The last decade has seen the introduction of many diabetes medications with weight loss effects. A good example of these drugs is Mounjaro, which contains tirzepatide as an active ingredient.

Mounjaro's weight loss efficacy prompted the Food and Drug Administration (FDA) to approve tirzepatide for weight management under another brand name: Zepbound.

This recent approval has stirred up an essential question: Can each of these medications be used for an unapproved treatment and expect the same result since they contain the same active ingredient?

Let's compare the two drugs based on current facts.

Key Facts

  • Mounjaro and Zepbound contain the same active ingredient: Tirzepatide.

  • While both can trigger weight loss, the FDA has approved only Zepbound for weight management. Mounjaro is approved for treating type 2 diabetes.
  • Mounjaro and Zepbound share exact working mechanisms, dosing strengths, side effects, drug interactions, and contraindications.
  • Both medications are injected subcutaneously once weekly.
  • Insurance coverage for Mounjaro and Zepbound differs depending on your plan. Some insurance plans may cover Mounjaro for Type 2 diabetes. However, it's common for insurance plans to offer limited or no coverage for weight-loss medications, and Zepbound is no exception.

Comparing Zepbound and Mounjaro

Zepbound and Mounjaro offer practical strategies for shedding pounds and improving overall health. Unlike Wegovy and Ozempic, which share the same active ingredient but have different dosing strengths, Zepbound and Mounjaro have the same ingredient and dosing strength. In other words, Zepbound and Wegovy are practically the same drugs. But why are they approved for different uses? How do they compare? Let's find out.

Approved Usage

While Zepbound and Mounjaro are practically the same drug, the main difference lies in their intended use. Zepbound is prescribed for patients with obesity (BMI of 30 or higher) or overweight individuals (BMI of 27 or higher) who have weight-related health issues like hypertension, high cholesterol, or type 2 diabetes. On the other hand, Mounjaro was initially created for people with type 2 diabetes to help them lose weight and improve the effects of the disease.

Mechanism of Action

Mounjaro and Zepbound work similarly since they both have tirzepatide as a pharmaceutical ingredient.

Tirzepatide activates glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors. Its amino acid sequence has a C20 fatty diacid part that binds to albumin, making it last longer in the body.

Tirzepatide also helps insulin release from the pancreas and lowers blood sugar levels. Another way tirzepatide controls blood sugar is by helping glucose move from your bloodstream into your cells and decreasing the amount of new glucose your liver makes. It also slows the passage of food through your digestive tract, helping you to feel full longer - and sends signals to your brain to regulate your appetite.

Tirzepatide's working mechanism also involves boosting adiponectin levels. Adiponectin is an adipokine secreted by adipocytes. It is a well-known homeostatic factor for regulating glucose levels, lipid metabolism, and insulin sensitivity through its anti-inflammatory, anti-fibrotic, and antioxidant effects.

Dosing and Administration

Mounjaro and Zepbound have the same dosing strengths and are available in six doses: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg.

The recommended starting dose of Zepbound and Mounjaro is 2.5 mg, which should be taken every week. After the first four weeks, your doctor may subsequently increase the doses in 2.5 mg increments after at least four weeks until the maintenance dose is reached. The maximum dosage of both drugs is 15 mg, and they are both administered subcutaneously (under the skin, preferably in the fatty areas of the abdomen).

The recommended maintenance doses of Zepbound and Mounjaro in adults are 5 mg, 10 mg, or 15 mg, depending on treatment response and tolerability.

Side Effects

Since Zepbound and Mounjaro have the same active ingredients and dosing strengths, they share the same side effects.

The most common side effects of Zepbound and Mounjaro are typically gastrointestinal. They are usually mild and wear off in a few weeks as the body adjusts to the medicine. These common side effects include Nausea and vomiting, diarrhea or constipation, heartburn, stomach pain, Low appetite, burping, and gas.

On rare occasions, some people who take Zepbound or Mounjaro may experience severe adverse reactions to the drug. Some of these severe side effects are,

  • Low blood glucose (typically mild hypoglycemia). No incidence of severe hypoglycemia was observed with the use of tirzepatide in this study.
  • Gallbladder disease
  • Pancreatitis (inflammation of the pancreas)
  • Kidney issues
  • Temporary worsening of diabetic retinopathy
  • Severe gastrointestinal problems
  • Boxed Warning for possible thyroid tumors, including cancer.

