Zepbound vs. Mounjaro: Comparison Guide for Weight Loss and Diabetes Treatment

Q: Zepbound vs. Mounjaro: Comparison Guide for Weight Loss and Diabetes Treatment

Zepbound and Mounjaro contain the same active ingredient (tirzepatide) and both are made by Eli Lilly and Company, but they have different FDA approved uses and insurance coverage. Zepbound is approved for chronic weight management and obstructive sleep apnea (OSA) and Mounjaro is approved for type 2 diabetes.

Medically reviewed by Carmen Pope, BPharm. Last updated on July 18, 2025.

Official Answer by Drugs.com

Zepbound and Mounjaro contain the same active ingredient (tirzepatide) and both are made by Eli Lilly and Company, but they have different FDA approved uses and insurance coverage. Zepbound is approved for chronic weight management and obstructive sleep apnea (OSA) and Mounjaro is approved for type 2 diabetes.

Quick Comparison Table

Comparison of Zepbound vs. Mounjaro
Feature	Zepbound	Mounjaro
Active Ingredient	Tirzepatide	Tirzepatide
FDA Approval	Chronic weight management, OSA	Type 2 diabetes
Typical Insurance Coverage	Weight management benefits Sleep apnea benefits	Diabetes benefits
Patient Population	Adults with obesity or those who are overweight with comorbidities Moderate to severe obstructive sleep apnea (OSA) in adults with obesity	Adults with type 2 diabetes
Average Weight Loss	20.9% (at 15 mg, 72 weeks)	20.9% (at 15 mg, 72 weeks)
Dosing	1 time a week (subcutaneously)	1 time a week (subcutaneously)

Understanding Tirzepatide: How it Works

Tirzepatide works by activating two gut hormone receptors, GIP and GLP-1, to manage blood sugar. This:

Stimulates insulin release when blood glucose levels are elevated
Slows gastric emptying, leading to increased satiety (feeling full for longer) and better control of post-meal sugar spikes
Reduces glucagon production from the liver
Improves insulin sensitivity
Reduces appetite through central nervous system effects.

FDA-Approved Uses

Mounjaro

Primary indication: Treatment of type 2 diabetes in adults

Used alongside diet and exercise.
Helps improve blood sugar control.

Zepbound

Primary indication 1: Chronic weight management in adults with:

Obesity (BMI ≥30 kg/m²)
Overweight (BMI ≥27 kg/m²) with at least one weight-related condition (such as high blood pressure, dyslipidemia, sleep apnea)

Used in combination with reduced-calorie diet and increased physical activity.

Primary indication 2: Moderate to severe obstructive sleep apnea (OSA) in adults with obesity.

Side Effects and Safety Profile

Common side effects for both Zepbound and Mounjaro include:

Nausea (12-22% of patients)
Diarrhea (12-16% of patients)
Vomiting (6-13% of patients)
Constipation (6-9% of patients)
Stomach pain (8-11% of patients)
Decreased appetite (5-11% of patients)

Management Strategies:

Start with small, frequent meals
Avoid high-fat, greasy foods
Stay well-hydrated
Take with food if nausea occurs
Consider anti-nausea medications if severe.

Serious Side Effects and Contraindications

Contraindications:

Personal or family history of medullary thyroid carcinoma
Multiple Endocrine Neoplasia syndrome type 2
Type 1 diabetes (for Mounjaro)
Hypersensitivity to tirzepatide.

Warnings:

Risk of thyroid C-cell tumors (black box warning)
Acute pancreatitis
Acute gallbladder disease
Diabetic retinopathy complications
Acute kidney injury.

When to Call Your Doctor

Immediate medical attention needed:

Severe abdominal pain that doesn't go away
Persistent vomiting preventing fluid intake
Signs of pancreatitis (severe stomach pain radiating to back)
Symptoms of thyroid tumors (lump in neck, hoarseness, difficulty swallowing)
Severe allergic reactions.

