Mounjaro weight loss: does it work?

Mounjaro is a glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist. It is FDA-approved (U.S. Food and Drug Administration) as an adjunct to diet and exercise to improve glycemic control in patients with type 2 diabetes mellitus. Mounjaro has not been studied in clinical trials with patients that have a history of pancreatitis.

What is Mounjaro (tirzepatide)?

Mounjaro (tirzepatide) is an injectable diabetes drug manufactured by Eli Lilly and Company. It is a new medication used along with diet and exercise to reduce blood sugar levels in adults with type 2 diabetes mellitus. Mounjaro is not indicated to treat type 1 diabetes mellitus or as a weight loss drug for the treatment of obesity.

How does Mounjaro work?

Mounjaro is a glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptor agonist. GIP and GLP-1 are hormones called incretins that are involved in managing your blood glucose levels. Mounjaro is the first medication in its class that stimulates both GLP-1 and GIP receptors. This leads to increased insulin secretion by your pancreas and increased sensitivity to the released insulin. It also blocks your liver from producing sugar. This combined effect helps to reduce your blood sugar levels.

Can I take Mounjaro for weight loss?

Mounjaro is not approved as yet for weight loss by the FDA. However, Mounjaro does cause weight loss when used with diet and exercise to treat adults with type 2 diabetes.

Is Mounjaro approved for weight loss?

Mounjaro is not approved by the FDA as a weight loss drug but you may lose some weight if you use it in combination with diet and exercise to improve blood sugar for type 2 diabetes mellitus.

How does Mounjaro work for weight loss?

Mounjaro helps to decrease food intake and slow gastric emptying. This is how quickly food passes through your digestive tract. This helps you to feel fuller for longer and reduces your appetite. Studies show this action may occur in the brain.

Mounjaro stimulates glucose-dependent insulinotropic polypeptide (GIP) receptors and glucagon-like peptide-1 receptors. GIP decreases how much food you eat and increases how much energy you use resulting in weight loss. This may give better results when used with a GLP-1 receptor agonist. Weight loss improves how your body responds to insulin released from your pancreas, helping to further lower your blood sugar.

What is the best way to take Mounjaro to lose weight?

Mounjaro is injected under the skin once weekly. You may inject Mounjaro into your abdomen, thigh, or upper arm. Your starting dose is 2.5 mg, increased every 4 weeks by 2.5 mg to a maximum of 15 mg once weekly.

How much weight can I lose on Mounjaro?

Adults using Mounjaro lost 25 lbs over a 52-week period when used with or without other diabetes medications. Higher doses led to increased weight loss, but also caused an increase in gastrointestinal side effects. Mounjaro is not however approved as a weight loss drug at this time.

What are the alternative weight loss medications to Mounjaro?

Alternative glucose-lowering medications for body weight management include Wegovy, Rybelsus, Compounded Semaglutide injection, and Ozempic, all of which contain semaglutide. These medications are long-acting versions of older GLP-1 medications such as Victoza, Saxenda, and Trulicity.

RELATED: Mounjaro vs TresibaMounjaro vs BydureonMounjaro vs WegovyMounjaro vs TrulicityMounjaro vs Ozempic

Which is better for weight loss Ozempic or Mounjaro?

Mounjaro and Ozempic are both indicated along with diet and exercise to decrease high blood sugar in adults with type 2 diabetes. They are both given as once-weekly subcutaneous injections.

In clinical trials comparing Mounjaro to other diabetes treatments, patients taking the highest recommended dose of Mounjaro lowered their HbA1c levels by 0.5% more than Ozempic.

Patients taking Mounjaro also lost more weight than those taking other medications. They also had an average weight loss of 12 pounds more than patients taking Ozempic, 29 pounds more than those on Tresiba (insulin degludec), and 27 pounds more than Toujeo (insulin glargine) patients.

However, the manufacturer of Oxempic reported fewer digestive side effects and a higher overall tolerance when compared to Mounjaro.

There is currently no generic alternative available for either medication. Mounjaro has an average cost of almost $1200 for 1 carton of 2.5mg/0.5ml pens while Ozempic costs approximately $1000 for #1 prefilled pen of 2mg/1.5ml.

How long does it take Mounjaro to start working?

Mounjaro will start working after the first dose but can take up to several months until you see its full benefit. This is usually because your doctor will titrate your dose every 4 weeks until they find the right dose for you.

What is the cost of Mounjaro?

Mounjaro costs without insurance will vary depending on how much you buy and the retailer you buy it from. As a guide, Mounjaro will typically cost around $975 for four weeks of treatment.

Compounded Tirzepatide is available through NiceRx. It is the compounded version of Mounjaro.

Understanding your dosage

Mounjaro is available in single-dose prefilled pens in strengths ranging from 2.5mg/0.5ml to 15mg/0.5ml single-dose prefilled pens.

To understand your dosage read the full prescribing information, instructions for use, and medication guide that comes with Mounjaro. Use Mounjaro exactly as your doctor prescribes it to you. Don’t change your dose or stop taking Mounjaro without discussing it with them.

Mounjaro is injected subcutaneously (under the skin) into your stomach, thigh, or upper arm once a week at any time of the day. It can be taken with or without food. You can change the day of the week you administer Mounjaro if the time between the doses is at least 72 hours (3 days). Rotate the injection site each week.

If you miss a dose of Mounjaro, take the missed dose immediately if it is within the first 4 days after missing the dose. If it has been more than 4 days, skip the missed dose and take your next dose on its scheduled day. Do NOT take 2 doses of Mounjaro within 3 days of each other.

You can inject insulin and Mounjaro in the same area of your body, just not right next to each other. Do not mix the medications together in the same injection.

Store Mounjaro in its original carton in the refrigerator between 36⁰F to 46⁰F (2⁰C to 8⁰C). Each single-dose pen can be stored up to 86⁰F (30⁰C) for 21 days. Do not freeze Mounjaro or use it if it has been frozen.

How do injection pens work?

Pens are preloaded with insulin. To use, twist on a new needle, dial your recommended dose, inject your insulin, and discard the used needle into a sharps container.

Potential side effects

The most common side effects of Mounjaro compared to placebo include:

  • Low blood sugar
  • Nausea
  • Diarrhea
  • Injection site reactions
  • Decreased appetite
  • Vomiting
  • Constipation
  • Indigestion
  • Abdominal pain

Mounjaro can cause serious side effects including:

  • Increased risk of thyroid cancer including thyroid c-cell tumors
  • Pancreatitis
  • Acute kidney injury
  • Diabetic retinopathy complications
  • Acute gallbladder disease

Contact your healthcare provider for medical advice about your medical condition or any side effects you experience while taking Mounjaro. You can report your side effects to the FDA at 1-800-FDA-1088 or

RELATED: Mounjaro side effects and how to avoid them

Medically reviewed

A medical professional has reviewed this article.

Jamie Winn, PharmD
Jamie Winn, PharmD

Jamie Winn, PharmD

Medical Writer & Reviewer

Jamie Winn, PharmD

Medical Writer & Reviewer

Dr. Jamie Winn received his Doctor of Pharmacy in 2002 from the University of South Carolina College of Pharmacy, Columbia, SC. Jamie is a medical reviewer for NiceRx.

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The content on this website is intended for information purposes only. It does not constitute medical advice. The information on this website should not be relied upon and is not a substitute for professional medical advice. You should always speak to your doctor regarding the risks and benefits of any treatment.