Zepbound vs. Mounjaro: What’s the Difference?

You may have heard people talking about the medications Zepbound® and Mounjaro® for weight loss or type 2 diabetes treatment. But do you know the difference between Zepbound versus Mounjaro?

Both medications contain the active ingredient tirzepatide and are made by the same pharmaceutical company, Eli Lilly. The biggest difference between Zepbound and Mounjaro is what each one is FDA-approved to treat.

Zepbound is approved by the U.S. Food and Drug Administration (FDA) to help with weight loss in those with obesity or overweight with one or more weight-related conditions. Mounjaro is FDA-approved to help with blood sugar control in people with type 2 diabetes, but it’s sometimes prescribed off-label for weight loss.

For best results and long-lasting weight management, tirzepatide should be paired with healthy lifestyle habits, like nutritious eating and exercise.

Let’s take a deeper look at Zepbound versus Mounjaro.

Zepbound and Mounjaro are two brand names for medications containing the active ingredient tirzepatide.

Eli Lilly manufactures both drugs, and currently, no generic version of the medication is available.

Although Zepbound and Mounjaro contain the same active ingredient, they’re FDA-approved to treat different conditions.

Zepbound is FDA-approved for weight loss in people who have obesity or overweight and one or more weight-related complications. This drug is usually prescribed along with a healthy eating plan and increased physical activity.

Zepbound is sometimes prescribed off-label to treat obstructive sleep apnea. Off-label means a drug is prescribed for something other than the condition it’s FDA-approved for.

Mounjaro is FDA-approved to improve blood sugar control in people with type 2 diabetes. But it’s sometimes used off-label as a weight loss drug.

The active ingredient in Zepbound and Mounjaro is classified as a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide 1 (GLP-1) agonist receptor. So basically, it targets both hormones.

GIP and GLP-1 are incretins — hormones made by the gut. These incretins stimulate insulin release from the pancreas to lower blood sugar levels and reduce appetite. A medication containing tirzepatide mimics the function of these two hormones.

Tirzepatide also increases levels of adiponectin, a hormone primarily produced by fat tissue that helps regulate blood glucose levels by enhancing insulin sensitivity. This effect is another reason tirzepatide is so effective at controlling type 2 diabetes and supporting weight loss.

Zepbound and Mounjaro contain the same active ingredient, but they’re technically not the same drug. The main difference is that Zepbound is FDA-approved for weight loss, while Mounjaro is approved for type 2 diabetes. But Mounjaro may also be prescribed off-label for weight loss.

There are essentially no differences between Zepbound and Mounjaro besides the names they’re sold under and what they’re FDA-approved to treat. Even the doses are usually similar, with a maximum of 15 milligrams (mg) weekly.

Zepbound is FDA-approved for weight loss for people who have obesity or overweight with at least one weight-related health condition.

Healthcare professionals use BMI to get an idea of a person’s body composition and see what weight range they fall into (underweight, normal/healthy weight, overweight, or obesity). The calculation is a ratio of your body weight in kilograms divided by the square root of your height in meters.

You can crunch your own numbers with our BMI calculator.

A BMI over 30 is considered obesity. A BMI of 25 or higher is considered overweight. Although this scale can give medical providers a general idea of who may be at risk for weight-related health complications, it’s not perfect.

Folks with more muscle than average, such as athletes, may be considered overweight on this scale, even if they have a low body fat percentage. And a person with a BMI considered overweight could be in better overall health than someone with a lower BMI.

Besides BMI, your provider will look at your medical history and current health to see if you qualify for Mounjaro or Zepbound.

People with a BMI over 27 might be candidates for Zepbound if they have a weight-related condition such as:

• High blood pressure (hypertension)

• Dyslipidemia, abnormally high levels of fats in your blood

• Type 2 diabetes

• Obstructive sleep apnea

• Cardiovascular disease

Though Mounjaro is only FDA-approved to treat type 2 diabetes, it’s often prescribed off-label for weight loss in situations when Zepbound isn’t available.

We should note that neither medication has been studied or approved for treating type 1 diabetes, and they’re not meant to be used for weight loss for people with a starting BMI under 25.

Research suggests that tirzepatide can be effective for weight loss when combined with a healthy diet and exercise.

In a clinical trial sponsored by Eli Lily, researchers looked at the effectiveness of tirzepatide in 2,539 adults with a BMI over 30 or over 27 with weight-related complications (excluding diabetes).

Study participants received one of these:

• 5 milligrams of tirzepatide

• 10 milligrams of tirzepatide

• 15 milligrams of tirzepatide

• A placebo

They used tirzepatide or a placebo for 72 weeks, including a 20-week period where the dose was deescalated.

At week 72, the average weight loss was:

• 15 percent for the 5-milligram group

• 19.5 percent in the 10-milligram group

• 20.9 percent in the 15-milligram group

• 3.1 percent for the placebo group

The portion of participants who lost at least five percent of their body weight was:

• 85 percent for the 5-milligram group

• 89 percent in the 10-milligram group

• 91 percent in the 15-milligram group

• 35 percent for the placebo group

The average body weight at the beginning of the study was 231 pounds, and the average BMI was 38.0.

