Whether you suffer from Type 2 Diabetes or are in search of a safe and effective weight loss drug, you may be considering taking Mounjaro. This innovative blood sugar control medication is similar to other injectable GLP-1 agonist receptors like Ozempic, Wegovy, Saxenda, and Trulicity but distinguishes itself from the rest of the pack by also targeting GIP receptors in the body. It’s the first dual-agonist anti-diabetic drug to be approved by the FDA, and while it’s not yet officially approved for weight loss, the FDA is fast-tracking it for this purpose based on incredibly promising results from early clinical trials.

But what should you expect if you’re just starting on Mounjaro? Will your body adjust easily to the drug, or should you be prepared for some bumps along the way? While no one can predict exactly how your body will react to a new medication, it’s important to educate yourself about the potential side effects associated with Mounjaro so that you’ll be able to handle them effectively should they occur.

Be sure to disclose any medications you’re currently taking (including natural remedies and over-the-counter drugs), as well as provide a thorough medical history to your doctor before starting on Mounjaro. Your doctor will also be your best resource in helping you anticipate which side effects of Mounjaro you may be most likely to experience and offering an appropriate treatment plan if and when you do.

Below, we’ve taken a close look at Mounjaro’s side effects and provided answers to some frequently asked questions about them:

Key Takeaways

  • Mounjaro is a brand-name prescription drug that improves blood sugar control in adults with Type 2 Diabetes and is also associated with medically significant weight loss.
  • It’s classed as a dual-agonist drug because it is simultaneously a GLP-1 receptor agonist and a GIP receptor agonist.
  • Like all prescription medications, Mounjaro can cause side effects in some patients. While many Mounjaro side effects will resolve over time, others may not and may require medical treatment.
  • Common side effects of Mounjaro include gastrointestinal issues and injection site reactions. More serious side effects include severe digestive problems, gallbladder problems, pancreatitis, and an increased risk of thyroid tumors.
  • It’s important to educate yourself about the potential side effects of Mounjaro before you begin taking the drug. If you are experiencing severe or concerning side effects while taking Mounjaro, seek medical attention immediately.

What Is Mounjaro?

Mounjaro (tirzepatide) is a brand-name prescription drug manufactured by Eli Lilly. In 2022, it was FDA-approved for the treatment of Type 2 Diabetes in adults and has been associated with medically significant weight loss in clinical trials (though not yet officially approved for this purpose).

Mounjaro is injected once weekly under the skin of the thigh, abdomen, or upper arm and is most effective in combination with a healthy diet and regular exercise. It helps regulate blood sugar levels in the body by mimicking two different gut hormones known as glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP); it is classed as both a GLP-1 and GIP receptor agonist.

Mounjaro is the first dual-agonist drug to be approved for blood sugar control and works by stimulating insulin secretion in the pancreas, inhibiting glucagon production in the liver, and influencing appetite and eating decisions in the brain and other body systems. It also slows down gastric emptying (the rate at which food is emptied from the stomach).

Boxed Warning: Risk of Thyroid Cancer

A boxed warning (formerly a black box warning) is the highest level of warning that can be assigned to a medication by the FDA. Mounjaro, like many other GLP-1 receptor agonist drugs, has a boxed warning for the risk of Thyroid C-Cell tumor development and is contraindicated in patients with a personal or family history of Medullary Thyroid Carcinoma (MTC) or Multiple Endocrine Neoplasia Type 2 (MEN 2).

According to Mounjaro’s manufacturer, tirzepatide has been associated with an increased incidence of thyroid cancer in rodent trials. The exact implications of these findings for humans are not clear.

Common Mounjaro Side Effects

The most common side effects of Mounjaro (occurring in 5% or more of patients) include:

  • Nausea
  • Diarrhea
  • Decreased appetite
  • Vomiting
  • Constipation
  • Dyspepsia (indigestion)
  • Abdominal pain

Mild Side Effects of Mounjaro

Most of the common side effects listed above are also considered mild side effects of Mounjaro (unless they persist over time or become severe in nature). In most cases, they are most notable when first starting the drug or when dose escalations occur and tend to resolve over time as the body adjusts. Other mild side effects of Mounjaro can include:

  • Injection site reactions
  • Acid reflux
  • Gas and burping
  • Abdominal swelling

Serious Mounjaro Side Effects

More serious side effects of Mounjaro can include:

  • Serious allergic reactions
  • Severe hypoglycemia
  • Severe gastrointestinal issues
  • Vision problems (diabetic retinopathy)
  • Pancreatitis
  • Acute kidney injury
  • Acute gallbladder disease
  • The formation of thyroid tumors

How Long Does It Take Mounjaro Side Effects To Develop?

