Does Mounjaro Cause Weight Loss? A Research Review

Does Mounjaro Cause Weight Loss? A Research Review

| |
| |

Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to weight loss medication.

Mounjaro is a prescription medication that’s FDA-approved for the treatment of type 2 diabetes. The drug is increasingly used off-label for weight loss, and the FDA recently approved a medication for weight loss that uses the same active ingredient as in Moujaro.

The generic form of this drug is called tirzepatide, and we’ll use these terms interchangably trhoughout this article as they refer to the same active drug ingredient.

But is Mounjaro actually proven in clinical studies to cause weight loss? What's the difference between Mounjaro and the drug that was FDA-approved for weight loss? Does Mounjaro cause side effects? And how do real users rate and describe its effects?

In this article we’ll answer all of these questions and more, as we review clinical studies on Mounjaro to determine whether or not it causes weight loss.

We'll explain the difference between Mounjaro and the FDA-approved medication containing the same active drug ingredient, discuss the risk of side effects and feature unsponsored Mounjaro patient reviews.

Does Mounjaro Cause Weight Loss?

Mounjaro was initially studied (and approved) for the treatment of type 2 diabetes, but weight loss was documented as a side effect in some trials.

A clinical trial published in The New England Journal of Medicine analyzed the effectiveness of Mounjaro for weight loss in obese patients.

After 72 weeks, patients on a 5 milligram (mg) weekly dose lost an average of 15% of baseline body weight, patients on a 10 mg weekly dose lost an average of 19.5% of baseline body weight, and patients on a 15 mg weekly dose lost an average of 20.9% of baseline body weight.

These results are significant, and it was also reported that around 90% of patients experienced a weight reduction from baseline body weight of 5% or more.

A patient starting at 200 pounds would end the trial at 170 pounds after a 15% decrease in baseline body weight.

A 2021 clinical trial compared the effects of Mounjaro and semaglutide on diabetes and weight.

As we documented in our semaglutide weight loss reviews article, semaglutide is another type 2 diabetes medication that’s been shown in clinical studies to cause weight loss (and is FDA-approved for weight loss).

Mounjaro was found to be superior to semaglutide for weight loss at all doses.

Given the impressive research on Mounjaro for weight loss, the drug has received “fast track” status from the FDA according to the drug’s manufacturer.

The FDA is currently reviewing the clinical studies on Mounjaro that documented weight loss, and may approve the drug for the treatment of obesity in the future.

Based on the available research we will conclude that Mounjaro is likely effective for causing weight loss in overweight and obese patients.

We would consider weight loss to be a potential secondary benefit of the drug for patients with type 2 diabetes who are also overweight or obese.

A segment on popular media brand Today overviewed some of the research on Mounjaro for weight loss. The video is only 3 minutes long:

Mounjaro vs. Zepbound

Zepbound is the FDA-approved weight loss medication that contains the same active ingredient (tirzepatide) as in Mounjaro.

Interestingly, Zepbound uses the same tirzepatide dose as Mounjaro, making the two medications functionally equivalent. This is unique because FDA-approved medications for different health outcomes typically have different doses.

Mounjaro's FDA label indicates a starting dose of 2.5 mg injected once-weekly, and a maximum dose of 15 mg.

Zepbound's FDA label indicates a starting dose of 2.5 mg injected once-weekly, and a maximum dose of 15 mg. 

Using Mounjaro for weight loss would constitute an off-label use, so even though the medications are functionally similar, we would recommend that patients interested in pharmaceutical weight loss treatment speak with their doctor about Zepbound rather than Mounjaro.

Does Mounjaro Cause Side Effects?

Mounjaro black box warning

Mounjaro’s FDA label has a “black box” warning, shown above, that indicates an increased risk of thyroid C-cell tumors.

This warning is based on data from animal studies, and it’s yet unclear if the drug increases the risk of this type of cancer in humans.

The drug manufacturer recommends that patients with a family history of medullary thyroid carcinoma (a type of thyroid cancer) or multiple endocrine neoplasia type 2 (a rare genetic disorder that can cause tumors in the thyroid gland) avoid use of Mounjaro.

A meta-study published in the Molecules journal documented that the most common side effects of Mounjaro are somewhat mild: nausea, vomiting and diarrhea. 

It’s important that patients speak with their doctor about the risk of these side effects before using Mounjaro.

