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Prescription weight loss that puts you first
Reviewed by Craig Primack, MD, FACP, FAAP, FOMA
Written by Vanessa Gibbs
Published 04/05/2024
Updated 09/23/2024
Trying to lose weight can be confusing, with so many different tips and diets out there. And that’s even before you throw in weight loss drugs.
To make things a little less confusing, we’re here with all the info you need about the popular diabetes drug Mounjaro.
The TL;DR here is that Mounjaro is a type 2 diabetes drug that’s prescribed “off-label” for weight loss. It can help those who are overweight or have obesity lose significant amounts of weight, but it’s not without its risks and side effects.
Below, we cover everything you need to know about Mounjaro, including how it works, dosage and side effects.
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Mounjaro, which is one brand name for the drug tirzepatide, is approved by the U.S. Food and Drug Administration (FDA) as a diabetes drug. It’s also sometimes prescribed off-label for weight loss.
When it comes to weight loss, Mounjaro can help those with and without type 2 diabetes lose weight.
In clinical trials sponsored by Eli Lily, doses of 5 milligrams (mg) to 15mg of tirzepatide can help those with type 2 diabetes lose up to 15 percent of their body weight, and those without type 2 diabetes lose up to 21 percent of their body weight.
Is Mounjaro approved for weight loss? Nope. It’s FDA-approved as a diabetes drug to help people with type 2 diabetes better manage their blood sugar levels.
However, it can help people lose weight. That’s why It’s also prescribed “off-label” for weight loss, which is when a drug is prescribed for something that it isn’t approved for.
One thing to know is that another drug called Zepbound contains the same active ingredient as Mounjaro — tirzepatide — and is FDA-approved for weight loss.
For weight loss, Mounjaro may be prescribed off-label for those with a body mass index (BMI) of 30 or more or 27 or more with at least one weight-related condition, such as high blood pressure, type 2 diabetes, obstructive sleep apnea or cardiovascular disease.
There are a few groups of people who shouldn’t take Mounjaro.
First, anyone who has a family history of medullary thyroid carcinoma or who has multiple endocrine neoplasia syndrome type 2 shouldn’t take Mounjaro.
Anyone who’s had a severe allergic reaction to tirzepatide or any of the inactive substances in Mounjaro should also avoid the drug.
Inactive substances in Mounjaro include:
Sodium chloride
Sodium phosphate dibasic heptahydrate
Hydrochloric acid solution
Sodium hydroxide solution
Mounjaro works for weight loss in a few different ways.
The drug’s active ingredient, tirzepatide, is a glucose-dependent insulinotropic polypeptide (GIP) receptor agonist and a glucagon-like peptide-1 (GLP-1) receptor agonist.
In less-sciencey speak, Mounjaro mimics the GIP and GLP-1, hormones secreted in the intestines.
In clinical trials, Mounjaro and Zepbound led to reduced appetite and increased satiety (feeling full). They may also increase lipolysis, which is the breakdown of fats for energy, among other things.
In short, taking Mounjaro might make you feel less hungry, leading to you eating fewer calories and losing weight.
A 2023 systematic review that contains data from clinical trials looked at 10 studies that included a total of almost 10,000 participants. It concluded that tirzepatide, in doses of 5mg, 10mg and 15mg, was more effective than other drugs in reducing body weight, including other GLP-1 receptor agonists.
Technically, there isn’t a usual dosage of Mounjaro for weight loss, as it’s only approved as a diabetes drug. However, based on the dosage schedule for Zepbound, here’s what a Mounjaro dosage could look like:
A healthcare provider will get you started on a weekly dose of 2.5mg.
After four weeks, you’ll increase this to a 5mg weekly dose.
If needed, your dose could increase in 2.5mg increments, up to a maximum dose of 15mg. You’ll spend four weeks on each dose before increasing it again.
If you can tolerate the higher doses of Mounjaro, they seem to be more effective for weight loss.
A 2022 study sponsored by Eli Lilly looked at the effects of tirzepatide. Participants had a BMI of 30 or more or a BMI of 27 or more with one weight-related health condition that wasn’t diabetes.
They took a once-weekly injection of 5mg, 10mg or 15mg of tirzepatide or a placebo for 72 weeks. That included 20 weeks to increase the dose slowly.
At the end of the experiment, the average percentage change in weight was:
15 percent for those taking 5mg of tirzepatide
19.5 percent for those taking 10mg of tirzepatide
20.9 percent for those taking 15mg of tirzepatide
3.1 percent for those on the placebo
So, the higher the dose of Mounjaro you take, the better your weight loss results may be. A healthcare provider can work with you to find your best Mounjaro dose for weight loss and tell you when to increase your dose.
