pain
Low appetite
Burping
Gas (flatulence)
For many people, these side effects are mild and improve or go away after their body adjusts to the medication. Following the recommended dosage schedule for Mounjaro or Zepbound helps limit these side effects. Lifestyle and dietary changes can also go a long way when it comes to side effect management.
More serious side effects have also been reported, but they’re generally rare. These include:
Low blood sugar (hypoglycemia)
Pancreatitis (swelling of the pancreas)
Gallbladder disease, including gallstones
Acute (sudden) kidney damage
Severe gastrointestinal problems
Temporary worsening of diabetic retinopathy (an eye problem caused by diabetes)
Animal studies have found that rats receiving tirzepatide developed thyroid C-cell tumors. But research of humans has not found the same link. To be safe, it’s recommended to avoid Mounjaro and Zepbound if you have a personal or family history of medullary thyroid cancer or if you have a personal history of multiple endocrine neoplasia syndrome type 2.
Discuss your risk for serious side effects with your medical care team before starting Mounjaro or Zepbound.
5. Mounjaro and Zepbound have similar drug interactions
As with side effects, Mounjaro and Zepbound share similar drug interactions. Sharing a complete medication list with your medical care team (including your pharmacist) can help them pinpoint and manage potential interactions.
On their own, Mounjaro and Zepbound are unlikely to cause low blood sugar. But this risk goes up when they’re combined with other medications that affect insulin release in the body. Examples include insulin, sulfonylureas like glipizide (Glucotrol XL), and glinides like repaglinide. Your diabetes care team may lower the dose of one or more of your medications to help prevent low blood sugar.
As discussed earlier, Mounjaro and Zepbound slow the passage of food through the digestive tract. They may also slow the passage of oral medications. In some cases, this could affect how your body absorbs them. For example, your body may absorb less medication from oral birth control pills shortly after starting or raising the dosage of Mounjaro or Zepbound. This could make birth control pills less effective.
And while not a direct interaction, it’s not recommended to drink alcohol while taking Mounjaro or Zepbound. Alcohol can worsen gastrointestinal side effects, raise your risk for hypoglycemia, and affect potential health benefits.
6. Insurance coverage may be different for Mounjaro and Zepbound
Insurance coverage of Mounjaro and Zepbound varies between plans. And when it comes to Zepbound, why you’re using it may affect whether it’s covered.
Many insurance plans, including most Medicare plans, cover Mounjaro for Type 2 diabetes. If you’re using Zepbound for weight loss, your plan may not cover the medication. But if you’re using it for OSA, there’s a greater chance that Zepbound may be covered.
Brand-name medications, such as Mounjaro and Zepbound, often have higher copays than generic medications that have the same approved uses. And some plans may require you and your medical care team to take extra steps, such as a prior authorization, before they’ll cover them.
You can check your insurance plan’s formulary (a list of covered medications) to see if Mounjaro or Zepbound are covered. Many plans have their formularies available online. You may also be able to request a copy by mail. Contact the customer support department for your health insurance plan to discuss details about coverage.
Can you use Zepbound and Mounjaro together?
No, you shouldn’t use Zepbound and Mounjaro at the same time. As discussed, they both contain the same active ingredient (tirzepatide). You’d essentially be doubling up on your medication if you used both. Using more tirzepatide than recommended raises your risk of side effects, and it doesn’t necessarily make the medication work better or faster.
How to save on Mounjaro and Zepbound
There are ways to save on Mounjaro and Zepbound, which are only available as brand-name medications. Both Mounjaro and Zepbound have copay savings programs available from the manufacturer. If you have commercial insurance, you may be eligible to pay as little as $25 per prescription for either Mounjaro or Zepbound.
If your commercial insurance plan doesn’t cover Zepbound, you may be able to pay $650 for a 30-day supply. Lower-cost single-dose vials are also available through LillyDirect for $349 (2.5 mg) and $499 (5 mg, 7.5 mg, and 10 mg) per month.
Frequently asked questions
You may be able to switch from Mounjaro to Zepbound, depending on why you’re using them. Mounjaro is only approved for Type 2 diabetes. Zepbound is approved for weight loss and obstructive sleep apnea (OSA). If all of these uses apply to you, then you could switch between Mounjaro and Zepbound. It’s possible your insurance plan may have better coverage for one of them.
Yes, Zepbound and Mounjaro both contain the same active ingredient: tirzepatide. And they come in the same doses, ranging from 2.5 mg to 15 mg. So if you’re using 5 mg of Mounjaro, this is equivalent to 5 mg of Zepbound.
The bottom line
Mounjaro and Zepbound are two brand names for the medication tirzepatide. These once-weekly injections share many similarities, including their dosages, side effects, and drug interactions. The biggest difference is that Mounjaro is FDA approved for Type 2 diabetes, while Zepbound is approved for weight loss and obstructive sleep apnea. There may also be differences in insurance coverage for each.
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References
Eli Lilly and Company. (2025). Label: Mounjaro- tirzepatide injection, solution [package insert]. DailyMed.
Eli Lilly and Company. (2025). Label: Zepbound- tirzepatide injection, solution [package insert]. DailyMed.
Kamrul-Hasan, A. B. M., et al. (2025). Tirzepatide and cancer risk in individuals with and without diabetes: A systematic review and meta-analysis. Endocrinology and Metabolism.
Lilly Investors. (2025). Lilly launches additional Zepbound vial doses and offers new savings for self-pay patients.
Nagendra, L., et al. (2023). Semaglutide and cancer: A systematic review and meta-analysis. Diabetes and Metabolic Syndrome: Clinical Research and Reviews.
Wen, J., at al. (2025). Exploring the effects of tirzepatide on obstructive sleep apnea: A literature review. Cureus.
