How does Mounjaro Work for Weight Loss?
Mounjaro helps weight loss by reducing your appetite and making you feel fuller for longer, which decreases how much food you eat.
Mounjaro works like two natural hormones in our bodies that help control appetite, blood sugar levels, and digestion; they are called GLP-1 and GIP.
When Mounjaro binds to GIP and the GLP-1 receptors, you feel less hungry, it slows the rate food passes through your body, causes the pancreas to release more insulin, and lowers the amount of sugar your liver makes, which helps you lose weight and helps control blood sugar levels.
Mounjaro is a GIP and GLP-1 receptor agonist. Mounjaro works (mechanism of action) by activating both GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) hormone receptors.
Mounjaro is a prescription medication that is given as a once-weekly injection under the skin (subcutaneously) using an autoinjector pen.
Does Mounjaro work for weight loss?
Yes, Mounjaro does work for weight loss. The average Mounjaro weight loss was 16.1 kg (35.5 lb) after 72 weeks on a 5mg weekly dose, 22.2 kg (48.9 lb) on Mounjaro 10mg weekly dose, 23.6 kg (52.0 lb) on 15mg weekly dose, compared to patients who used a placebo lost 2.4 kg (5.3 lb) over the 72 weeks. These results are from the 72-week clinical trial (SURMOUNT-1, NCT04184622) using tirzepatide for weight loss in adults with obesity. Individual results may vary.
Is Mounjaro (tirzepatide) approved for weight loss?
Mounjaro (tirzepatide) is not approved for weight loss by the FDA; it is approved for type 2 diabetes in adults when used together with diet and exercise. The tirzepatide brand FDA-approved for weight loss is Zepbound.
Zepbound (tirzepatide) is FDA-approved for weight loss in adults with obesity or who are overweight and have weight-related medical problems.
Mounjaro vs Zepbound
Mounjaro and Zepbound contain the same active ingredient, tirzepatide, and are both made by Eli Lilly and Company.
They are both available as single-dose pens and single-dose vials in the same strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 12.5 mg, and 15 mg per 0.5 mL.
Does Mounjaro cause stomach side effects?
The most common Mounjaro side effects are stomach related such as nausea, diarrhea, and decreased appetite.
Side effects reported in at least 5% of patients include:
- nausea
- diarrhea
- decreased appetite
- vomiting
- constipation
- indigestion (heartburn)
- stomach (abdominal) pain
While these side effects may be temporary in some patients, they may also affect your appetite.
- In studies, stomach side effects were reported in 37.1% to 43.6% of patients and appeared to be dose-related, compared to 20.4% of patients receiving a placebo (inactive agent).
- The percentage of patients receiving Mounjaro who discontinued treatment due to stomach side effects ranged from 3% to 6.6% of patients receiving Mounjaro, compared to 0.4% in the placebo group.
Related questions
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- Zepbound vs. Mounjaro: Comparison Guide for Weight Loss and Diabetes Treatment
Does Insurance or Medicare cover Mounjaro?
Yes, some insurance companies may cover your prescription for Mounjaro, but this will vary based on your insurance plan and drug benefits. Your insurance company may cover Mounjaro for type 2 diabetes, but may not cover Mounjaro for weight loss. To find out if your drug plan will pay for Mounjaro, contact your drug benefit company and ask if Mounjaro is on their formulary, and which conditions it covers.
Mounjaro $25 Coupon
Eli Lilly, the manufacturer of Mounjaro, offers a $25 Savings Card that can lower the cost to $25 for up to a 3-month supply, if you have commercial prescription insurance and a documented diagnosis of type 2 diabetes. Patients covered under government insurance, such as Medicare or Medicaid, do not qualify for the $25 savings card. To check If you're eligible for the savings program, click the link below.
See also "What is the Mounjaro Coupon or Savings Card?"
This is not all the information you need to know about Mounjaro (tirzepatide) for safe and effective use and does not take the place of your doctor’s directions. Review the full Mounjaro information and discuss this information and any questions you have with your doctor or other healthcare provider.
References
- Mounjaro Prescribing Information Accessed July 18, 2025 at https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/215866s031lbl.pdf
- Tirzepatide Once Weekly for the Treatment of Obesity Accessed July 18, 2025 at https://www.nejm.org/doi/full/10.1056/NEJMoa2206038
- Zepbound FDA Product Label Accessed July 18, 2025 https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/217806s000lbl.pdf
- How May GIP Enhance the Therapeutic Efficacy of GLP-1? Accessed July 18, 2025 https://pubmed.ncbi.nlm.nih.gov/32396843/
Read next
Why am I not losing weight on Mounjaro?
It takes time, about 8 to 12 weeks to see a 6% to 8% weight loss in adults using Mounjaro. Other reasons include the need to follow a reduced calorie diet and exercise program, your dose may need to be increased, or side effects may affect your treatment. Continue reading
Ozempic Mounjaro Wegovy & Zepbound: Weight Loss Compared
Ozempic, Mounjaro, Wegovy and Zepbound can all lead to long-term weight loss, but only Wegovy and Zepbound are approved by the FDA for this use. In studies, Zepbound has led to a 21% weight loss in adults using the highest dose, while Wegovy has led to about a 15% weight loss.
Continue reading
Do Ozempic, Wegovy, Mounjaro & Zepbound cause hair loss?
There’s no evidence that hair loss is a direct side effect of Ozempic, Wegovy, Mounjaro or Zepbound. Hair loss is more likely due to the stress of rapid weight loss on your body, which can lead to temporary shedding of hair over several months, a condition known as telogen effluvium. Continue reading
See also:
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