Important Safety Information:

Not recommended for type 1 diabetes
Caution in patients with history of pancreatitis
Regular monitoring recommended during treatment.

Detailed Clinical Trial Results

Weight Loss Effectiveness with Tirzepatide (SURMOUNT Trials):

Average weight loss at 15mg dose: 20.9% of body weight over 72 weeks
Placebo comparison: 3.1% weight loss in same period
Significant weight loss (≥5%): Achieved by 91% of patients
Substantial weight loss (≥20%): Achieved by 55% of patients.

The SURMOUNT program consisted of multiple Phase 3 trials studying tirzepatide for obesity treatment:

SURMOUNT-1 (NCT04184622) studied tirzepatide in participants with obesity without diabetes
SURMOUNT-2 (NCT04657003) studied tirzepatide in people with obesity and type 2 diabetes
SURMOUNT-3 (NCT04657016) examined tirzepatide after intensive lifestyle intervention
SURMOUNT-4 (NCT04660643) looked at continued treatment for weight maintenance
SURMOUNT-5 (NCT05822830) compared tirzepatide to semaglutide for obesity treatment.

Blood Sugar Control with Tirzepatide (SURPASS Trials):

HbA1c reduction: 1.5-2.4% depending on dose
Patients achieving HbA1c <7%: 80-95% across different doses
Fasting glucose reduction: 54-80 mg/dL improvement
Superior to insulin, metformin, and other GLP-1 agonists.

The SURPASS program consisted of multiple Phase 3 trials studying tirzepatide for type 2 diabetes treatment:

SURPASS-1 (NCT03954834) studied tirzepatide in patients with inadequately controlled type 2 diabetes on diet and exercise alone
SURPASS-2 (NCT03987919) compared tirzepatide to semaglutide in patients with type 2 diabetes
SURPASS-3 (NCT03882970) compared tirzepatide to insulin degludec in patients with type 2 diabetes
SURPASS-4 (NCT03730662) compared tirzepatide to insulin glargine in patients with type 2 diabetes and increased cardiovascular risk
SURPASS-5 (NCT04039503) studied tirzepatide added to insulin glargine with or without metformin in patients with type 2 diabetes.

Additionally, there is a SURPASS-CVOT (NCT04255433) investigating cardiovascular outcomes with tirzepatide.

Dosing and Administration

Both Zepbound and Mounjaro:

Are administered via subcutaneous (under the skin) injection 1 time a week
Are available in the same dose strengths: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, 15mg
Follow identical dose escalation schedules
Use the same injection pen design and technology.

Cost and Insurance Coverage

Zepbound Coverage

Coverage Challenges:

Many insurance plans exclude weight loss medications
Often requires medical necessity documentation
OSA coverage policies can vary depending on your specific insurance plan.

Prior Authorization Requirements:

BMI documentation over 6-12 months
Documented weight loss attempts
Comorbidity documentation
Specialist consultation records.

Mounjaro Coverage

Typical Coverage Pathway:

Covered under diabetes medication benefits
Usually requires type 2 diabetes diagnosis (ICD-10 code)
May need prior authorization showing:
- Previous diabetes medication trials
- Current HbA1c levels
- BMI documentation.

Common Requirements:

Step therapy (trying metformin first)
Prescriber specialization (endocrinologist preferred)
Regular monitoring documentation.

Cost Comparison Zepbound vs. Mounjaro

Without Insurance:

Both medications: $1,000-$1,200 per month
Annual cost: $12,000-$14,400.

Copay Assistance Programs:

Mounjaro Savings Card: $25/month for commercially insured patients
Zepbound Savings Card: $25/month for eligible patients
Income and insurance restrictions apply.

FAQs about Zepbound vs Mounjaro

Is Mounjaro the same as Zepbound?

Yes and no. Mounjaro and Zepbound contain exactly the same active ingredient (tirzepatide) and are identical medications molecularly. However, they have different FDA approvals and are marketed for different purposes:

Mounjaro: FDA-approved for type 2 diabetes
Zepbound: FDA-approved for chronic weight management and obstructive sleep apnea (OSA).