Drug Interactions

As with the side effects, Zepbound and Mounjaro share similar drug interactions since they contain the same ingredient: Tirzepatide.

Tirzepatide helps insulin release from the pancreas and lowers high blood sugar levels. Hence, it interacts with other medications that affect insulin release, such as insulin injections, sulfonylureas like glipizide (Glucotrol XL), and glinides like repaglinide. If you must take insulin or sulfonylureas with Zepbound or Mounjaro, your doctor may lower the dosage to prevent hypoglycemia. It is, however, crucial to note that Mounjaro or Zepbound has a low risk for hypoglycemia if taken alone.

Mounjaro and Zepbound also delay food movement through the digestive system, which can slow oral medication absorption. This might affect how your body takes in these medications.

Contraindications

Zepbound and Mounjaro are contraindicated in,

  • Patients with known severe hypersensitivity to tirzepatide,
  • Patients with a personal or family history of medullary thyroid carcinoma,
  • Patients with Multiple Endocrine Neoplasia syndrome type 2.

Cost, Accessibility, and Insurance Coverage

The price for a one-month supply of Zepbound is around $1,059.87, while Mounjaro costs around $1,023.04 for a one-month supply, making Zepbound just slightly pricier.

Eligible people with commercial insurance might pay as little as $25 for a one-month or three-month prescription with the Mounjaro or Zepbound Savings Card.

If your insurance doesn't cover Zepbound, you could be eligible to pay as low as $550 per month, about half the list price.

For patients with commercial drug insurance that doesn't cover Mounjaro: To get up to $573 off your one-month prescription of Mounjaro, you need to have commercial drug insurance that doesn't cover Mounjaro and a prescription that matches the FDA-approved product labeling.

Frequently Asked Questions

Does Zepbound Cause High Blood Pressure?

No. Zepbound will not cause high blood pressure but will lower it instead. A recent analysis shows that obese people who took Zepbound saw a reduction in blood pressure similar to or better than results usually seen with traditional drugs to treat high blood pressure.

Another study published in the journal Hypertension states that patients taking Zepbound experienced a significant reduction in their systolic blood pressure.

Does Zepbound Help with Insulin Resistance?

Yes. As a dual GLP-1/GIP receptor agonist, Zepbound stimulates insulin release by the pancreas, lowers blood sugar levels, and improves insulin sensitivity.

Conclusion

Mounjaro and Zepbound are two brand names for the same drug: Tirzepatide. Each of them is administered subcutaneously once weekly. Zepbound and Mounjaro also share similar dosages, side effects, and drug interactions. The main distinction is that Mounjaro is FDA-approved for treating Type 2 diabetes, whereas Zepbound is approved for weight loss.

Sources

At Diabetic Me, we are committed to delivering information that is precise, accurate, and pertinent. Our articles are supported by verified data from research papers, prestigious organizations, academic institutions, and medical associations to guarantee the integrity and relevance of the information we provide. You can learn more about our process and team on the about us page.

  1. National Library of Medicine Tirzepatide
  2. lilly.com Medication Guide ZEPBOUND® (ZEHP-bownd) (tirzepatide) injection, for subcutaneous use
  3. National Library of Medicine Adiponectin: Role in Physiology and Pathophysiology
  4. National Library of Medicine Adverse Events Related to Tirzepatide
  5. National Library of Medicine Tirzepatide for type 2 diabetes
  6. AHA Journals Tirzepatide Reduces 24-Hour Ambulatory Blood Pressure in Adults With Body Mass Index ≥27 kg/m2: SURMOUNT-1 Ambulatory Blood Pressure Monitoring Substudy
  7. National Library of Medicine Tirzepatide, a New Era of Dual-Targeted Treatment for Diabetes and Obesity: A Mini-Review
  8. lilly.com Savings & Support for Mounjaro
  9. lilly.com Savings & Support for Zepbound

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About the Author

Ely Fornoville

Hi, I'm Ely Fornoville, and I am the founder of Diabetic Me. Being a type 1 diabetic since 1996, I developed a passion to help people learn more about diabetes. I write about diabetes and share stories from other diabetics around the world. I currently use a Medtronic Guardian 4 CGM and a MiniMed 780G insulin pump with Humalog insulin.

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