What you’ll learn:
- Zepbound® and Mounjaro® are the same medication under two different brand names with different FDA-approved uses.
- Tirzepatide is the active ingredient in both Zepbound® and Mounjaro®.
- Clinical trials show people can lose up to an average of 20% of their body weight when using these medications over time.
The rise of GLP-1 receptor agonists has reshaped the approach to weight loss, with many first learning about them through Ozempic®. These mimic hormones that influence appetite and improve blood sugar regulation, helping people lose weight more effectively. Among them, tirzepatide stands out because of its dual-action mechanism, which may offer even greater weight loss potential.
Tirzepatide is the key ingredient in two different medications: Mounjaro® and Zepbound®. While they share the same active component, they have different approved uses. Mounjaro® was initially approved for managing type 2 diabetes, while Zepbound® is FDA-approved specifically for weight loss. Along with these differences, factors like pricing, insurance coverage, and how they’re taken can all influence which one might be a better fit for you.
If you’re weighing your options, understanding how Zepbound® and Mounjaro® compare can help you make an informed choice. Let’s take a closer look at what sets these two apart and what that means for your weight loss journey.
Zepbound® vs. Mounjaro®: How do they work?
Because Zepbound® and Mounjaro® are the exact same medication (tirzepatide) under different names, they work exactly the same.
Tirzepatide mimics two hormones involved in appetite and blood sugar regulation—GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). These hormones are normally released by the intestines after you eat. They play a big role in managing blood sugar and appetite. Here’s what they do:
- GLP-1 helps regulate blood sugar by stimulating insulin release, reducing glucagon (a hormone that raises blood sugar), slowing down digestion, and signaling fullness to the brain.
- GIP may further support appetite regulation and fat metabolism.
Tirzepatide binds to the same receptors that GLP-1 and GIP do, activating those pathways to help lower blood sugar and reduce hunger. The result? You feel fuller sooner, eat less, and your blood sugar stays more stable, making it an effective tool for people managing type 2 diabetes and those looking to lose weight.
What are the similarities?
Zepbound® and Mounjaro® both contain tirzepatide and work the same way to regulate appetite, slow digestion, and regulate blood sugar. Let’s take a look at some other similarities:
They share a manufacturer
Both Zepbound® and Mounjaro® are made by Eli Lilly, a pharmaceutical company that specializes in treatments for diabetes and weight management. Along with these medications, Eli Lilly also produces Trulicity® (dulaglutide), which is FDA-approved to treat type 2 diabetes and occasionally prescribed off-label for weight loss.
You take them the same way
Both are once-weekly injections that you give yourself in the upper arm, stomach, or thigh. Mounjaro® and Zepbound® are both administered with a prefilled injection pen. Zepbound® also comes in a vial and syringe form if you get it through the manufacturer’s Lilly Direct program.
Step-up dosing schedule
They also follow a gradual dosing schedule, starting at a lower dose and increasing over time to help minimize side effects like nausea or digestive discomfort. This approach allows the body to adjust, improving tolerance and long-term effectiveness.
Same side effects
Since Zepbound® and Mounjaro® are the same medication, they come with the same potential side effects. Many experience mild to moderate digestive symptoms as their body adapts. We’ll go into more detail on side effects later in the article.
What are the differences?
Zepbound® and Mounjaro® don’t have many differences beyond their names, but there are a couple. Their approved uses and potential insurance coverage set them apart.
Approved uses
Both medications have specific approvals, but off-label use is common.
- Zepbound® is FDA-approved for weight loss for people with a BMI of 30 or higher or 27 and higher with at least one weight-related condition, such as high blood pressure. It’s also approved for treating obstructive sleep apnea (OSA).
- Mounjaro® is FDA-approved to treat type 2 diabetes, though it can also be prescribed off-label for weight loss under the same BMI guidelines as Zepbound®.
Insurance coverage
Most insurers won’t cover medications when used for weight loss. Mounjaro® is more likely to be covered for people who use it for type 2 diabetes.
Why do Zebound® and Mounjaro® have different names?
Both medications are tirzepatide in the exact same doses, so why are they called different things? It’s all about FDA labeling and how the drug is marketed. Even though it’s the same drug, drug companies must go through separate approval processes for each intended use. That means different clinical trials, dosing guidelines, insurance coverage, and even branding.
- Mounjaro® was approved first (in 2022) for managing blood sugar in people with type 2 diabetes.
- Zepbound™ was approved later (in 2023) for chronic weight management, using results from separate clinical trials focused on weight loss.
Think of it like this: Same actor, different roles.
Can you switch between Zepbound® and Mounjaro®?