The common side effects of Mounjaro include:
Nausea
Vomiting
Diarrhea
Constipation
Abdominal pain
Dyspepsia (indigestion)
Decreased appetite — you’re probably looking for this one if you’re taking Mounjaro for weight loss
Side effects may be dose-dependent, meaning higher doses come with a higher risk of some side effects.
There are a few more serious side effects to watch out for.
Potential serious side effects of Mounjaro include:
Pancreatitis (inflammation of the pancreas)
Hypoglycemia (low blood sugar), when used with insulin secretagogues or insulin
Hypersensitivity reactions
Acute kidney injury
Severe gastrointestinal disease
Diabetic retinopathy complications in those with a history of this eye disease
Acute gallbladder disease
Mounjaro also comes with a black box warning stating that tirzepatide causes thyroid C-cell tumors in rats. For now, it’s unclear whether tirzepatide causes these tumors in humans.
Mounjaro is a subcutaneous (under the skin) injection. You inject it into your upper arm, stomach or thigh once a week, rotating the injection site with each dose.
There’s no real best time of day to take Mounjaro. You can take the drug at any time of day, with or without meals.
If you take Mounjaro, you should also prioritize a nutritious meal plan and increased movement. What this looks like will depend on your individual needs, so your prescribing doctor can give you more advice on building healthy lifestyle habits.
If you miss a dose of Mounjaro, don’t panic. Administer the injection as soon as you remember, as long as it’s within four days of your usual injection day.
If it’s been more than four days, skip the missed dose and take your next dose on your usual injection day.
Mounjaro is a prescription drug. If you’re looking into Mounjaro for weight loss, your first step is to talk to a healthcare professional about weight loss medications.
They can determine whether Mounjaro — or another weight loss drug or treatment — is suitable for you and write you a prescription if appropriate.
A healthcare provider may recommend Zepound instead of Mounjaro, especially if you don’t have type 2 diabetes. It may come down to the availability of the drugs and whether you have any pre-existing health conditions.
Mounjaro isn’t usually covered by health insurance when taken for weight loss.
Costs can vary and can add up, especially because you may take Mounjaro for an extended period.
For a rough idea, Mounjaro can cost $1000 to $1100 per month without insurance.
If those figures gave you sticker shock, know there are more affordable weight loss treatments. For example, our comprehensive weight loss programs start at $79 per month.
More research is needed to know exactly what happens when you stop taking Mounjaro, as it’s still a relatively new drug.
You may notice an increased appetite since the drug no longer suppresses your hunger. In addition, any side effects you were experiencing may clear up.
You may also regain some of the weight you’ve lost on the drug, but more studies are needed on this front. Research sponsored by Novo Nordisk shows people may regain two-thirds of the weight they lost one year after stopping semaglutide, but it’s not clear if the same would happen with tirzepatide.
You shouldn’t suddenly stop taking Mounjaro without consulting a healthcare provider first. That doesn’t mean you must keep taking it if side effects are giving you trouble or if you want to stop for another reason. It just means you need to talk to a healthcare provider to get the best advice on how and when to stop taking Mounjaro if you want to quit.
If you experience a severe reaction, however, stop taking Mounjaro immediately and seek medical advice.
You should also stop taking Mounjaro immediately and seek medical advice if you have stomach pain that won’t go away, with or without vomiting. This could be a sign of pancreatitis.
Mounjaro is just one of your weight loss medication options.
You’ve got other injections, such as:
Zepbound (tirzepatide)
Ozempic (semaglutide)
Wegovy (semaglutide)
Saxenda® (liraglutide)
Victoza® (liraglutide)
There are also weight loss medications that don’t involve a needle, such as:
Rybelsus® (semaglutide)
Contrave® (naltrexone-bupropion)
Qsymia® (phentermine-topiramate)
Xenical® (orlistat)
Topamax® (topiramate)
A healthcare provider can walk you through the pros and cons of each medication and help you decide which one may be most suitable for you.
No matter which you choose, you should use weight loss medications in conjunction with drug-free interventions like healthy eating plans, increased movement and behavior change tools. These are all crucial tools to help you on your weight loss journey.
Mounjaro can help people with type 2 diabetes or those who are overweight or have obesity lose weight. But is it for you?
Here’s the final recap:
Mounjaro isn’t FDA-approved for weight loss. It’s approved as a diabetes drug and prescribed off-label for weight loss. Zepbound has the same active ingredient and is FDA-approved for weight loss.
Gastrointestinal side effects are common. Expect GI issues like nausea, vomiting and diarrhea. The silver lining here is that side effects should clear up on their own soon.
Your dose will start low and slowly increase. Your prescribing doctor can give you all the details, but you might get started on a 2.5mg weekly dose and slowly bump that up to a max of 15mg.
One of the most important things to know? Mounjaro isn’t your only option if you’re looking into weight loss treatments. There are other injectables, weight loss pills and drug-free interventions to suit every kind of body and every kind of weight loss journey.
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