Tirzepatide side effects, warnings, and what to know

Tirzepatide is the active ingredient in 2 prescription medications. Mounjaro for controlling blood sugar levels in people with type 2 diabetes mellitus. And Zepbound for helping people with obesity and overweight with weight loss and weight management. It’s also available as compounded tirzepatide.

If your provider recommends any form of tirzepatide for you, you want to know what tirzepatide side effects are. You also want to know about its warnings, contraindications, and potential drug interactions. 

In this article, we cover it all, so you can quickly recognize potential problems and help make your treatment safer and outcome more effective.

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What is tirzepatide?

Tirzepatide is the active ingredient in the brand-name prescription medications Zepbound and Moujaro, and compounded tirzepatide, available from compounding pharmacies.

Zepbound is made by Eli Lilly and approved by the U.S. Food and Drug Administration (FDA) for the treatment of obesity in adults with a body mass index (BMI) of 30 or higher. It’s also FDA-approved for overweight people with a BMI of 27 or higher who have at least 1 weight-related health condition, such as type 2 diabetes, high blood pressure, or high cholesterol, Either group must combine using Zepbound with diet and exercise.

Moujaro is also made by Eli Lilly and FDA-approved to help improve glycemic control when used with diet and exercise for people with type 2 diabetes. It should also be combined with diet and exercise.

Compounded tirzepatide isn’t FDA-approved. But when purchased from a reputable compounding pharmacy, the pharmacy will be FDA-regulated and use pharmaceutical-grade tirzepatide in the medication. 

Tirzepatide is a glucagon-like peptide-1 (GLP-1)/glucose-dependent insulinotropic polypeptide (GIP) dual agonist receptor medication. It mimics 2 natural hormones in the body GLP-1 and GIP. GLP-1 and GIP affect glucagon secretion, promote insulin secretion, and slow down how fast food leaves your stomach. By mimicking the natural hormones, medications with tirzepatide help improve blood sugar control and make you want to eat less and can lead to weight loss. 

People who took Zepbound in clinical trials lost up to 20.9% of their body weight in 72 weeks.

Those benefits can come at a cost though, in the form of side effects. 

The side effects of tirzepatide — what to know

Tirzepatide as the active ingredient in Zepbound and Mounjaro and compounded tirzepatide can cause side effects. The most common include nausea, diarrhea, decreased appetite, vomiting, constipation, indigestion, and stomach pain nausea. 

It’s during clinical trials — done as part of getting medications approved by the FDA — where issues with a medication and adverse effects are identified, which include:

• Common side effects, which usually affect more than 10 percent of participants in clinical trials.
• Serious side effects and adverse reactions that are more rare, affect fewer than 10% of trial participants, and may post more serious health consequences. 
• Warnings: These are alerts that tell you about possible dangers of using a medicine. They help you know what to watch out for and be careful about when taking the drug.
• Contraindications: These are reasons why someone shouldn’t use a certain medicine. It might be because of a health condition they have or because they’re taking another drug that doesn’t mix well with the studied medication.
• Drug interactions: These happen when 1 medicine affects the way another one works, makes one drug less effective, or increases the chances of side effects. 

Compounded medications, like compounded tirzepatide, aren’t tested in clinical trials, but their side effects are typically similar to those of brand-name drugs. This means they could have similar risks and should be used just as carefully. 

Because compounded medications are customized or made in small batches they may include ingredients not found in brand-name drugs. Those ingredients may have side effects of their own as well. 

What to know before you take tirzepatide

Before you begin taking Zepbound, Mounjaro, or compounded tirzepatide, it’s important to know about potential warnings, contraindications, possible drug interactions, and possible side effects.

Warnings for tirzepatide

An FDA boxed warning, once called a black box warning because it’s shown in a black box on a medication label, is the FDA’s strongest warning for a drug. It means the medication may have serious risks.

All GLP-1/GIP and GLP-1 receptor agonist medications, including Zepbound, have a boxed warning. This warning is because in animal studies on rats and mice, test animals developed thyroid tumors when given these medications. It’s not clear if humans develop tumors from taking Zepbound.

