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Does Mounjaro work for weight loss?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Oct 11, 2022.

Official answer

by Drugs.com

Yes, Mounjaro (tirzepatide) has been shown to lead to weight loss when used to treat adults with type 2 diabetes, alongside diet and exercise. While not approved for weight loss, participants treated with Mounjaro in studies lost between 5.5 kg (12 lbs) to 11 kg (25 lbs) on average.

  • Mounjaro injection is approved to improve blood sugar (glucose) in adults with type 2 diabetes mellitus.
  • It is injected under the skin (subcutaneously) of your stomach (abdomen), thigh, or upper arm one time per week, at any time of the day.
  • You should use it with a diet and exercise plan as recommended by your healthcare provider.

It is not known if Mounjaro can be used in people who have had inflammation of the pancreas (pancreatitis). Mounjaro is not for use in people with type 1 diabetes. It is not known if it is safe or effective in children under 18 years of age.

How much weight can I lose? How quickly does it work?

In studies, with or without other diabetes medications, weight loss in adults reached 11.4 kg (25 lbs) over 52-week long studies. Higher doses of Mounjaro led to greater weight loss, but may also be associated with greater stomach side effects.

Mounjaro is used to lower blood glucose (sugar) levels in patients with type 2 diabetes. Mounjaro lowers fasting and postprandial glucose concentration, decreases food intake, and reduces body weight in patients with type 2 diabetes.

It is not approved to be used as a weight loss drug; however, losing just 5% to 7% of your body weight may improve your diabetes control.

Is Mounjaro FDA-approved for weight loss?

No, Mounjaro is not approved by the FDA specifically as a weight loss drug. If you are using it alongside diet and exercise to improve blood sugar (glucose) for type 2 diabetes mellitus, you may lose some weight, which can be beneficial.

  • Approval was based on 5 clinical trials with over 6,200 participants in the Phase 3 SURPASS program. Length of the studies ranged from 40 to 52 weeks and included active comparators of injectable semaglutide 1 mg, insulin glargine and insulin degludec.
  • Efficacy was evaluated for Mounjaro 5 mg, 10 mg and 15 mg used alone (monotherapy) or in combination with commonly prescribed diabetes medications, including metformin, SGLT2 inhibitors, sulfonylureas and insulin glargine.
  • Participants achieved average A1C reductions between 1.8% and 2.4%.
  • While not indicated for weight loss, participants treated with Mounjaro lost between 5.5 kg (12 lbs) to 11 kg (25 lbs) on average. Higher doses resulted in greater weight loss.
  • The change in weight with the comparator agents ranged from a mean gain of 1.8 kg (4 lb) to a mean weight loss of 5.9 kg (13 lb).

How does Mounjaro help with weight loss?

Mounjaro helps with weight loss by decreasing food intake and slowing down how fast food travels through your digestive tract (called gastric emptying). This may help you to feel fuller for a longer period of time and reduce how much food you eat. Studies show this action may occur in the brain.

  • Mounjaro is a single molecule that activates glucose-dependent insulinotropic polypeptide (GIP) receptors and glucagon-like peptide-1 (GLP-1) receptors. GIP and GLP-1 are both natural incretin hormones.
  • GIP has been shown to decrease how much you eat and increase your energy expenditure, which results in weight loss. When combined with a GLP-1 receptor agonist, this may result in greater positive effects on blood glucose and body weight.
  • Mounjaro also slows the movement of food from the stomach into the small intestine. As a result, you may feel full more quickly and for a longer period of time, so you eat less.

Losing weight can improve how you respond to the insulin that your body releases from your pancreas, which helps lower your blood sugar.

Does Mounjaro cause stomach side effects?

Stomach side effects, such as nausea, diarrhea, and decreased appetite, are the most common side effects reported in studies with Mounjaro.

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.

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 health care provider.

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