June 7, 2022

Mounjaro vs. Zepbound for Weight Loss: What Patients Should Know

Mounjaro® and Zepbound® are often discussed as if they were different weight-loss medications. Both are manufactured by Eli Lilly and contain the same active ingredient, tirzepatide. They work through the same GIP and GLP-1 receptors and are administered as once-weekly injections.

The principal difference is what each brand is FDA-approved to treat. Mounjaro is approved for type 2 diabetes and certain cardiovascular-risk reduction in adults with type 2 diabetes. Zepbound is the tirzepatide brand approved specifically for long-term weight reduction in qualifying adults.

Understanding this distinction can help patients have better-informed conversations with their healthcare providers and insurance companies.

What Is Mounjaro?

Mounjaro is a prescription medication containing tirzepatide. The FDA has approved it, together with diet and exercise, to improve blood-sugar control in adults and children age 10 and older with type 2 diabetes.

Mounjaro is also approved to reduce the risk of major cardiovascular events, including cardiovascular death, nonfatal heart attack and nonfatal stroke, in adults with type 2 diabetes who are at high risk for these events.

Patients taking Mounjaro for diabetes may also lose weight. However, Mounjaro is not the tirzepatide brand specifically approved for chronic weight management.

A healthcare provider may sometimes prescribe an approved medication for a purpose that is not included in its FDA labeling. This is known as off-label prescribing. Whether off-label treatment is appropriate must be determined individually by a qualified medical provider.

What Is Zepbound?

Zepbound contains the same active ingredient as Mounjaro: tirzepatide. Unlike Mounjaro, Zepbound is FDA-approved for long-term weight reduction and weight maintenance in qualifying adults.

Zepbound may be prescribed, along with a reduced-calorie diet and increased physical activity, for adults who have:

• A body mass index of 30 or higher, which is classified as obesity
• A body mass index of 27 or higher, which is classified as overweight, and at least one weight-related medical condition

Zepbound is also approved to treat moderate to severe obstructive sleep apnea in adults with obesity.

A medical consultation is necessary to determine whether a patient meets the eligibility requirements and whether tirzepatide is an appropriate treatment option.

What Is the Difference Between Mounjaro and Zepbound?

Although Mounjaro and Zepbound contain the same active ingredient, they have different FDA-approved indications and may be treated differently by insurance companies.

Feature	Mounjaro	Zepbound
Active ingredient	Tirzepatide	Tirzepatide
Primary FDA-approved use	Type 2 diabetes	Long-term weight reduction
Additional approved use	Cardiovascular-risk reduction in certain adults with type 2 diabetes	Moderate to severe obstructive sleep apnea in adults with obesity
Administration	Once-weekly injection	Once-weekly injection
Insurance consideration	Generally evaluated under diabetes benefits	Generally evaluated under weight-management or obesity-treatment benefits

Patients should not assume that Mounjaro and Zepbound are interchangeable for prescribing or insurance purposes simply because they contain the same active ingredient.

Is Mounjaro or Zepbound Better for Weight Loss?

Mounjaro and Zepbound contain the same medication, so Zepbound is not a stronger version of tirzepatide. Zepbound is the brand studied and approved specifically for chronic weight management.

In the 72-week clinical trial described in the Zepbound prescribing information, adults with obesity or overweight who did not have type 2 diabetes received lifestyle counseling plus Zepbound or a placebo.

Average weight reduction was:

• 15.0% with the 5 mg dose
• 19.5% with the 10 mg dose
• 20.9% with the 15 mg dose
• 3.1% with the placebo

These percentages are clinical-trial averages and do not predict or guarantee an individual patient’s results. Outcomes vary according to the dose reached, treatment duration, medical conditions, medication tolerance, nutrition, physical activity and adherence. Patients with type 2 diabetes had lower average weight reductions in a separate trial.

Patients can learn more about tirzepatide and other injectable options on our GLP-1 weight-loss treatment page.

How Does Tirzepatide Work?

Tirzepatide activates receptors for two hormones involved in appetite, digestion and blood-sugar regulation:

• Glucose-dependent insulinotropic polypeptide, or GIP
• Glucagon-like peptide-1, or GLP-1

Tirzepatide can help patients feel full sooner and remain full longer, which may reduce calorie intake. It also delays gastric emptying and affects how the body regulates blood sugar.

Medication selection should not be based only on which drug appears to produce the highest average weight loss. The patient’s health, medical history, current medications, treatment goals and ability to tolerate treatment must also be considered.

What Are the Common Side Effects of Tirzepatide?