If you have a personal or family history of thyroid cancer, particularly medullary thyroid carcinoma (MTC, a type of thyroid cancer) or multiple endocrine neoplasia syndrome type 2 (MEN2), make sure to tell your healthcare provider. Your provider may choose to measure your serum calcitonin level. A high level may indicate MTC. Together, you can consider the risks and benefits of taking Zepbound.

Contraindications — who shouldn’t take tirzepatide

Zepbound, Mounjaro, and compounded tirzepatide shouldn’t be taken by people with:

• A personal or family have a history of MTC or (MEN 2)
• A history of a serious hypersensitivity reaction to tirzepatide or another ingredient in the medication because of the risk of serious reactions, like anaphylaxis and angioedema.

Always consult with a healthcare professional to determine if a medication is safe for you.

Possible drug interactions when taking tirzepatide

Tirzepatide can interact with other medications you take and change how tirzepatide or other medications work or increase possible side effects. 

When starting Zepbound, Mounjaro, or compounded tirzepatide, tell your provider if you’re taking insulin or an insulin secretagogue, such as sulfonylurea. Because tirzepatide reduces blood sugar levels, you may need to lower the dose of other diabetes medications to reduce the possibility of hypoglycemia (low blood sugar).

And because Zepbound, Mounjaro, and compounded tirzepatide can slow down how fast your stomach empties, they might affect how well other oral medications are absorbed. Be sure to give your provider a complete list of all medications you’re taking, including hormone-based oral birth control pills. 

Your provider may recommend you switch to a non-pill contraceptive method or add a barrier method, like a condom, for 4 weeks after starting Zepbound, Mounjaro, or compounded tirzepatide and for 4 weeks each time you increase your tirzepatide dose. 

Common tirzepatide side effects

The most common side effects of Zepbound including some that only happened to a small percentage of trial participants are shown in the table below.

Table 1: Most common potential side effects of Zepbound in clinical trials.

• Abdominal pain can include abdominal discomfort, abdominal pain, pain in the lower abdomen, pain in the upper abdomen, and abdominal tenderness
• Dyspepsia is pain or an uncomfortable feeling in the upper middle part of your stomach area and may include bloating, belching, and nausea
• Injection site reactions included bruising, injection site erythema (aka a red rash), injection site pruritus (aka itching), injection site pain, and injection site rash
• Fatigue include, asthenia (generalized weakness and lack of energy), lethargy (sleepiness), and/or malaise (feeling ill or unwell)
• Hypersensitivity reactions were primarily, but not exclusively, restricted to skin reactions or itching
• Hair loss occurred more often for women than men
• Abdominal distension is characterized by your stomach being outwardly swollen
• Hypotension encompasses a  decrease in blood pressure, low blood pressure, and orthostatic hypotension (a drop in blood pressure when standing)

Serious side effects of tirzepatide

Taking any medication can sometimes cause serious side effects, but these are rare. In clinical trials and post-marketing data, less than 10% of people who take Zepbound experienced serious side effects. But, when they did happen, they were sometimes dangerous. Serious side effects can lead to hospital stays, cause permanent harm or disability, lead to birth defects, or even be life-threatening.

Table 2: Serious side effects of Zepbound in clinical trials and in post-marketing data.

If you notice any of these side effects, contact your provider immediately. And consider reporting negative side effects — serious or common — to the FDA  by visiting MedWatch or calling 1-800-FDA-1088. 

Does tirzepatide have long-term side effects?

Zepbound and Mounjaro are relatively new drugs and there’s not a lot of data about long-term effects yet. Some potential long-term side effects include pancreatitis (which is inflammation of the pancreas) and kidney issues, though these are rare. 

The SURMOUNT-1 study looked at the safety and efficacy of tirzepatide for obesity over 176-weeks (3+ years) and found small numbers of negative longer-term effects. It also found some positive effects like a return to normal blood sugar levels in more of the participants who started the study with prediabetes and took tirzepatide compared to those on placebo. 

The study found that up to 81.8% of participants had at least one negative side effect. Four participants had pancreatitis, but none severe. More participants on tirzepatide than the placebo had cholecystitis and acute cholecystitis (inflammation of the gall bladder with or without gallstones) but the overall incidence was low. A small number of participants taking tirzepatide compared to the placebo also had cardiac disorders and renal (kidney) issues. Overall, the trial didn’t identify risks or side effects not seen in shorter studies. 

