Late in 2023, Eli Lilly launched a new drug named Zepbound, and we’ve written about it being a marketing & strategic play. In essence, it’s a similar drug to one they already sell – Mounjaro – but with a focus on weight loss rather than diabetes.
Now that it’s been on the market a few months, you might be wondering how to choose between them. If you’re searching for a detailed comparison, you’ve come to the right place!
In this article, we’ll break down the key similarities and differences between Zepbound and Mounjaro. We’ll look at how they work, potential side effects, cost, and effectiveness for weight loss and diabetes. We’ll also provide some guidance to help you determine which one may be the better choice for you personally.
Overview of Zepbound and Mounjaro
Zepbound and Mounjaro are both tirzepatide drugs by Eli Lilly. They work in a similar way by activating the GLP-1 and GIP receptors. Specifically, they:
- Stimulate insulin release when blood sugar levels are high
- Reduce glucagon release from the pancreas
- Slow down gastric emptying
- Reduce appetite
These effects help promote weight loss in two ways. First, by lowering blood sugar after meals and reducing appetite, they can help you naturally eat less and feel full sooner. Second, by stimulating insulin release, they improve the body’s ability to utilize blood sugar for energy instead of storing it as fat.
While Zepbound and Mounjaro have many similarities, there are a few differences as well. Let’s start with their similarities – i.e. their mechanisms of action, and how they both work.
Mechanisms of Action: How Zepbound & Mounjaro Work for Weight Loss
Zepbound for Weight Loss
Zepbound is a tirzepatide and works by activating GLP-1 and GIP receptors, similarly to Mounjaro. This binding results in several effects that promote weight loss, including:
- Stimulating insulin release after meals when blood sugar levels rise, which helps utilize glucose for energy instead of storing it as fat
- Reducing levels of the hormone glucagon, which is normally released to raise blood sugar. Lower glucagon levels lead to lower glucose levels after eating.
- Slowing down how quickly food empties from the stomach, making you feel fuller for longer and eat less overall.
- Suppressing appetite by acting on receptors in the brain that control hunger and satiety.
All of these mechanisms work together to decrease calorie intake and increase calorie burning, resulting in weight loss over time for patients taking Zepbound. The medication mimics natural GLP-1 hormone that is released after eating to regulate blood sugar and appetite.
Mounjaro for Weight Loss
Like Zepbound, Mounjaro also works by mimicking a hormone in your gut called glucagon-like peptide-1 or GLP-1. This hormone slows digestion and makes you feel full sooner while eating. Mounjaro activates GLP-1 receptors in your body, which can suppress appetite and reduce hunger.
Since both medications have the same underlying drug, both Zepbound and Mounjaro can be effective for weight loss. But because they were created for different reasons – Mounjaro for diabetes and Zepbound for weight loss – their efficacies can differ.
Efficacy: Weight Loss Results From Clinical Trials
The efficacy of Zepbound and Mounjaro in clinical trials for weight loss shows significant results, indicating that both these treatments offer substantial benefits for individuals dealing with obesity or overweight, particularly those with type 2 diabetes.
For Zepbound, in the SURMOUNT-4 trial, participants achieved an additional 6.7% weight loss following a 36-week open-label lead-in period, totaling a mean weight loss of 26.0% from study entry over 88 weeks.
This indicates Zepbound’s strong performance in chronic weight management.
Mounjaro showed impressive results in the SURMOUNT-2 trial, with participants achieving average weight reductions of 13.4% on a 10 mg dose and 15.7% on a 15 mg dose compared with placebo over 72 weeks.
More than 80% of participants on either dose lost 5% or more of their body weight, underscoring Mounjaro’s effectiveness in weight loss among individuals with obesity or overweight and type 2 diabetes.
Both drugs, containing tirzepatide, have demonstrated their ability to facilitate significant weight loss, with Zepbound showing slightly higher weight loss percentages in its clinical trial.
Zepbound vs Mounjaro for Weight Loss: Clinical Trial Data
Based on clinical trials, Zepbound is more effective for weight loss.
Zepbound showed a total mean weight loss of 26.0% from study entry over 88 weeks in its clinical trials. Mounjaro demonstrated up to 15.7% weight loss in adults with obesity or overweight and type 2 diabetes.
However, it’s important to note that the contexts and specific conditions of the clinical trials may vary, affecting direct comparisons.