The most common side effects for Zepbound or Mounjaro (that happen to more than five percent of people taking them) include:

• Nausea

• Diarrhea

• Vomiting

• Constipation

• Abdominal pain

• Upset stomach

• Injection site reactions

• Fatigue

• Hypersensitivity reactions

• Belching

• Hair loss

• Gastroesophageal reflux disease (GERD)

Serious complications that have been reported in clinical trials include:

• Severe gastrointestinal reactions

• Acute kidney injury

• Acute gallbladder disease

• Acute pancreatitis

• Allergic reaction

• Hypoglycemia

• Diabetic retinopathy complications

• Suicidal behavior or ideation

Both medications have an FDA black box warning for thyroid C-cell tumors. A black box warning is the highest warning from the FDA.

Tirzepatide has been linked to thyroid C-cell tumors in rat studies. It’s unclear if the medication causes an increased risk of thyroid cancer in humans.

There’s no evidence that tirzepatide causes thyroid tumors in humans. Still, it’s generally not recommended for those with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.

Other people who shouldn’t take Zepbound or Mounjaro include:

• Those with severe gastrointestinal disease

• Pregnant people due to a lack of data on its safety

• Individuals with a history of a serious reaction to Zepbound or Mounjaro or any of the medications’ non-medical ingredients

It’s a good idea to discuss any health conditions you have that may impact your eligibility for tirzepatide with your healthcare provider.

Tirzapatide is currently a second-line treatment for diabetes, similar to other drugs like semaglutide. Second-line means your provider may recommend it if the first treatment isn’t effective.

The diabetes medication metformin is generally the first-line treatment option.

Mounjaro is administered as an injection. It comes as a clear or slightly yellowish liquid medication in a single-dose pen with strengths ranging from 2.5 to 15 milligrams.

You can make the injection in your lower abdomen, thigh, or upper-arm, and the injection site can be rotated each time to prevent bruising or infection. Mounjaro can be taken at any time of day, with or without meals.

Mounjaro Dosage

The recommended starting dose of Mounjaro is 2.5 milligrams injected subcutaneously once a week. After four weeks, the dose can be increased to 5 milligrams.

If you need additional blood sugar control, your provider might recommend increasing the weekly dose up to 15 milligrams.

The medication Zepbound is also available as a once-weekly injection. The subcutaneous injection can be made in the same locations as Mounjaro (abdomen, upper-arm, or thigh).

Zepbound Dosage

The recommended starting dose of Zepbound is 2.5 milligrams injected subcutaneously once a week.

The weekly dose can be increased to 5 milligrams, and, if needed, it might continue to be gradually increased up to 15 milligrams. The recommended maintenance dosages for Zepbound are 5, 10, or 15 milligrams once weekly.

Insurance providers often don’t cover anti-obesity drugs, but some plans may cover medications for treating type 2 diabetes.

According to the Mounjaro website, people eligible for the Mounjaro Savings Card might pay as little as $25 for a one-month or three-month prescription. To be eligible, you need to have commercial insurance coverage, and government beneficiaries like Medicare are excluded.

Besides Mounjaro versus Zepbound, there are other GLP-1 medications to consider.

Semaglutide is another medication that’s FDA-approved for helping people with type 2 diabetes control their blood sugar levels or for chronic weight management.

Three brands of semaglutide are available in the United States from the manufacturer Novo Nordisk:

• Wegovy®

• Rybelsus®

• Ozempic®

Of these three, only Wegovy is FDA-approved for weight loss. The other two brands are sometimes prescribed off-label for this purpose. Rybelsus is taken as an oral medication, while the other two are injections.

Semaglutide falls into a class of medications called GLP-1 receptor agonists. It has a similar action as tirzepatide, except it doesn’t mimic GIP.

In a study supported by Eli Lily, researchers compared the effectiveness of tirzepatide and semaglutide for weight loss and managing type 2 diabetes.

They found that the medications offered similar benefits but that tirzepatide was superior for both blood sugar control and weight loss.

Here’s what to keep in mind when deciding between Zepbound versus Mounjaro:

• Both contain tirzepatide. Zepbound and Mounjaro are two medications containing the active ingredient tirzepatide, and both are produced by Eli Lilly.

• They’re FDA-approved for different things. Zepound is approved to help with chronic weight management. Mounjaro is approved for folks with type 2 diabetes to help control blood sugar levels. But either may be prescribed off-label to treat the other condition.

• You have to qualify and get a prescription for either medication. Your healthcare provider can advise you on whether you may benefit from either weight loss medication. They can also help you figure out if you have a condition affecting your eligibility.

Interested in compounded GLP-1 medication for weight loss or diabetes management? Get started today with our quick online weight loss assessment.