Zepbound Side Effects
Zepbound (tirzepatide) is a once weekly injection approved for weight management and for obstructive sleep apnea in adults with obesity. This page explains the side effects named in its FDA approved prescribing information, in plain language: the reactions reported most often, when they tend to happen, and the serious warnings on the label. It is education only, not medical advice.
The most common Zepbound side effects
Most of the reactions reported with Zepbound involve the stomach and digestion, because the medicine slows stomach emptying and reduces appetite. The reactions named as most common in the prescribing information are:
- Nausea. The most frequently reported reaction, especially in the first weeks and after increases.
- Diarrhea. Loose or frequent stools, reported most often while the dose is going up.
- Vomiting. Often connected to dose increases or to eating past the point of fullness.
- Constipation. Slower digestion can mean less frequent, harder stools.
- Stomach pain. Abdominal pain or discomfort, along with indigestion and reflux.
- Injection site reactions. Redness, itching or bruising where the pen was used, usually mild.
- Fatigue. Tiredness is listed among the common reactions, as are belching and hair loss.
Hair loss appears in the reactions reported in the Zepbound trials. Shedding during weight loss treatment is usually tied to the rapid weight loss itself, and our GLP-1 hair loss guide explains why that happens. Not everyone gets these effects, and the pattern varies a lot from person to person.
When side effects tend to happen
The stomach related reactions are reported most often during dose escalation, when the dose is stepped up every four weeks. The Zepbound dosage chart shows that climb, from the 2.5 mg starting dose up through the maintenance doses. The early low doses are there to let the body adjust. For many people, reactions that flare after an increase ease once the dose stays the same for a while. Side effects that are severe or not settling are a common reason a prescriber holds a dose for longer instead of stepping up on schedule.
Warnings in the Zepbound prescribing information
Boxed warning: thyroid C-cell tumors. The strongest warning on the label is about a possible risk of thyroid C-cell tumors. In animal studies, tirzepatide caused these tumors in rats. It is not known whether Zepbound causes them in people. The label says the medicine should not be used by people with a personal or family history of medullary thyroid carcinoma, or with a condition called multiple endocrine neoplasia syndrome type 2.
Pancreatitis. Inflammation of the pancreas has been reported with this class of medicine. The label describes severe stomach pain, sometimes spreading to the back, as the warning sign.
Gallbladder problems. Gallstones and gallbladder inflammation have been reported, and rapid weight loss itself raises gallstone risk. Pain in the upper right stomach area, fever, or yellowing of the skin or eyes are the signs the label points to.
Severe stomach problems. Because Zepbound slows stomach emptying, the label notes it has not been studied in people with severe gastroparesis and is generally not recommended for them.
Allergic reactions. Serious allergic reactions, including anaphylaxis and swelling of the face, lips or tongue, have been reported with tirzepatide medicines. The label also lists milder hypersensitivity reactions such as rash and eczema among reported events.
When to get medical care promptly
Some symptoms should never be waited out. Seek medical care promptly for severe or persistent stomach pain, signs of an allergic reaction such as swelling of the face, lips or tongue or trouble breathing, yellowing of the skin or eyes, or a lump or swelling in the neck, a hoarse voice, or trouble swallowing. Ongoing vomiting or diarrhea that stops you drinking enough fluid also deserves a prompt call, because dehydration can strain the kidneys.
Frequently asked questions
What are the most common side effects of Zepbound?
The reactions reported most often in the Zepbound prescribing information are nausea, diarrhea, vomiting, constipation and stomach pain, along with indigestion, injection site reactions, fatigue, belching, reflux and hair loss. Most of the list involves the stomach and digestion, which fits how the medicine works.
Do Zepbound side effects settle down over time?
For many people, yes. The stomach related reactions are reported most often during dose escalation, while the dose is stepped up every four weeks. As the body adjusts to a steady dose, they often become milder or less frequent, although not for everyone, and severe or ongoing symptoms should always be raised with the prescriber.
Does Zepbound cause hair loss?
Hair loss appears in the list of reactions reported in the Zepbound trials. Shedding during treatment is usually linked to the rapid weight loss itself rather than a direct effect of the medicine on hair, and it is typically temporary. Our GLP-1 hair loss guide explains the mechanism in more detail.
What is the boxed warning on the Zepbound label?
The boxed warning is about thyroid C-cell tumors. In studies, tirzepatide caused these tumors in rats. It is not known whether Zepbound causes them in people. Because of this, the label says the medicine should not be used by people with a personal or family history of medullary thyroid carcinoma, or with multiple endocrine neoplasia syndrome type 2.
When should someone taking Zepbound get medical care promptly?
The warnings on the label point to a few situations: severe or persistent stomach pain, which can be a sign of pancreatitis; signs of a serious allergic reaction such as swelling of the face, lips or tongue or trouble breathing; yellowing of the skin or eyes; and a lump or swelling in the neck, hoarseness or trouble swallowing.