If you are considering using medication to help you treat type 2 diabetes or lose weight, you may have heard about Mounjaro® or Zepbound®. Both medications contain the same active ingredient (tirzepatide) but they are FDA-approved for different medical conditions. Mounjaro is FDA-approved to treat type 2 diabetes while Zepbound is FDA-approved for weight loss . Read on if you are curious about the differences between Mounjaro vs Zepbound including how they work, their possible side effects, and if they might be right for you.

Mounjaro or Zepbound? What you need to know

Both Mounjaro and Zepbound contain the same active ingredient, tirzepatide. Tirzepatide is a single molecule that has the ability to mimic glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). GLP-1 and GIP are both naturally occurring hormones in the body. The dual effect of tirzepatide on both the GLP-1 and GIP receptors has many downstream effects including lowering blood sugar and reducing food intake and cravings. However, there are some important differences between the two medications.

Get to know Mounjaro

Mounjaro is the brand name for tirzepatide that is FDA-approved to treat type 2 diabetes. By targeting both the GLP-1 and GIP receptors, it stimulates the release of insulin by the pancreas which lowers blood sugar levels. It can also help to improve insulin sensitivity and promote weight loss in people with type 2 diabetes. A study found that after 40 weeks the average hemoglobin A1c (a marker for blood sugar control) dropped by 2% in patients with diabetes taking the highest dose of Mounjaro.

To put this in perspective, a hemoglobin A1c of 6.5% and higher is consistent with type 2 diabetes and a normal hemoglobin A1c is 5.6% or less. If you have type 2 diabetes and your hemoglobin A1c is 7.5%, after taking Mounjaro it’s possible it could drop by 2% bringing the hemoglobin A1c down to 5.5% which is in the normal range.

Introducing Zepbound

Zepbound is the brand name for tirzepatide that is FDA-approved for weight loss in individuals with a BMI of 30+ or a BMI of 27+ with a weight related condition (such as high blood pressure, high cholesterol, sleep apnea, etc.) in combination with reducing calorie intake and increasing physical activity. As a dual GLP-1/GIP agonist, Zepbound acts on the brain to decrease appetite and cravings by binding to GLP-1 receptors, and the GIP activity is thought to promote additional weight loss in part due to its effects on lipid and glucose metabolism. In the SURMOUNT-1 trial, Zepbound led to an average of 22.5% total body weight loss in people taking the medication at the highest dose (15 mg) for one year, and 16% total body weight loss for those on a lower maintenance dose of 5 mg.

Zepbound vs Mounjaro: Comparing medications

While Mounjaro and Zepbound contain the same active ingredient, there are a few key differences that should be considered when deciding if the medication may be right for you.

FDA-approved indication

Mounjaro was FDA-approved for the treatment of type 2 diabetes in 2022. Since then, studies have demonstrated tirzepatide as a safe and effective medication to help patients living with obesity achieve significant weight loss. This led to the FDA-approval of Zepbound for weight loss in November 2023.

Dosages

Both Mounjaro and Zepbound are available in 6 different doses, beginning with 2.5 mg and increasing by increments of 2.5 mg to a maximum dose of 15 mg. The medication is administered weekly via a single-use pen. The pens are designed to deliver one entire dose (e.g. 5 mg rather than two doses of 2.5 mg). Typically every 4 weeks the dose of the medication is increased as long as it is tolerated and safe to do so. Some patients stay at lower doses rather than increase to the full 15 mg dose depending on how they are responding to the medication.

Eligibility

Mounjaro and Zepbound are FDA-approved for different uses (indications), and therefore have different eligibility requirements. Mounjaro is approved to treat adults with type 2 diabetes, and often insurance will not cover this medication if a person does not have the diagnosis of type 2 diabetes. Zepbound is FDA-approved to treat obesity in adults with obesity (BMI 30+) or overweight (BMI 27+) who also have a weight-related medical condition. However, insurance companies may choose their own BMI cut-offs for eligibility that are different from these. For example, Zepbound coverage may require a BMI of 40 or higher with certain insurance plans.  