Mounjaro, approved for use in type 2 diabetes with observed weight loss benefits, and Zepbound, specifically approved for chronic weight management, offer promising options for individuals struggling with weight management and related health issues.
Side Effects Profile Comparison
Both drugs were well tolerated in the trials. We’ll talk about a few of the common side effects, like nausea, diarrhea, and vomiting, below.
Common side effects
Both Zepbound and Mounjaro can cause some gastrointestinal issues, though Mounjaro seems to have a higher incidence of these. The most common side effects for Zepbound are nausea, diarrhea, and constipation. For Mounjaro, nausea and diarrhea again top the list, but also include vomiting and abdominal pain. These side effects are usually mild to moderate and often subside over time or can be managed by adjusting the dosage or administration.
Serious side effects
Rare but serious side effects for both drugs include hypoglycemia or low blood sugar, pancreatitis or inflammation of the pancreas, and hypersensitivity reactions. However, Mounjaro does come with an additional risk of thyroid C-cell tumors. Both drugs also carry a risk of diabetic retinopathy complications, so you’ll need to get regular eye exams while on either medication.
Injection site reactions
Since both Zepbound and Mounjaro are injectable medications, injection site reactions like redness, itching, and rash can occur. Mounjaro seems to have a slightly higher rate of these reactions, which may be due to its higher dosage volume (2.5mg to 25mg for Mounjaro vs. 0.5mg to 1 mg for Zepbound). Using proper injection technique and rotating injection sites can help minimize these reactions.
Drug interactions
Some significant drug interactions can occur with either Zepbound or Mounjaro, especially with medications that can affect blood sugar levels. Make sure your doctor has a full list of all the medications and supplements you’re taking to determine if any interactions may occur before starting treatment. Certain medications may need to be adjusted or replaced.
In summary, while both Zepbound and Mounjaro share some common side effects, Mounjaro does seem to have a slightly higher incidence of gastrointestinal issues and injection site reactions, as well as additional risks like thyroid tumors.
However, for many people the side effects are manageable with close monitoring and dosage adjustments. The most serious risks can often be avoided by properly managing your blood sugar levels and getting recommended health checks.
Cost and Availability of Zepbound vs. Mounjaro
When deciding between weight loss medications, cost and availability are important factors to consider.
Zepbound, the newer drug, is currently more expensive but may have more coverage options. Mounjaro, though often cheaper, can still be pricey if insurance won’t cover it.
Zepbound
Zepbound costs around $1,060 per month. Because it’s still under patent, generic versions aren’t available yet. However, the manufacturer does offer a savings card that can lower your out-of-pocket costs. Many insurance plans, including Medicare and Medicaid, cover at least part of the cost. The exact amount will depend on your specific plan and benefits.
Notably, Eli Lilly planned to price Zepbound 20% lower than semaglutide, a competing weight loss drug.
Mounjaro
Because both Zepbound and Mounjaro are still branded and under patent (and by the same company, Eli Lilly!), their prices are similar. The list price for Mounjaro is close to Zepbound’s: $1,023.04 for a month’s supply.
Some insurance plans don’t cover weight loss drugs at all. Out-of-pocket costs for Mounjaro can be steep, ranging from $1,020 to $1,200 per month depending on the dosage and whether you use a savings card.
Which Patients Are Best Suited for Each Drug?
Choosing between Zepbound and Mounjaro for patients depends on their specific medical conditions, weight management goals, and overall health profile.
Here’s a general guideline on which patients might be best suited for Zepbound and Mounjaro based on their approved uses and clinical trial outcomes:
Zepbound
- Indicated for Weight Management: Zepbound is specifically approved for chronic weight management in adults with obesity (BMI ≥ 30 kg/m^2) or overweight (BMI ≥ 27 kg/m^2) with at least one weight-related comorbidity (e.g., hypertension, type 2 diabetes mellitus, dyslipidemia).
- Non-Diabetic Patients Focused on Weight Loss: Ideal for patients primarily focused on significant weight loss, particularly those without type 2 diabetes but with other weight-related health issues.
- Comprehensive Weight Management: Suited for individuals looking for an adjunct to a reduced-calorie diet and increased physical activity to manage their weight more effectively.
Mounjaro
- Indicated for Type 2 Diabetes Management with Weight Loss Benefit: Mounjaro is approved as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Its significant weight loss benefits, however, make it suitable for patients with type 2 diabetes who are also overweight or obese.
- Patients with Type 2 Diabetes Seeking Weight Management: Best suited for patients with type 2 diabetes who also need to manage their weight. The drug can help improve blood sugar levels while also facilitating weight loss.
