The short answer
The most common tirzepatide (Zepbound) side effects are nausea, diarrhea, vomiting and constipation. On the FDA label, nausea affected 25% to 29% of people taking Zepbound, compared with 8% on placebo. Most stomach side effects happened while the dose was being raised, and they eased over time.
Serious side effects are much less common, and the label spells out the signs to watch for. Below are the label's numbers by dose and when side effects tend to show up. You'll also find simple ways to ease them and how our medical team keeps an eye on you. For pricing, see our tirzepatide cost guide.
Zepbound side effects by dose: the FDA label numbers
Nausea is the most common side effect at every dose, followed by diarrhea. This table comes from the Zepbound prescribing information (revised August 2026). It pools the label's two main weight-reduction trials, with 3,477 adults. It lists every side effect seen in at least 2% of people and more often than with placebo.
| Side effect | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Nausea | 8% | 25% | 29% | 28% |
| Diarrhea | 8% | 19% | 21% | 23% |
| Vomiting | 2% | 8% | 11% | 13% |
| Constipation | 5% | 17% | 14% | 11% |
| Stomach (abdominal) pain | 5% | 9% | 9% | 10% |
| Indigestion (dyspepsia) | 4% | 9% | 9% | 10% |
| Injection site reactions | 2% | 6% | 8% | 8% |
| Fatigue | 3% | 5% | 6% | 7% |
| Allergic-type (hypersensitivity) reactions | 3% | 5% | 5% | 5% |
| Burping (eructation) | 1% | 4% | 5% | 5% |
| Hair loss | 1% | 5% | 4% | 5% |
| Heartburn or reflux (GERD) | 2% | 4% | 4% | 5% |
| Gas (flatulence) | 2% | 3% | 3% | 4% |
| Bloating (abdominal distension) | 2% | 3% | 3% | 4% |
| Dizziness | 2% | 4% | 5% | 4% |
| Low blood pressure (hypotension) | 0% | 1% | 1% | 2% |
Two patterns stand out. Constipation was more common at 5 mg (17%) than at 15 mg (11%). Vomiting and diarrhea rose a little with each higher dose.
How common are stomach side effects overall?
About 56% of people on any Zepbound dose had at least one stomach or digestive side effect, according to the FDA label. On placebo, it was 30%. Most people kept going. Only 1.9% (5 mg), 3.3% (10 mg) and 4.3% (15 mg) stopped because of them, versus 0.5% on placebo.
In SURMOUNT-1, the 72-week trial of 2,539 adults published in the New England Journal of Medicine in 2022, most stomach side effects were mild to moderate. They happened mainly during dose escalation. Side effects of any kind led 4.3% to 7.1% of people on tirzepatide to stop, compared with 2.6% on placebo.
When side effects start, and how long they last
Side effects are most likely in the first weeks after you start and after each dose increase. The FDA label says most nausea, vomiting and diarrhea happened during dose escalation and decreased over time. It doesn't give a set number of days, because that varies from person to person.
That's why Zepbound starts low and climbs slowly:
| When | Weekly dose | Good to know |
|---|---|---|
| Weeks 1 to 4 | 2.5 mg | A starter dose so your body can adjust. The label doesn't use it as a maintenance dose |
| From week 5 | 5 mg | The first maintenance dose. Expect side effects to be most noticeable in the weeks after this step |
| At least 4 weeks apart, only if needed | 7.5 mg, 10 mg, 12.5 mg, 15 mg | Side effects can return for a while after each increase, then settle again |
If a step up doesn't agree with you, you don't have to push through it. The label allows a lower maintenance dose when a higher one isn't tolerated, and your provider can keep you on your current dose longer. Not everyone needs to reach 15 mg.
Simple ways to ease nausea, constipation and diarrhea
Smaller meals, stopping when you're full and steady fluids help most. These tips come from Eli Lilly's Zepbound patient guidance and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
For nausea
- Split three meals into four or more smaller ones.
- Stop eating as soon as you feel full.
- Go easy on fatty foods like butter and cheese.
- On rough days, try bland foods such as toast, crackers or rice.
For constipation
- Build up to 22 to 34 grams of fiber a day, the NIDDK range for adults, adding it a little at a time.
- Drink water and other fluids, which help fiber do its job.
- Tell us if it doesn't ease, and check with us before starting a laxative.
For diarrhea or vomiting
- Sip fluids through the day. Lilly notes that drinking fluids lowers the chance of dehydration.
- Call us if it doesn't go away. The FDA label links dehydration from ongoing vomiting or diarrhea to kidney problems.
Protein at every meal and regular strength training help you hold on to muscle while you eat less. A 2025 joint advisory from four obesity and nutrition societies recommends both during GLP-1 therapy. For weekly injection tips, see our aftercare guide.
Other side effects on the label
Beyond the stomach, the label lists hair loss, fatigue, injection site reactions, dizziness and allergic-type reactions. Here's what it reports for each.
- Hair loss. Reported in 7.1% of women and 0.5% of men on Zepbound, versus 1.3% and 0% on placebo. The label links it to weight reduction, and no one on Zepbound stopped treatment because of it.