Which is better for weight loss: Mounjaro or Zepbound?

Neither is "better" as they contain the identical active ingredient (tirzepatide) and work exactly the same way in the body. The clinical trials showing 20.9% average weight loss apply to both medications. The choice between them typically depends on:

Primary medical condition (diabetes vs weight management)
Insurance coverage
Cost considerations
Healthcare provider preference.

Can Mounjaro and Zepbound be used together?

No, Mounjaro and Zepbound should never be used together because:

They are the exact same medication (tirzepatide)
Using both would result in double-dosing
This could lead to serious side effects
No additional benefits would be gained.

Why does Eli Lily have two brands of the same drug?

Eli Lilly intentionally created two separate brands for tirzepatide and the dual branding strategy serves several purposes:

Allows for different insurance coverage pathways
Helps healthcare providers prescribe for specific conditions
Enables targeted marketing for different patient populations
Complies with FDA labeling requirements for different indications.

How do insurance companies cover Mounjaro vs Zepbound?

Mounjaro coverage:

Generally covered under diabetes medication benefits
May require proof of type 2 diabetes diagnosis
Might need documentation of previous diabetes medication use
Often requires prior authorization.

Zepbound coverage:

Typically falls under weight management benefits
May require specific BMI criteria
Could need documentation of previous weight loss attempts
Many insurance plans exclude weight loss medications
Not clear if insurance companies will cover for OSA
May require different prior authorization process.

Can I use my diabetes diagnosis to get Zepbound covered?

No, you must use the medication approved for your condition. Using Mounjaro (diabetes-approved) for weight loss or Zepbound (weight-loss-approved) for diabetes may result in coverage denial.

What if I have both diabetes and obesity?

Either medication can be appropriate, but Mounjaro is typically preferred due to its diabetes indication and better insurance coverage pathway.

How long does it take to see results?

Most patients notice appetite suppression within 2-4 weeks, with significant weight loss typically beginning around weeks 8-12.

What happens if I stop taking the medication?

Weight regain is common after discontinuation. Most patients regain 50-80% of lost weight within 1-2 years without continued treatment.

Are there any drug interactions?

Tirzepatide can delay gastric emptying, potentially affecting absorption of oral medications. Adjust timing of other medications as needed, especially:

Oral contraceptives
Warfarin
Digoxin.

Can I drink alcohol while taking this medication?

Alcohol isn't contraindicated, but it may worsen gastrointestinal side effects. Additionally, alcohol can affect blood sugar levels in diabetic patients.

References

Mounjaro Prescribing Information. https://uspl.lilly.com/mounjaro/mounjaro.html#pi
Zepbound Prescribing Information. https://uspl.lilly.com/zepbound/zepbound.html#pi

Ozempic Mounjaro Wegovy & Zepbound: Weight Loss Compared

Ozempic, Mounjaro, Wegovy and Zepbound can all lead to long-term weight loss, but only Wegovy and Zepbound are approved by the FDA for this use. In studies, Zepbound has led to a 21% weight loss in adults using the highest dose, while Wegovy has led to about a 15% weight loss.

Do Ozempic, Wegovy, Mounjaro & Zepbound cause hair loss?

There’s no evidence that hair loss is a direct side effect of Ozempic, Wegovy, Mounjaro or Zepbound. Hair loss is more likely due to the stress of rapid weight loss on your body, which can lead to temporary shedding of hair over several months, a condition known as telogen effluvium. Continue reading

How long does it take for Mounjaro to start working?

Mounjaro (generic name: tirzepatide) will start to lower your blood sugar levels right away but it can take 8 to 12 weeks to reach your target A1C goal. When compared to some other diabetes treatments, studies have shown that it can take 8 weeks to reach an A1C target of ≤7% and 12 weeks to reach an A1C ≤6.5% with Mounjaro. Significant weight loss can occur as early as 28-weeks. Continue reading