Can You Take Mounjaro and Metformin Together? Yes, and Here’s Why You Might Take Both

Metformin is the most prescribed diabetes medication in the U.S. It’s also one of the safest and most effective medications for diabetes on the market. Because of this, it’s considered a first-choice treatment for many adults and children with Type 2 diabetes.

But what are your options if you’re taking metformin and your blood glucose (sugar) levels aren’t staying in your target range? It’s common to take more than one medication to help meet diabetes treatment goals. And there are many oral and injectable options that can be safely combined with metformin.

Mounjaro (tirzepatide) is an injectable Type 2 diabetes medication that’s grown in popularity over the past few years. But can you take Mounjaro and metformin together? In short, yes. And the combination can be beneficial for many people with Type 2 diabetes.

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What are Mounjaro and metformin’s approved uses?

Both Mounjaro and metformin are FDA approved to help lower blood glucose levels for people with Type 2 diabetes. They both work best when combined with a diabetes-friendly diet and regular exercise. But they are approved for use in different age groups.

Mounjaro is currently only approved for use in adults. There’s an ongoing clinical trial studying its safety and effectiveness in children as young as 10 years old. This study is expected to finish in early 2025. So Mounjaro could be approved for use in kids with Type 2 diabetes some time after that.

On the other hand, metformin is approved for use in adults and children age 10 and older. Until 2023, it was one of the only Type 2 diabetes treatments that was approved for use in kids.

Good to know: Tirzepatide, Mounjaro’s active ingredient, is also approved for chronic weight management in adults. But it’s approved for this use under a different brand name: Zepbound. Mounjaro isn’t an approved weight-loss medication.

Can you take Mounjaro and metformin together?

Yes, most people can safely take Mounjaro and metformin together if needed. Though, people typically try one diabetes medication (commonly metformin) by itself first. If that doesn’t work well enough to lower blood glucose levels, then a prescriber may suggest adding a second medication, which is called combination therapy.

For people who need combination therapy, the American Diabetes Association recommends starting sooner rather than later. This can help lower the risk of diabetes-related complications in the long run.

Mounjaro may be a preferred choice if your diabetes treatment goals include losing weight. As we’ll discuss more below, Mounjaro can promote significant weight loss for many people.

How are Mounjaro and metformin taken?

One main difference between metformin and Mounjaro is the way they’re taken.

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Metformin is most commonly taken as oral tablets, though an oral solution is also available. Metformin comes in two forms:

1. An immediate-release form, which is typically taken 1-3 times daily with meals

2. An extended-release form, which is typically taken once a day with an evening meal

You’ll likely start with a lower metformin dosage and slowly increase it as needed to help limit side effects.

Mounjaro, on the other hand, is a once-weekly injection that’s given at home. It’s available as prefilled injection pens and single-use vials. You’ll start with the lowest Mounjaro dosage (2.5 mg once a week) and gradually raise it over several weeks. This helps to minimize side effects while your body adjusts to the medication.

What are the benefits of taking Mounjaro and metformin together?

The biggest benefit of taking Mounjaro and metformin together is that you may achieve lower blood glucose levels than you would taking either by itself. And over time, better glucose balance can help lower your risk of diabetes-related complications, such as nerve or kidney damage.

Mounjaro and metformin are both effective diabetes medications. They can help lower your blood glucose levels and hemoglobin A1C (HbA1c or A1C). Your A1C is your average glucose level over a 3-month period.

When taken without other diabetes medications, metformin can reduce a person’s A1C by up to 1.5%. But when Mounjaro was added to metformin in clinical trials, people experienced an additional 2% A1C reduction. Researchers also found that over 85% of trial participants using Mounjaro reached an A1C of less than 7% — a common goal for many people with Type 2 diabetes.

Can you lose weight taking both Mounjaro and metformin?

While neither Mounjaro nor metformin are FDA approved as weight-loss medications, losing weight is a potential side effect of both.

In fact, one of the reasons Mounjaro has made headlines is because of this potential for losing weight. Many people have lost significant weight while using it. In clinical trials, people with Type 2 diabetes that were considered overweight or obese lost up to 15% of their starting body weight after using Mounjaro for 72 weeks (about 16.5 months).

This is what led to tirzepatide, Mounjaro’s active ingredient, being approved as a weight-loss medication under the brand name Zepbound.

Metformin is generally considered a “weight neutral” medication. This means it doesn’t usually cause noticeable weight changes. But in some studies, people have experienced a modest decrease in body weight while taking it. One of these studies noted an average weight loss of 4 to 5 lbs in participants who took metformin for 1 year.

What side effects can happen while taking Mounjaro and metformin together?

When taken separately, Mounjaro and metformin can both cause gastrointestinal (GI) side effects. So it makes sense that you may experience these side effects if you’re taking them together. Common examples include nausea or vomiting, diarrhea, and stomach pain. If you experience GI side effects, your symptoms will likely improve as your body adjusts to the medication(s).

Another potential side effect that’s listed in both Mounjaro’s and metformin’s labeling is hypoglycemia (low blood glucose). But this is extremely rare with both medications — even if you’re taking them together.

Your risk of low blood glucose may be higher if you’re also taking other diabetes medications, such as insulin and sulfonylureas. Be sure to discuss these risks with your diabetes care team. They may make dosage adjustments to one or more of your medications to help you avoid low blood glucose.

There are also rare but serious side effects that are unique to each of these medications. These include:

• Lactic acidosis (metformin)

• Vitamin B12 deficiency (metformin)

• Inflammation of the pancreas, also called pancreatitis (Mounjaro)

• Gallbladder problems (Mounjaro)

• Certain thyroid cancers seen in animal studies (Mounjaro)

Keep in mind, this isn’t a list of all potential side effects for Mounjaro or metformin. Your prescriber or pharmacist can provide you with more detailed information for either medication.

Who should not combine Mounjaro and metformin?

Mounjaro and metformin are safe, effective medications for many people living with Type 2 diabetes. But there are situations in which one or both medications may not be right for you. For instance, if you’re already meeting your treatment goals with one diabetes medication, it’s unlikely that your prescriber will suggest you take another.

You shouldn’t take Mounjaro if:

• You have a personal or family history of medullary thyroid cancer

• You have a history of multiple endocrine neoplasia syndrome type 2 (MEN 2)

• You’re taking a medication similar to Mounjaro, such as Ozempic (semaglutide), Victoza (liraglutide), or Trulicity (dulaglutide)

You shouldn’t take metformin if:

• You have moderate-to-severe kidney disease

• You’re experiencing sudden or chronic metabolic acidosis (an acid-base imbalance in the body), including diabetic ketoacidosis

If taking Mounjaro and metformin together isn’t right for you, don’t fret. There are many other options available for combination therapy. Your diabetes care team can help you find the best choice for you.

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Written by:

Kristina D. Carter, PharmD, MBA, MHA

Kristina D. Carter, PharmD, MBA, MHA, has over 25 years of experience working in healthcare. She is registered as a licensed pharmacist in Georgia, Indiana, and Tennessee.

Reviewed by:

Farah Naz Khan, MD

Farah Naz Khan, MD, is a board-certified physician at the UW Medicine Diabetes Institute and a clinical assistant professor of metabolism, endocrinology, and nutrition at the University of Washington.

Reviewed by:

Sophie Vergnaud, MD

Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. An experienced and dedicated pulmonologist and hospitalist, she spent a decade practicing and teaching clinical medicine at academic hospitals throughout London before transitioning to a career in health education and health technology.

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