Mounjaro: see answers to 14 questions about weight loss medication

Mounjaro , the commercial name for tirzepatide, is expected to go on sale in the coming days. The expectation of its official sale in Brazil has been stirring up pharmacies and generating discussions in different spaces.

The injectable medication, originally developed to treat type 2 diabetes , has been gaining prominence for its effectiveness in weight loss.

Its action is innovative, as the same substance combines two hormonal mechanisms: it is a GLP-1 receptor agonist (similar to semaglutide, the active ingredient in Ozempic and Wegovy) and a GIP agonist. Despite much talk about the drug, there are still doubts about tirzepatide — especially in comparison with semaglutide. To clarify the main points on the subject, we spoke to experts.

Questions about Mounjaro answered by experts 1. Is tirzepatide (Mounjaro) more effective than semaglutide?

Yes . According to endocrinologist and member of the Brazilian Society of Endocrinology and Metabolism (SBEM), Carolina Janovsky, comparative studies indicate that tirzepatide is more effective for weight loss in obese people.

“On average, patients who used tirzepatide lost about 20% of their body weight, while those who used semaglutide lost about 13%,” comments Carolina.

2. Can tirzepatide (Mounjaro) be used even without diabetes?

Yes . Although approval in Brazil by the National Health Surveillance Agency (Anvisa) is restricted to glycemic control in adults with type 2 diabetes, Carolina highlights the approval of Zepbound in the United States. Zepbound is the commercial name for tirzepatide aimed at treating moderate to severe obstructive sleep apnea in adults with obesity.

3. Does tirzepatide (Mounjaro) cause side effects?

Yes . The most common side effects include nausea, diarrhea, constipation and, in some cases, vomiting. “These symptoms usually appear in the first few weeks of use and tend to decrease over time. Loss of appetite may also occur, which is related to its mechanism of action,” says Carolina.

4. Is tirzepatide (Mounjaro) approved for the general population?

No. According to the medicine's leaflet, provided by the Eli Lilly laboratory, the medicine is contraindicated for:

• pregnant women;
• lactating women;
• children and adolescents (approved use for adults only);
• people with pancreatitis;
• people with a personal or family history of medullary thyroid cancer;
• people with allergies to components of the formula.

“People with a rare genetic syndrome called MEN-2 should not use it,” adds Janovsky.

5. Can the use of tirzepatide (Mounjaro) alter the menstrual cycle?

Yes . Some women report changes in their menstrual flow or rhythm while taking the medication, explains Carolina. “This may be related to both weight loss and hormonal changes caused by the medication.”

According to Rosália Padovani, an endocrinologist and director of the Brazilian Society of Endocrinology and Metabolism – São Paulo Region (SBEM-SP), studies on the impacts of tirzepatide use are still limited. “It is essential that any change in the menstrual cycle be communicated to the doctor, so that the situation can be monitored appropriately,” advises Padovani.

6. Can tirzepatide (Mounjaro) interfere with sleep, mood, or mental health?

Yes . As with changes in menstruation, both Janovsky and Padovani mention reports of negative changes. These effects vary between individuals. “On the other hand, by improving sleep apnea , there may be an improvement in sleep and mood, leading to benefits in mental health,” says Carolina.

7. Is it necessary to follow a specific diet while taking tirzepatide (Mounjaro)?

No , but that doesn’t mean that anything goes. Even without a mandatory restrictive diet, it’s essential to maintain a healthy and balanced diet to enhance the effects and maintain the results. “Eating well is still essential,” says Janovsky.

8. Do I need to have tests before starting to use tirzepatide (Mounjaro)?

Yes . It is important to assess kidney and liver function, as well as cholesterol, blood glucose and blood pressure profiles. Women of childbearing age should take a pregnancy test before starting treatment.

9. Can losing weight with tirzepatide (Mounjaro) make the body saggy?

Yes . This occurs mainly when weight loss is rapid and without exercise. Dermatologist Gessica Ramos, a full member of the Brazilian Society of Dermatology (SBD), recommends monitoring by an endocrinologist and nutritionist, in addition to dermatological treatments to maintain skin quality and volume replacement, if necessary.

“Regarding skin firmness, I recommend that patients begin collagen biostimulation and skin quality improvement treatments right at the beginning of their Mounjaro treatment — and don’t wait until they reach their goal of total weight loss,” advises Gessica.

10. Can hair and nails also be affected?

Yes . Hair loss and weakening of the nails may occur in some cases. Gessica explains that although the medication does not directly interfere with the absorption of nutrients — as occurs after bariatric surgery — the reduced appetite may decrease the intake of certain foods, which leads to nutritional deficiencies.

“This is acute telogen effluvium . The body understands this as a ‘trauma’, a ‘stress’ and alters the hair cycle, causing acute hair loss. This is observed in any type of rapid weight loss, not only in cases of Mounjaro use”, explains the dermatologist. Drinking plenty of water, using moisturizers, maintaining a good intake of proteins and vitamins, and, if necessary, using supplements under medical supervision can help prevent these problems.

11. Is it possible to maintain the results after stopping use?

Yes . Some people are able to maintain some of their results, especially if they continue with healthy habits. However, there is a risk of weight regain.

When the medication is stopped, appetite tends to return and metabolism may slow down. This is especially true if there are no lifestyle changes. “It is essential that the patient maintains medical monitoring during and after the end of treatment, to ensure a healthy transition,” says Padovani.

12. Can tirzepatide (Mounjaro) be addictive?

No. The medication is not addictive like drugs that act directly on the brain. However, because it helps control appetite, there may be a perception of change after stopping.

“The dose starts low and is gradually increased, usually every four weeks, to allow the body to adapt and minimize side effects. This process is always done under medical supervision,” explains Janovsky.

“However, it is crucial that the use of any medication is done under the supervision of a healthcare professional,” adds Padovani.

13. Does tirzepatide (Mounjaro) replace exercise and healthy eating?

Absolutely not . Although it can be an ally in the weight loss process, it does not replace the role of a balanced diet and regular physical activity. “Adopting healthy habits, promoting lifestyle changes and re-educating your eating habits are essential for maintaining your weight and overall health,” says Padovani.

14. Is it safe to use tirzepatide for life?

It is not yet known . According to Carolina, the longest studies to date have followed patients for two to three years safely. “The tendency is that, like other chronic medications, treatment can be prolonged, as long as it is well tolerated and monitored by a doctor,” concludes the endocrinologist.

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