Please note that even if you have type 2 diabetes, obesity or overweight these medications may not be appropriate for you. Your medical history, current medications you are taking, and potential risks of taking this medication are just some of the important factors that must be taken into consideration prior to receiving a prescription.

Insurance coverage

Mounjaro and Zepbound are both expensive medications and coverage can vary depending on your insurance plan. Most plans require prior authorization for these medications, a process where your medical clinician must provide information to your insurance company to verify your eligibility for taking the medication. Even if the medication is covered, patients may still have copayments or deductibles to meet before receiving full coverage. It's important to note that while a medication may be listed as a covered benefit, there could be specific eligibility criteria for coverage. For example, Mounjaro may be a “covered benefit” but if you do not have the diagnosis of type 2 diabetes then it is extremely unlikely insurance will cover this medication in your case.

To determine which medications are covered by your plan, you can consult your plan's drug formulary, a comprehensive list of covered generic and brand-name prescription drugs. Another option is to reach out to your insurance provider directly to confirm which medications are covered under your specific plan.

Side effects

Like any medication, both Mounjaro and Zepbound have potential side effects that should be considered before getting started. Common side effects include:

• Heartburn
• Nausea
• Vomiting
• Diarrhea
• Abdominal discomfort
• Fatigue

Gallbladder disease is another potential side effect, and other rare side effects have been described. These side effects are more likely to occur as you increase your dose of the medication. It is important to speak with your healthcare provider if you begin to experience side effects on any medication so that they can create a plan to address these issues.

Zepbound weight loss results

While Mounjaro and Zepbound both contain tirzepatide, Zepbound is the only medication that is specifically FDA-approved for weight loss. The amount of weight one can lose while taking Zepbound will vary from person to person as weight loss is influenced by a numerous factors including nutrition, physical activity, environment, medical history, and other medications you may be taking.

Zepbound has demonstrated in clinical trials the most significant weight loss outcomes of any FDA-approved weight loss medication available to date. When taking the highest dose of Zepbound, patients lost on average 22.5-26% of their total body weight based on the SURMOUNT-1 and SURMOUNT-3 trials.  

What is taking Mounjaro or Zepbound like?

It is important to work with a healthcare provider when making the decision to begin either medication. Your healthcare provider will consider factors such as your medical history, current medications, side effect profile, and insurance benefits prior to recommending a medication to you. Having close follow-up with your  healthcare provider while on either medication can also help in terms of implementing lifestyle changes such as a low calorie eating pattern and increasing physical activity which are essential parts of your treatment plan. Both medications follow a specific dosing schedule and regular check-ins with your doctor help ensure that the medication is still safe and effective for you.

When taking these medications, you may notice that your appetite is lower and you get fuller faster. Some people report that they tend to get heartburn or become nauseated more easily, especially if eating fatty or spicy foods.

When taking Mounjaro for diabetes, you should start to see improvement in blood sugar levels. If taking Zepbound for weight loss, you should achieve at least 5% weight loss after 3 months on the medication. If a person has not reached that benchmark, it’s less likely that this will be an effective medication and alternative treatment options should be considered.

Mounjaro vs Zepbound: Find your right fit

Interested in starting Mounjaro or Zepbound? Be sure to discuss your options with a weight loss expert! At Form Health, patients work 1:1 with a doctor who is board certified in obesity medicine and, if appropriate, will carefully review FDA-approved medication options that are safe for you and your needs. You’ll also work with an experienced Registered Dietitian to develop a personalized weight loss plan just for you addressing nutrition, physical activity, and mindset shifts.

Find out if you are eligible by taking our quiz or send a message to get in touch with us directly at info@formhealth.co.

Zepbound® and Mounjaro® and their delivery device bases are registered trademarks owned or licensed by Eli Lilly and Company, its subsidiaries, or affiliates.

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Disclaimer: The content made available on The Form Health Medical Weight Loss Blog represents the views and opinions of the authors and not those of other entities, such as the manufacturers of products mentioned therein.