Common side effects reported with Zepbound include:

• Nausea
• Diarrhea
• Vomiting
• Constipation
• Abdominal pain or indigestion
• Injection-site reactions
• Fatigue
• Burping or acid reflux
• Hair loss associated with weight reduction

Digestive symptoms may be more noticeable when treatment begins or after the dose is increased. Patients should contact their provider if symptoms are persistent or severe.

Altered or painful skin sensation, known as dysesthesia, was uncommon in Zepbound weight-management trials. It occurred in 0.2% of patients receiving 5 mg or 10 mg and 0.4% receiving 15 mg, compared with 0.1% receiving a placebo.

Who Should Not Use Tirzepatide?

Tirzepatide has a boxed warning concerning thyroid C-cell tumors observed in rats. It is unknown whether tirzepatide causes these tumors in humans.

Mounjaro and Zepbound should not be used by patients with:

• A personal or family history of medullary thyroid carcinoma
• Multiple Endocrine Neoplasia syndrome type 2, also called MEN 2
• A previous serious allergic reaction to tirzepatide or the product’s ingredients

Additional warnings and precautions include pancreatitis, gallbladder disease, severe gastrointestinal reactions, dehydration-related kidney injury, serious allergic reactions and low blood sugar, particularly when tirzepatide is used with insulin or certain diabetes medications.

Patients with a history of pancreatitis require careful medical evaluation. Severe or persistent abdominal pain, especially pain that radiates to the back or occurs with vomiting, requires prompt medical attention.

Patients should tell their healthcare team that they take tirzepatide before any surgery or procedure requiring general anesthesia or deep sedation.

Zepbound should be discontinued when pregnancy is recognized. Patients who are pregnant, planning pregnancy or breastfeeding should discuss treatment and available alternatives with their healthcare provider.

Zepbound should not be used with Mounjaro, another tirzepatide-containing product or another GLP-1 receptor agonist.

Testing and Monitoring

Medical evaluation is an important part of selecting and monitoring prescription weight-loss treatment. At MD Wellness Center & Med Spa, evaluation may include laboratory testing based on the patient’s medical history, symptoms, current medications and risk factors.

Follow-up testing and monitoring are individualized according to the medication prescribed, treatment response and the patient’s medical needs. Patients should report persistent digestive symptoms, symptoms of dehydration, changes in vision or other concerning side effects to their provider.

Will Insurance Cover Mounjaro or Zepbound?

Insurance coverage varies. A health plan may cover Mounjaro for a patient with type 2 diabetes but exclude medications prescribed specifically for weight management. Other plans may cover Zepbound when the patient meets the plan’s eligibility and prior-authorization requirements.

Patients should contact their insurer to verify:

• Whether the prescribed product is covered
• Which diagnoses qualify for coverage
• Whether prior authorization is required
• Whether step therapy or other requirements apply
• The expected out-of-pocket cost

Coverage rules can change, so benefits should be confirmed directly with the insurance company.

For patients without insurance coverage for obesity medication, Lilly offers self-pay access to Zepbound through LillyDirect. When medically appropriate, Dr. Kesa can send a Zepbound prescription to LillyDirect for eligible patients seeking self-pay home delivery. The GLP-1 medications offered through our clinic are selected individually based on each patient’s medical evaluation and treatment needs. Eligibility, available products, pricing, and program terms are determined by Lilly and may change.

Why Medical Supervision Matters

Tirzepatide is a prescription medication and is not appropriate for everyone. Medical supervision includes reviewing the patient’s weight and health history, current medications, possible interactions, treatment goals, side effects and progress.

The treatment plan may also include nutrition, physical activity and strategies for maintaining weight loss over time. Medication type, dosage, monitoring and any combination with another class of weight-loss medication must be determined individually.

MD Wellness Center & Med Spa offers in-office medical weight loss in Indianapolis and virtual weight-loss consultations for qualifying Indiana residents.

Patients who want to understand other available prescription options can visit our medically supervised weight-loss medication page.

Schedule a Medical Weight-Loss Consultation

Choosing a weight-loss medication requires an individualized medical evaluation. Dr. Srinivasu Kesa is board-certified in Obesity Medicine and has more than 30 years of clinical experience. He develops treatment plans based on each patient’s health history, current medications, treatment goals and response to care.

MD Wellness Center & Med Spa serves Indianapolis, Carmel, Fishers, Noblesville, Greenwood, Westfield and surrounding communities. Virtual consultations are available to qualifying Indiana residents.

Schedule a medical weight-loss consultation or call 317-548-4666 to discuss available options.

This article provides general educational information and is not medical advice. Treatment eligibility, medication selection, testing and monitoring must be determined by a qualified healthcare provider. Individual results vary.

Sources

• FDA prescribing information for Mounjaro
• FDA prescribing information for Zepbound
• Lilly information about Zepbound self-pay access