Yes, switching between Zepbound® and Mounjaro® is possible, but it should always be done with guidance from a healthcare provider. Since both medications contain the same doses of tirzepatide, transitioning from one to the other is generally straightforward. Here are some possible reasons why you may want to switch medications:
- Insurance coverage – If your insurance drops or begins to cover one, you might want to switch to reduce costs.
- Availability issues – While tirzepatide has been removed from the FDA’s shortage list, it could still be difficult to find due to the popularity of these medications.
- Cost – If you are using the prefilled pen of Mounjaro® or Zepbound® and want to switch to the lower-cost vial and syringe option, discuss this with your doctor.
Lose 48% more weight
with Noom than just meds alone
Zepbound® vs Mounjaro®: Which is better for weight loss?
Both Zepbound® and Mounjaro® contain tirzepatide in the exact same amounts. Studies show that in clinical trials, people taking tirzepatide lost up to 21% of their body weight after 72 months. When it comes to which one is best for you, that depends on what you can pay, your insurance coverage, and how you want to take it: prefilled pen or vial and syringe.
How much weight can you lose on Zepbound® and Mounjaro®?
For both, you are started at the lowest dose (2.5 mg), and it will be increased as tolerated to keep you losing steady weight. The maximum dose is 15 mg for both, but most people see significant weight loss with all doses. In one study, people were able to lose the following average percentage of body weight over 16 months at the following doses:
- 5 mg weekly: 16% weight loss
- 10 mg weekly: 21% weight loss
- 15 mg weekly: 23% weight loss
People who were taking the placebo lost only about 2% of their body weight. These results mean the highest-dose group (15 mg) averaged about 20% more body weight loss than the placebo, an unprecedented magnitude for a weight loss medication.
But, as you can see, many didn’t even need the highest dose to lose a lot of weight. Even at the lowest dose, half of the participants lost 15% of their body weight. Taking tirzepatide approaches the amount people can lose with bariatric surgery in some cases.
How long does it take to see results?
Weight loss with Zepbound® and Mounjaro® happens gradually, with noticeable changes occurring over several months. While individual results vary, most people see a progression of effects as their dosage increases and their body adjusts to the medication.
Both Zepbound® and Mounjaro® follow a dose-escalation schedule, meaning you start at a lower dose and gradually increase to minimize side effects. Higher doses tend to lead to more significant weight loss, but results are maximized when combined with nutritious eating and regular physical activity.
- First few weeks – During the first 2 to 4 weeks, many people notice a reduction in appetite and may lose a few pounds. This early phase is when your body is adapting to the medication, and while the weight loss may be small, it sets the foundation for more significant progress.
- 1 to 3 months – With consistent use and dose increases, weight loss typically becomes more noticeable within the first 1 to 3 months. This phase is key for developing healthy eating habits and lifestyle adjustments, as the medication helps control cravings and portion sizes.
- 6+ months – By 6 to 12 months, most people experience substantial weight loss, often reaching 15 to 20% of their body weight at higher doses.
Who can take Zepbound® and Mounjaro® for weight loss?
Both Zepbound® and Mounjaro® can be prescribed for weight loss, but eligibility depends on medical history and individual health conditions. You may be prescribed either of these for weight loss if you have:
- A BMI of 30 or higher
or
- A BMI of 27 or higher and at least one weight-related condition (like high blood pressure or high cholesterol).
Who can’t take Zepbound® or Mounjaro®?
While Zepbound® and Mounjaro® can be helpful for many people, they’re not the right fit for everyone. Here’s a quick guide on who should steer clear of these medications:
- Anyone with a personal or family history of Medullary Thyroid Carcinoma (MTC)
- People with Multiple Endocrine Neoplasia Syndrome Type 2 (MEN 2)
- People who are pregnant, planning to become pregnant, or breastfeeding
Talk to your doctor about where they are right for you if you have:
- A history of severe gastrointestinal conditions
- A history of pancreatitis
If you take Zepbound® or Mounjaro® to lose weight, will you need to keep taking them forever?
Whether you need to continue taking Mounjaro® or Zepbound® indefinitely depends on your weight-loss goals, how your body responds to the medication, and your ability to maintain results with lifestyle changes. Some people transition to a lower maintenance dose, while others may stop entirely. However, studies suggest that discontinuing these medications without strong lifestyle habits can lead to weight regain.
This happens because the medication helps regulate appetite, metabolism, and insulin levels, and once it’s discontinued, those effects gradually fade. Here’s what happens if you stop taking medication:
- Increased appetite and cravings due to the body’s natural hunger signals returning.
- A slowdown in metabolism, making it easier to regain weight.