How to take tirzepatide

When taking Zepbound, Mounjaro, or compounded tirzepatide, you take it as a once-a-week self-injection under the skin usually in your belly, upper thigh, or back of your upper arm. If you don’t want to inject yourself, you can have someone else inject you, usually in the back of your upper arm.

Tirzepatide dosing 

Zepbound and Mounjaro come in pre-filled single-dose pens. Tirzepatide doses include 2.5, 5.0, 7.5, 10, 12.5, and 15 milligrams per 0.5 milliliters. Your provider will have you start at the smallest dose and increase your dose typically every 4 weeks until you reach your ideal maintenance dose. 

Your maintenance dose can be anywhere from 5.0 to 15 milligrams a week depending on how well your body tolerates it and how well it works for your needs.

Compounded tirzepatide will come in a vial and not a pen. You’ll use a separate needle to inject yourself. The dosages will be roughly the same as for Zepbound or Mounjaro. 

If you miss a dose of Zepbound, Mounjaro, or compounded tirzepatide, take it as soon as you remember, as long as it’s not too close to your next scheduled dose. This helps keep a steady level of the medicine in your body so it works best. If you miss a dose, here’s what to do:

• If it’s been 4 days or less (96 hours) since you missed it, take the missed dose.
• If it’s been more than 4 days, skip the missed dose and take your next dose at your usual time on your regular day.

How to store tirzepatide

Refrigerate Zepbound, Mounjaro at 36°F to 46°F (2°C to 8°C). Store compounded tirzepatide per the instructions from your pharmacy. If you need to, you can store each pen or vial at room temperature, but not at a temperature above  86°F (30°C), for up to 21 days. 

Once your medication reaches room temperature, don’t refrigerate it again. Instead, keep it at room temperature and throw it out if you don’t use it within 21 days. Never freeze tirzepatide. And don’t use it if it becomes frozen.

Also keep it in its original box or a cabinet or closet to protect it from light exposure.

How to reduce tirzepatide side effects 

The following tips may help reduce or minimize your side effects if you take Zepbound, Mounjaro, or compounded tirzepatide. You can also talk to your healthcare provider about ways to prevent or reduce the side effects. 

• Adjust your diet: To help reduce nausea, try eating smaller, more frequent meals instead of large ones. Avoiding spicy or fatty foods can also help. Sipping clear or ginger tea might soothe your stomach. If nausea persists, talk to your provider about over-the-counter (OTC) medications that can help.
• Stay hydrated: Nausea, vomiting, or diarrhea could lead to severe dehydration, which can cause acute kidney injury (AKI), where the kidneys can’t filter waste properly. Watch for signs of dehydration like being very thirsty, having a dry mouth, urinating less, feeling dizzy, headache, confusion, and rapid heartbeat or breathing.
• It’s important to drink enough fluids. If you get very dehydrated or notice signs of kidney problems, get medical help right away. Staying hydrated is extra important when dealing with diarrhea as a side effect. 
• Follow your provider’s directions: Always take tirzepatide exactly as prescribed by your provider. Adjustments to your dose should only be made under medical supervision.

Keep track of how you feel and note any side effects you experience. Sharing this information with your provider can help them provide the best advice. Remember, each person’s body reacts differently, so what works for one person might not work for another. Always prioritize your health and seek professional advice when needed.

Key takeaways 

• Tirzepatide is an active ingredient in prescription medications Zepbound, Mounjaro, and compounded tirzepatide. It works by mimicking 2 hormones in the body that help control blood sugar and how quickly food leaves your stomach. While successful, any of these medications can have side effects. 
• Many people who take tirzepatide may experience side effects like nausea, diarrhea, vomiting, or constipation. These symptoms can often decrease or go away as your body adjusts to the medication. They can also be addressed with dietary changes and over-the-counter medications.
• Although less common, there are serious side effects to be aware of, such as potential risks to kidney function or severe allergic reactions. Tirzepatide also comes with an FDA boxed warning about the risk of thyroid tumors.
• To minimize or manage potential side effects, it’s important to follow your healthcare provider’s advice, stay hydrated, and report any severe or persistent symptoms to your healthcare provider promptly. 

Learn more about tirzepatide from a licensed healthcare professional

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