Why am I not losing weight on Mounjaro?

If you’re taking Mounjaro® (tirzepatide) to lose weight, what’s going on if your weight loss stalls? Or what if you don’t lose any weight at all? ‍

Mounjaro, a type 2 diabetes medication approved by the U.S. Food and Drug Administration has a remarkable reputation for yielding unprecedented weight loss—and for good reason. The results of a trial funded by Eli Lilly (the drug’s manufacturer) and published in the New England Journal of Medicine (NEJM) found 85% of those on the lowest dose of Mounjaro and 91% on the highest dose lost at least 5% of their total body weight. That five percent is a big deal! According to the Obesity Action Coalition, losing even 5% of one’s body weight can have outsized health benefits including reducing the risk of type 2 diabetes and heart disease. 

Mounjaro can be used off-label, at your provider’s discretion, for weight loss similar to its cousin Zepbound®, which also has the active ingredient tirzepatide. If your provider thinks that you may benefit from Mounjaro for weight loss and diabetes management, your own weight loss journey may be slower to ensure safe blood glucose levels. Found’s providers will work closely with you to determine best steps.

But what if you’re not experiencing the sort of weight loss you’d expected? Rest easy: It’s not your fault. The study’s impressive stats reflect averages—they’re not a crystal-ball prediction of what will work for each individual. And remember, on the flipside, the study found that 9% to 15% of participants lost less than 5% of their total body weight—but that’s not the sort of stat that gets hyped by the media.

Let’s take a look at factors that might impact the medication’s effectiveness for weight loss, as well as potential next steps for building a sustainable weight loss plan.

Factors that can influence weight loss results

The impact of drugs used for weight loss—whether it’s Mounjaro, Wegovy®, Ozempic®, or another prescription medication—varies from person to person. Factors affecting how well a weight loss drug will work for you include genetics, family history, age, hormone status, metabolic adaptation, and the root cause of the obesity. So if you’re asking yourself, “Why aren’t I losing weight on Mounjaro?” we’ve got some answers. 

Personal medical history and medication

Some health conditions and medications can interfere with weight loss. To figure out why you can’t lose weight, working with an obesity medicine expert to evaluate your health status can help reveal whether biological blockers may be playing a role.  

Genetics and phenotypes

Pinpointing your phenotype—determined by your genetic makeup—can help determine which biological factors may be related to weight gain. Weight care experts use phenotypes to inform a patient’s personalized weight management plan. At Found, our MetabolicPrint™ profiles (used to describe your unique phenotype) include Brain-Gut Disconnect, Constant Cravings, Mood Responses, and Slow Metabolism.

Obesity experts can match weight loss medications to specific phenotypes to assist and enhance weight loss. For example, tirzepatide can be a good fit for those with a Brain-Gut Disconnect profile who constantly feel hungry even after eating. It’s a dual receptor agonist drug, and this type of medicine works by imitating two gut peptides that help control blood sugars and slow digestion, which, in turn, causes you to feel fuller longer. However, another pharmaceutical approach may be more suitable if you don’t fit this profile.

Having excess weight (versus obesity)

When it comes to taking tirzepatide to manage excess weight (rather than obesity), the impact is less clear. The 2022 NEJM study, which showed sustained and significant weight loss with tirzepatide, primarily focused on people with obesity, not excess weight (pre-obesity). Of the 2,539 patients, only 5.5% had overweight, as indicated by a body mass index below 30. To determine how safe and effective tirzepatide will be for people with excess weight, further studies are needed. 

Dosage 

Mounjaro is available in weekly, injectable doses ranging from 5 mg to 15 mg (the starting dose is 2.5 mg). The manufacturer, Eli Lilly, recommends generally that people taking Mounjaro ease in, beginning with a 2.5 mg weekly dose for the first four weeks. During weeks five to eight, Lilly suggests the weekly dose dials up to 5 mg. Your health care provider may continue to customize your dose and increase it by 2.5 mg increments at this four week cadence, if a higher dose is clinically necessary for your treatment.

Lifestyle changes

Tirzepatide, under the brand names Mounjaro and Zepbound, is intended to be used with diet changes and regular exercise. So, if you’re taking this medication intending to lose weight but haven’t made these lifestyle changes, this could be a good place to start.

Timing of lifestyle changes

Timing makes a difference, too. Embarking on changes to diet and exercise routines before you start taking tirzepatide can substantially increase the magnitude of weight loss, according to the results of an 84-week randomized, double-blind, placebo-controlled clinical trial. The study, published in Nature Medicine, examined the effects of taking the drug for 72 weeks following an intensive 12-week lifestyle intervention program. The lifestyle interventions included frequent counseling sessions with a dietician, a reduced-calorie meal plan, and at least 150 minutes of moderate-intensity physical activity each week.

Side effects

If you experience severe side effects and decide to stop taking Mounjaro, the weight that you’ve lost can return. Common side effects of receptor agonist medications such as Mounjaro, Wegovy, Ozempic and others include nausea, vomiting, diarrhea, and acid reflux. More serious but less common side effects include pancreatitis, gallbladder disease, and worsening of diabetic eye disease. Those with a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2 shouldn’t use these drugs. Find detailed side effect and risk information for specific medications on our dedicated weight loss medication page..

How to make a personalized weight care plan

Even if one hyped medication doesn’t work for you, you‘ve still got options. With Found, you can count on expert guidance and support in your weight loss journey. A Found membership includes a MetabolicPrint assessment to uncover the root cause of your weight challenges and providers trained in obesity medicine. After a consultation, your clinician will develop a customized weight loss plan and tailor your prescription to work with your specific biology. You’ll find additional support through our in-app behavior change program, health coaching, and the Found community. 

Ozempic and Mounjaro are only FDA-approved to treat type 2 diabetes. Found is not affiliated with Eli Lilly and Co., the owner of the registered trademark Mounjaro and Zepbound, nor is it affiliated with Novo Nordisk A/S., the owner of the registered trademarks Ozempic and Wegovy.‍

About Found

Found is among the largest medically-supported telehealth weight care platforms in the country, having served more than 250,000 members to date. To discover your MetabolicPrint™ and start your journey with Found, take our quiz. GLP-1 prescriptions, filled through your local pharmacy, are now available as part of Found's weight-loss toolkit.

While GLP-1s are effective for weight loss, they are not clinically appropriate for everyone. Eligibility for a GLP-1 is based on a thorough evaluation of your medical history, eating behavior, lab work, and insurance coverage. If a GLP-1 is not appropriate for you, our providers will work with you to determine an effective medication for your health profile. This content does not provide medical advice and does not substitute for a consultation with a doctor or health care provider.