Real People Try Mounjaro

A YouTube creator named “megan muise” has a video on her experience using Mounjaro for weight loss that has over 45,000 views:

A YouTube creator named Crissy G claims to have lost 42 pounds on Mounjaro, and includes before-and-after images of her weight loss journey:

How Much Does Mounjaro Cost?

We typically recommend that patients speak with their doctor about the generic versions of medications rather than the brand-name versions, because generics should be functionally equivalent and can be much cheaper.

However, at the time of updating this article there isn't a generic version available in the US according to

Mounjaro was only approved by the FDA in 2022, and drug manufacturers often have several years of exclusivity rights.

The cost of Mounjaro will vary significantly based on health insurance coverage.

The drug manufacturer, Lilly, reports that the retail price is currently over $1,000, but patients can apply for a Savings Card or savings coupon at this link to the Savings page on the brand’s website.

The above-linked Savings resource page states that some commercially-insured patients can pay as little as $25 for a 1-month or 3-month Mounjaro prescription.

Our Clean Weight Loss Picks

There are food-based nutrients which have been shown in medical studies to be effective for weight loss.

Dietary fiber was shown in a medical review published in The Journal of Nutrition to cause 16 pounds of weight loss in 6 months when combined with moderate caloric restriction (750 calories per day below baseline).

MBG Organic Fiber Potency+ is our top fiber pick because it's certified organic, provides 7 g of fiber per serving and costs under $1.85 per serving at the time of updating this article.

MCT oil was shown in a meta-study to cause more than one pound of weight loss over 10 weeks. This equates to potential annualized weight loss of 6 pounds per year with less than one tablespoon's worth of MCT oil per day.

Bulletproof MCT Oil is our top MCT oil product, because the only ingredient is MCT oil derived from coconuts. and it currently costs only $15.50 for over a month's worth of product.

Ginger intake "significantly decreased body weight" according to a 2019 meta-study on ginger and weight loss that analyzed data from 14 clinical trials.

Pique La Ginger is our top ginger product, because it's an organic tea in convenient crystallized form, and all that's needed is to pour the powder into a glass and add hot water.

All three of the products mentioned in this section are entirely free of additive ingredients that we consider to be unhealthy.

We are not suggesting that any of the products referenced in this section are as effective as Mounjaro, or any other FDA-approved medication. Rather, we're sharing options that patients with an aversion to pharmaceutical medication may wish to speak to their doctor about.

Patients Rate Mounjaro is a website that allows prescription medication patients to rate and review the drugs they're taking.

We cannot verify the accuracy or authenticity of any reviews on this site.

Monujaro has been reviewed over 200 times for the treatment of obesity on, with an average rating of 8.9 out of 10 at the time of updating this article.

A top positive review comes from a user named "Senagal" who gave the medication a 10/10 rating, and claims to have lost weight while using it:

"I am an African American female 58yrs old 5’8” weighed an unbelievable 270lbs 12/30/22 I asked my doctor could I take this medication and now here we are. 8 weeks later. I currently weigh 244.6 lbs"

A top negative review is written by a user named "Paul" who gave the drug a 1/10 rating, and claims to have experienced severe side effects:

"I seem to have experienced almost every side effect except coma, and if I hadn't stopped taking the drug, I'm certain that my severe jaundice would have put me in a coma. I did lose a significant amount of weight but almost died in the process, and my tachycardia is still presenting..."

Stay up-to-date on our research reviews


The research on Mounjaro for weight loss is promising.

The drug appears to have a similar side effect profile to other prescription, injectable weight loss drugs like semaglutide, but appears to be more effective based on early research.

We do not recommend the use of Mounjaro for weight loss alone, as the drug is currently not approved by the FDA for the treatment of obesity.

We would consider weight loss as a potential secondary benefit of the drug for patients who have type 2 diabetes and are also obese or overweight.

A drug called Zepbound was recently approved by the FDA for weight loss, and it contains the same active ingredient, at the same dose, as Mounjaro.

Mounjaro may increase the risk of thyroid tumors as a rare side effect, but the more common side effects are gastrointestinal such as nausea or diarrhea.

The retail price of Mounjaro is relatively expensive, but the actual price patients will pay depends on their health insurance coverage.

It seems worthwhile for patients interested in this medication to apply for a coupon on the drug manufacturer’s website to see if they qualify for a discount.