- Comparison with Other GLP-1 Receptor Agonists: Might be considered for patients who have tried other GLP-1 receptor agonists (like semaglutide) but are seeking alternative options with possibly better efficacy in weight reduction or glycemic control.
Considerations for Both Drugs
- Side Effects and Contraindications: Both drugs have warnings about potential thyroid tumors, including medullary thyroid carcinoma (MTC), and should not be used in patients with a personal or family history of MTC or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
- Cost and Insurance Coverage: The accessibility of both drugs might be influenced by their cost and the extent of insurance coverage, which can be a deciding factor for some patients.
In choosing between Zepbound and Mounjaro, patients should consider their overall health, presence of type 2 diabetes, specific weight loss goals, and potential side effects or contraindications.
The Takeaway: 6 Key Differences Between Zepbound and Mounjaro
The key differences between Zepbound and Mounjaro, both of which contain the active ingredient tirzepatide and are developed by Eli Lilly, can be summarized based on their intended use, clinical trial outcomes, and patient suitability:
1. Approved Indications:
- Zepbound: Approved specifically for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity, making it a focused choice for those primarily seeking weight loss.
- Mounjaro: Approved as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus, with significant weight loss as an additional benefit, ideal for diabetic patients also looking to lose weight.
2. Clinical Efficacy in Weight Loss:
- Zepbound showed a total mean weight loss of 26.0% from study entry over 88 weeks in its clinical trials, highlighting its potent efficacy in weight management.
- Mounjaro demonstrated up to 15.7% weight loss in adults with obesity or overweight and type 2 diabetes, offering substantial weight loss alongside glycemic control benefits.
3. Patient Suitability:
- Zepbound: Suited for patients without diabetes but with obesity or overweight conditions seeking significant weight loss as part of a comprehensive weight management program.
- Mounjaro: Best suited for patients with type 2 diabetes who are also managing obesity or overweight, providing a dual benefit of improved blood sugar control and weight loss.
4. Side Effects and Contraindications: Both medications carry warnings about potential thyroid tumors, including medullary thyroid carcinoma, and are not recommended for patients with a personal or family history of MTC or MEN 2.
5. Considerations for Use: The choice between Zepbound and Mounjaro should consider the patient’s specific health conditions, weight management goals, potential side effects, cost, and insurance coverage.
6. Cost and Accessibility: Accessibility may be influenced by the cost of each medication and the coverage provided by insurance plans, with programs in place to assist with affordability for eligible patients.
While both Zepbound and Mounjaro offer significant benefits for weight loss and management, the choice between them should be tailored to the individual’s health profile, including the presence of type 2 diabetes and specific weight management needs.
FAQ: Zepbound vs. Mounjaro for Weight Management and Type 2 Diabetes
1. What is Zepbound and who is it for?
Zepbound is an FDA-approved medication for chronic weight management in adults with obesity (BMI ≥ 30 kg/m^2) or overweight (BMI ≥ 27 kg/m^2) with at least one weight-related comorbidity. It’s particularly suited for patients primarily focused on significant weight loss.
2. What is Mounjaro and who should use it?
Mounjaro is approved as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Its significant weight loss benefits also make it suitable for diabetic patients who are overweight or obese and seeking to manage their weight.
3. How effective is Zepbound in weight loss?
In clinical trials, Zepbound showed a total mean weight loss of 26.0% from study entry over 88 weeks, indicating its potent efficacy in weight management for those without diabetes.
4. How effective is Mounjaro in weight loss for people with type 2 diabetes?
Mounjaro demonstrated up to 15.7% weight loss in adults with obesity or overweight and type 2 diabetes, offering substantial weight loss alongside glycemic control benefits.
5. What are the side effects and contraindications of Zepbound and Mounjaro?
Both medications have warnings about potential thyroid tumors, including medullary thyroid carcinoma (MTC), and should not be used by patients with a personal or family history of MTC or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
6. How do I choose between Zepbound and Mounjaro?
The choice should be based on the individual’s specific health conditions, weight management goals, potential side effects, and considerations such as cost and insurance coverage. Zepbound is more focused on weight management, while Mounjaro offers dual benefits for patients with type 2 diabetes.
7. Are there any programs to help with the cost of Zepbound and Mounjaro?
Yes, both medications may have savings programs for eligible patients to help make the treatment more accessible and affordable.