The period of time it takes for Mounjaro side effects to develop depends on a variety of factors, including your personal body chemistry, medical history, and the type of side effect in question.

Generally speaking, mild side effects tend to manifest rapidly and also resolve relatively quickly as the body adjusts to Mounjaro, while more serious side effects may take longer to manifest but often require medical attention and may not resolve as easily or effectively. While some patients may experience side effects within an hour or two of their first injection, others may take Mounjaro for months or years without noticing any side effects at all.

Early-Onset Side Effects

Mounjaro’s common and mild side effects (mainly gastrointestinal issues) tend to manifest early and respond well to conservative treatments such as hydration, rest, and fresh air. In many cases, they also respond effectively to over-the-counter medications, but it’s important to double-check with your healthcare provider first to mitigate the risk of any possible negative interactions. If early-onset side effects don’t improve or disappear within a few weeks after starting Mounjaro or increasing your weekly dose of the drug, seek medical advice.

Delayed-Onset Side Effects

Mounjaro’s delayed-onset side effects tend to be more serious than its early-onset side effects. Below, we’ve provided an overview of signs and symptoms never to ignore while on Mounjaro, no matter how long you’ve been taking the drug:

  • Serious allergic reactions – itching or hives; swelling of lips, tongue or face; difficulty breathing; dizziness or fainting; severe cramps or vomiting; anxiety
  • Severe hypoglycemia – Mounjaro is not associated with hypoglycemia on its own but can be when taken with insulin or other Type 2 Diabetes medications. Signs and symptoms of hypoglycemia include irritability or confusion, shakiness, sweating, dizziness, rapid pulse, and paleness; severe symptoms can include slurred speech, blurred vision, and loss of consciousness.
  • Severe gastrointestinal issues – gastrointestinal issues that cause intense pain or discomfort and interfere with your daily life on an ongoing basis
  • Vision problems – It is unknown if Mounjaro directly causes vision problems, but it has been shown to negatively impact some patients with a history of diabetic retinopathy. Watch for worsening vision, sudden vision loss, eye pain, blurred or patchy vision.
  • Pancreatitis – severe and worsening abdominal pain, fever and chills, rapid pulse, jaundice
  • Acute kidney injury – Can result from dehydration or lack of nutrition due to decreased appetite. Watch for weakness, confusion, swelling in legs, ankles, or feet, and infrequent urination.
  • Acute gallbladder disease – fever, nausea and vomiting, sweating, abdominal bulging, jaundice
  • The formation of thyroid tumors – persistent hoarseness or loss of voice, mass in the neck, difficulty swallowing

How Long Do Mounjaro Side Effects Last?

Mounjaro side effects can last anywhere from less than an hour to many weeks or months. If side effects are serious or persistent, your doctor may advise you to discontinue the use of Mounjaro and try another drug alternative in its place. Always seek medical advice before stopping the use of a prescription medication.

How To Deal With Mounjaro Side Effects?

The most appropriate management strategy for your Mounjaro side effects will depend on the nature of the side effects you are experiencing. In general, mild side effects can be managed with simple and readily available treatments such as:

  • Eating small portions
  • Maintaining a bland diet (avoiding fatty, spicy, and sugary foods)
  • Staying hydrated
  • Getting plenty of fresh air
  • Staying upright after meals
  • Increasing low-impact physical activity
  • Taking over-the-counter medications for symptom relief (pain relievers, antihistamines, anti-diarrheal medicines, etc.)

More serious side effects typically require a more comprehensive regimen of diagnostic tests and treatment options. In some cases, the discontinuation of Mounjaro may be necessary.

Mounjaro Side Effect FAQ

Does Mounjaro Cause Hair Loss?

While not a common side effect of Mounjaro, hair loss can be associated with taking the drug for some patients. Usually, hair loss is not directly caused by tirzepatide or any of the other ingredients in Mounjaro. Rather, it tends to be an indirect stress reaction resulting from rapid weight loss, dehydration, and/or a calorie-deficient diet while on the drug. If you experience hair loss while taking Mounjaro, speak with your health provider for treatment options.

Is Mounjaro Approved for Weight Loss?

Technically, Mounjaro is not approved for weight loss.  That being said, its active ingredient, tirzepatide, was recently approved by the FDA for weight loss and chronic weight management under the brand name Zepbound.  

Zepbound is indicated for use in adults who are obese (BMI over 30) or overweight (BMI over 27) with at least one weight-related medical condition.  Its composition and dosing schedule are the same as Mounjaro’s, but it’s still important to speak with your doctor about which medication may be the right option for your particular needs, weight loss goals, and circumstances. 