- Potential fluctuations in blood sugar levels, especially for those with insulin resistance or diabetes.
For some, switching to a lower maintenance dose can help sustain weight loss while minimizing long-term medication use. Regardless of whether you continue the medication, the key to long-term success is adopting healthy habits alongside treatment. Regular physical activity, balanced nutrition, mindful eating, and behavior changes all play a role in sustaining weight loss.
Zepbound® vs. Mounjaro®: Costs
Zepbound® and Mounjaro® have similar costs, but what you will end up paying depends on various factors.
Zepbound
The list price of Zepbound® is about $1,086 per month without insurance for the prefilled pens. If you don’t have insurance, you can get your prescription filled through Eli Lilly’s LillyDirect platform. Through the program, single-use vials are paired with a syringe for:
- $349 for the 2.5 mg dose
- $499 for the 5, 7.5 mg, and 10 mg doses
Learn more about the cost of Zepbound®.
Mounjaro
Mounjaro® costs about $1,080 per month without insurance. Insurance coverage for weight loss is rare, but if you have partial coverage, manufacturer savings cards are available that can reduce the price.
Learn more about the cost of Mounjaro®.
Zepbound® vs Mounjaro®: Side effects and warnings
Zepbound® and Mounjaro® can cause side effects ranging from mild and temporary to more serious, requiring immediate medical attention. Since both drugs contain tirzepatide, they share the same side effect profile.
Common side effects
Many people experience mild side effects when starting Zepbound® or Mounjaro®. These are usually temporary and decrease as your body adjusts to the medication. Common side effects include:
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Stomach pain
Learn how to manage the side effects of Zepbound® and Mounjaro®.
Serious side effects
While rare, serious side effects can occur with both Zepbound® and Mounjaro®. If you notice any of the following symptoms, seek medical attention immediately:
- Pancreatitis: Be alert for persistent stomach pain, especially if it radiates to your back.
- Allergic reactions: Symptoms include swelling of the face, lips, tongue, or throat; difficulty breathing or swallowing; severe rash or itching; dizziness; or a rapid heartbeat.
- Vision changes: Get any sudden vision changes checked immediately.
- Low blood sugar (hypoglycemia): If you have diabetes and use medications like insulin or other blood sugar-lowering drugs, watch for symptoms like dizziness, shakiness, sweating, or confusion.
- Kidney problems: Symptoms like swelling, fatigue, shortness of breath, or changes in urination could signal kidney issues, especially if dehydration occurs from nausea, vomiting, or diarrhea.
- Thyroid tumors: Watch for lumps or swelling in your neck, hoarseness, difficulty swallowing, or shortness of breath. Animal studies have shown a potential link between tirzepatide and thyroid tumors, but these types of tumors haven’t been reported in people.
- Depression or suicidal thoughts: If you notice new or worsening mental health symptoms, seek help immediately.
For a full breakdown of potential risks, see the Zepbound® safety information and Mounjaro® safety information.
Zepbound® vs. Mounjaro®: Dosage and administration
Both Zepbound® and Mounjaro® follow a step-up dosing schedule to help the body adjust while minimizing side effects. As we’ve said, Mounjaro® comes only as a prefilled pen, while Zepbound® offers both a prefilled pen and a vial-and-syringe option.
For both, treatment begins with a 2.5 mg injection once a week. After this initial period, the dose increases to 5 mg weekly. If additional weight loss or blood sugar control is needed, the dose can be adjusted in 2.5 mg increments as needed and tolerated up to a maximum of 15 mg weekly.
This slow, step-up approach helps reduce side effects like nausea and digestive discomfort, allowing the body to adapt to the medication.
How they are taken
Both Zepbound® and Mounjaro® are injected under the skin in areas with sufficient fatty tissue for absorption, like the abdomen, thigh, and upper arm. Rotating injection sites with each dose is important to prevent irritation or bruising.
Before giving yourself an injection, always check that the medication is clear and colorless to slightly yellow. If the solution appears cloudy or contains particles, it should not be used. Clean the injection site with an alcohol swab and insert the needle at a 90-degree angle. After the injection, properly dispose of the needle, pen, or syringe in a designated sharps container.
For those using Zepbound® vials, carefully draw the medication into the syringe and inject as above, gently pinching the skin while inserting the needle.
As with any medication, it’s important to follow your healthcare provider’s guidance to ensure safe and effective use.
Zepbound® vs Mounjaro®: Which is right for me?
