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Does Mounjaro cause fatigue?

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Feb 12, 2025.

Official Answer by Drugs.com

Mounjaro (generic name: tirzepatide) does not usually cause fatigue, which can leave you feeling tired, weak and with low energy. However, fatigue can be a common side effect associated with type 2 diabetes. Talk to your doctor if your symptoms of fatigue continue or are severe.

Some people have complained of fatigue after using Mounjaro as seen in the Mounjaro User Reviews, but the manufacturer did not report this side effect.

Learn more: User Reviews for Mounjaro

Symptoms of type 2 diabetes include:

Mounjaro injection is approved as a once-weekly injectin to treat high blood sugar levels in adults with type 2 diabetes, used alongside diet and exercise. With type 2 diabetes, your body does not use your blood sugar properly leading to high levels in your circulation. High blood sugars can lead to health complications over time, such as nervous system, immune and heart conditions.

When was Mounjaro approved by the FDA?

Mounjaro (tirzepatide) injection was approved by the FDA in May 2022. It is used to improve blood sugar (glucose) control in adults with type 2 diabetes. You should use it with a diet and exercise plan as recommended by your doctor. 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.

What side effects should I expect with Mounjaro?

Stomach (gastrointestinal) side effects are the most common side effects reported in studies with Mounjaro. Higher doses may be associated with more frequent stomach side effects. Most side effects with Mounjaro usually go away in days to weeks after starting treatment.

Side effects reported in at least 5% of patients included:

Serious side effects include: pancreatitis (inflammation of the pancreas); hypoglycemia (low blood sugar) with use of other diabetes treatments; allergies which can be severe; sudden (acute) kidney injury; severe gastrointestinal (digestive tract) disease; diabetic retinopathy (eye disease) complications; sudden (acute) gallbladder disease.

The package insert also carries a Boxed Warning for thyroid C-cell tumors. Mounjaro causes thyroid C-cell tumors in rats, but this occurrence in human is not known.

Related: Mounjaro side effects (in more detail)

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.

Related questions

References
  • FDA Approves Novel, Dual-Targeted Treatment for Type 2 Diabetes. FDA. Accessed Oct 20, 202 at https://www.fda.gov/news-events/press-announcements/fda-approves-novel-dual-targeted-treatment-type-2-diabetes
  • Mounjaro (tirzepatide) prescribing information. Eli Lilly. Indianapolis, IN. Accessed Oct 18, 2022 at https://uspl.lilly.com/mounjaro/mounjaro.html#pi
  • Type 2 diabetes. Mayo Clinic. Drugs.com. Accessed Oct 18, 2022 at https://www.drugs.com/mcd/type-2-diabetes#symptoms
  • Mounjaro.com. Eli Lilly. Accessed Oct 11, 2022 at https://www.mounjaro.com/

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

How do Ozempic, Mounjaro, Wegovy, Zepbound compare for weight loss?

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

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