Can Mounjaro Cause Thyroid Cancer?

In rodent trials, tirzepatide (Mounjaro’s active ingredient) has been associated with increases in the incidence of thyroid C-cell tumors (adenomas and carcinomas). The increases impacted both sexes of rats equally and were dose-dependent and treatment-duration-dependent.

The relevance of rodent studies for humans remains unknown for thyroid cancer, but patients with a personal or family history of certain types of thyroid cancer are contraindicated from taking Mounjaro. Inform your doctor immediately if you are taking Mounjaro and feel a lump in your neck or experience ongoing hoarseness or difficulty swallowing.

Does Mounjaro Cause Kidney Problems?

Mounjaro does not directly cause kidney problems, but kidney problems may indirectly result from other side effects that the drug can cause. Gastrointestinal issues, such as vomiting and diarrhea, can cause dehydration, which, if severe enough, can lead to kidney damage. Acute kidney injuries have occasionally been reported in people taking GLP-1 receptor agonists. Be sure to stay hydrated at all times while taking Mounjaro and seek medical attention immediately if you experience symptoms of kidney problems such as frequent urination or swelling of the legs, ankles, or feet.

Does Mounjaro Affect the Gallbladder?

Though uncommon, it is possible for Mounjaro to cause gallbladder problems, such as an increased risk of gallstones. Eating a low-fat diet, losing weight, and engaging in regular physical activity (all of which are recommended while taking Mounjaro anyway) can decrease the risk of gallbladder issues and complications.

While on Mounjaro, pay attention to symptoms such as nausea, sweating, vomiting, and severe abdominal pain that don’t improve. If you suspect you may be experiencing gallbladder problems, seek medical attention immediately.

Does Mounjaro Cause Nausea?

Yes, Mounjaro can cause nausea for many patients. Gastrointestinal issues, including nausea and vomiting, are among the most common side effects associated with taking Mounjaro. To mitigate nausea from Mounjaro, try eating bland foods, getting outside in the fresh air, remaining upright after meals, and staying hydrated. You may also ask your doctor about the safety and potential effectiveness of over-the-counter nausea treatments. Fortunately, nausea tends to dissipate over time for most patients taking Mounjaro.

Can Mounjaro Cause Pancreatitis?

Pancreatitis (swelling of the pancreas) may be associated with Mounjaro in rare cases. Watch for persistent abdominal pain that may radiate to the back and may be accompanied by vomiting. If you experience symptoms of pancreatitis while taking Mounjaro, your doctor will likely replace your prescription with an alternate medication to avoid future flare-ups.

When Should I See a Doctor?

While you don’t need to rush to the doctor every time you experience some mild discomfort, seeking medical advice while on Mounjaro is essential for your health and safety. If you are experiencing side effects that concern you in any way, don’t hesitate to reach out to your doctor or healthcare provider for advice.

Here are some indicators that a conversation with your doctor may be in order:

  • Side effect symptoms are not decreasing or resolving over time
  • Side effects symptoms are impacting your daily life and ability to function
  • You are suddenly experiencing symptoms you’ve never experienced before
  • You suspect an underlying health condition may be contributing to side effect symptoms
  • Side effects are severe, and you believe immediate medical attention may be warranted

Your doctor may adjust your dose or dose schedule, recommend additional treatments to address side effect symptoms or decide to switch you to a different medication.


To conclude, Mounjaro (tirzepatide) is an injectable anti-diabetic medication that is unique among its competitors because it targets two different sets of incretin hormone receptors (GLP-1 and GIP receptors) instead of just one. It is associated with excellent blood sugar control outcomes as well as weight loss results (even though it is not yet officially approved for this purpose) and, along with other GLP-1 receptor agonists such as Ozempic, is currently in high demand.

If you’ve recently been prescribed Mounjaro or Ozempic or are considering speaking to your doctor about getting a prescription for either of these drugs, Bisonpharmacy.com can help. We ship high-quality Mounjaro and Ozempic to patients all across the U.S. and are always available to answer any questions you may have.

To order Mounjaro or Ozempic directly to your door at an affordable price, contact us at Bisonpharmacy.com today!

About the Author

Ida Edlweiss Gumpal is a licensed Pharmacist and medical writer. She took her internships at Mercury Drug Corporation, Inc., a Hospital internship at De Vera Medical Center, Inc., and a Manufacturing internship at Philmed Laboratories, Inc. She has plans on attending medical school with the goal of specializing in Neurosurgery or Cardiothoracic surgery.