Choosing between Mounjaro® and Zepbound® comes down to your health goals, insurance coverage, and personal preferences.
| Factor | Mounjaro® | Zepbound® |
|---|---|---|
| FDA approval and uses | FDA-approved for type 2 diabetes Off-label for weight loss | FDA-approved for weight loss and obstructive sleep apnea (OSA) |
| Weight loss results | 15-20% of body weight at the highest dose | Same |
| Doses | 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg | Pens: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg Vial & syringe: 2.5 mg, 5 mg, 7.5 mg, and 10 mg |
| List price/month | $1,090 | Pens: $1,086 Vial & syringe: $349 (2.5 mg), $499 (5 mg, 7.5 mg, 10 mg) |
| Insurance coverage | Possible for type 2 diabetes, unlikely to be covered for weight loss See full cost details for Mounjaro® | Unlikely to be covered for weight loss See full cost details for Zepbound® |
Alternatives to Zepbound® and Mounjaro®
While Zepbound® and Mounjaro® are highly effective for weight loss, they’re not the only options available. If you’re looking for an alternative due to cost, insurance limitations, or personal preference, there are other medications that work in different ways to support weight loss. Here’s a breakdown of your options:
| Medication | Brand names and uses | Cost per month (without insurance) | Effectiveness | How it’s taken |
|---|---|---|---|---|
| Semaglutide – GLP-1 receptor agonist | Ozempic®: type 2 diabetes, off-label weight loss Wegovy®: weight loss and heart disease Rybelsus®: type 2 diabetes, off-label weight loss | Ozempic®: $998 Learn more Wegovy®: $1,350 $499 (NovoCare Pharmacy) Learn more Rybelsus®: $998 Learn more | Ozempic®/Wegovy®: People lost an average of 15% of body weight in 68 weeks with injectable semaglutide Rybelsus®: People lost about 4% of their body weight | Ozempic®/Wegovy®: Weekly injection Rybelsus®: Daily pill |
| Liraglutide – GLP-1 receptor agonist | Victoza®: type 2 diabetes, off-label weight loss Saxenda®: weight loss and heart disease Generic liraglutide: type 2 diabetes, off-label weight loss | Victoza®: $800 to $1,400 Saxenda®: $1,350 Learn more. Generic liraglutide: $470 – $700 | People lost an average of 5-6% of body weight in one year. | Daily injection |
Other medications
GLP-1s aren’t the only options. These medications work in different ways and can be prescribed to help people lose weight if needed.
| Medication | Brand names | Cost per month (without insurance) | Effectiveness | How it’s taken |
|---|---|---|---|---|
| Metformin (off-label weight loss) | Glucophage®, Fortamet®, Glumetza® | Generic: $4–$15 Brand name: $100–$500+ Learn more. | People lost an average of about 6% of their body weight over six months while taking metformin. | Pill taken up to two times daily |
| Phentermine | Lomaira®, Adipex-P® | $27-$100 | About 80% of people with a BMI of 30 or more lost at least 5% of their body weight in 6 months. | Daily pill |
| Diethylpropion | Tenuate®, Tenuate Dospan® | $40-$85 | People lost an average of 10% of their body weight in 6 months. | Pill taken one to three times daily |
| Naltrexone and bupropion | Contrave® | $600-$800 CurAccess™: $99 | People lost an average of 7 to 8% of their body weight in a year. | Pill taken up to twice daily |
| Orlistat | Xenical®, Alli® | $50-$800 | People in a study lost about 10% of body weight after taking Orlistat for 1 year. | Pill taken three times daily with meals. |
Lose 48% more weight
with Noom than just meds alone
Making the right choice between Zepbound® vs Mounjaro®
When it comes to choosing between Zepbound® and Mounjaro®, the key thing to remember is that you’re working with the exact same medication—tirzepatide—just under different brand names with different FDA-approved uses. The biggest differences come down to insurance coverage, cost, and how you plan to use it. If you’re living with type 2 diabetes, Mounjaro® may be more likely to be covered. If your primary goal is weight loss or treating OSA, Zepbound® is the one that’s FDA-approved for those conditions. But in terms of how they work in the body, how much weight you can lose, and how they’re taken, they’re essentially identical.
No matter which option you’re considering, it’s important to work closely with your healthcare provider to figure out what’s right for you, whether that’s starting a GLP-1 like tirzepatide, switching medications, or building a plan that supports long-term results. These medications are powerful tools, but they work best when paired with sustainable lifestyle changes like regular movement, nutritious meals, and support systems that keep you motivated. With the right combination of tools, you can make meaningful progress toward your health goals.
Note: Ozempic®, Mounjaro®, Rybelsus®, Victoza®, Trulicity®, and metformin are not FDA-approved to treat obesity or for weight loss.