- Fatigue. 5% to 7% on Zepbound, versus 3% on placebo.
- Injection site reactions. Redness, itching or discomfort where you inject, in 6% to 8%, versus 2% on placebo. Use a different spot each week.
- Dizziness and low blood pressure. Dizziness in 4% to 5%. Low blood pressure in 1.6%, versus 0.1% on placebo, and in 2.2% of people also taking blood pressure medicine.
- Heart rate. An average rise of 1 to 3 beats per minute.
- Allergic-type reactions. 5% on Zepbound, versus 3% on placebo. Serious reactions were rare, at 0.1%.
Serious warnings on the FDA label
Serious side effects are uncommon, and some happened at the same rate on placebo in the trials. The label still lists each one so you know the signs.
| Warning | What the label reports | Signs to watch for |
|---|---|---|
| Thyroid C-cell tumors (boxed warning) | Seen in rats. It isn't known whether tirzepatide causes them in people | A lump or swelling in the neck, hoarseness, trouble swallowing or shortness of breath |
| Severe stomach side effects | 1.7% to 3.1% across doses, versus 1% on placebo | Stomach problems that are severe or won't go away |
| Kidney injury from dehydration | Reported after approval, mostly in people dehydrated from stomach side effects | Vomiting or diarrhea that won't stop, or trouble keeping fluids down |
| Gallbladder disease | Gallstones in 1.1% vs 1% on placebo. Gallbladder inflammation in 0.7% vs 0.2% | Upper stomach pain, fever, yellowing skin or eyes, or clay-colored stools |
| Pancreatitis | 0.2% on Zepbound and 0.2% on placebo in the weight-reduction trials | Severe stomach pain that won't go away, sometimes spreading to the back, with or without vomiting |
| Serious allergic reaction | 0.1%, versus 0% on placebo | Swelling of the face, lips, tongue or throat, trouble breathing or swallowing, fainting or a very fast heartbeat |
| Low blood sugar | Mainly with insulin or a sulfonylurea. In the label's type 2 diabetes trial: 4.2% vs 1.3%, and 10.3% in people also taking a sulfonylurea | Shakiness, sweating, dizziness, confusion, hunger or a fast heartbeat |
| Diabetic eye disease | A watch point for people with type 2 diabetes | Any change in vision |
| Food in the lungs during anesthesia | Rare reports, because tirzepatide slows stomach emptying | Tell your surgeon and anesthesia team before any procedure |
The label's after-approval reports also include severe constipation and bowel blockage, so tell us about constipation that's severe or isn't improving. Any change in mood is worth raising at your check-in.
Who shouldn't take tirzepatide
The FDA label says not to use Zepbound if you or a family member has had medullary thyroid cancer, if you have MEN 2 (multiple endocrine neoplasia type 2), or if you've had a serious allergic reaction to tirzepatide. A few other situations call for a different plan:
| Situation | What the label says |
|---|---|
| Pregnancy | Stop Zepbound once pregnancy is recognized. Weight loss isn't recommended during pregnancy |
| Breastfeeding | There's no data on effects on a breastfed baby. Talk it through with your provider |
| Birth control pills | They may work less well. Switch to a non-oral method, or add a barrier method, for 4 weeks after starting and after each dose increase |
| Severe gastroparesis | Not recommended |
| Insulin or a sulfonylurea | The dose may need to come down to avoid low blood sugar |
| Children and teens | Safety and effectiveness haven't been established |
| Planned surgery or sedation | Tell every care team that you take it, well ahead of time |
Also mention any history of pancreatitis, gallbladder disease, kidney problems or diabetic eye disease at your consultation.
When to call us, and when to get care right away
Call us for side effects that don't ease, and get care right away for severe pain, yellowing skin or eyes, or trouble breathing.
| What you notice | What to do |
|---|---|
| Nausea, fullness, diarrhea, constipation or burping | Common, especially after a dose increase. Eat smaller meals, slow down and drink water. Tell us if it doesn't ease |
| Ongoing vomiting, or you can't keep fluids down | Call us. Dehydration can affect your kidneys |
| Severe stomach pain that won't go away, pain in your upper right belly, or yellowing skin or eyes | Seek care right away |
| A lump or swelling in your neck, trouble swallowing or hoarseness | Call us promptly |
| Swelling of your face or throat, or trouble breathing | Call 911 |
How our $100 membership keeps an eye on side effects
Your $100 monthly membership includes regular check-ins where your provider tracks your weight, side effects and labs, and raises your dose only when you're tolerating the current one. It covers:
- A medical consultation and health history review before you start
- Injection training at your first visit
- Dose changes in 2.5 mg steps, no sooner than every 4 weeks
- Regular check-ins on your weight, side effects and labs
- A maintenance plan once you reach your goal
Bloodwork is billed separately, and Zepbound is bought directly from Eli Lilly at its self-pay price. We prescribe brand-name Zepbound, the same product studied in the SURMOUNT trials. Care is overseen by our medical director, Dr. Andrei Gherghina, DO, a board-certified dermatologist. We're open every day, 8am to 8pm, at 4400 N. Federal Hwy, Suite 150, in Boca Raton. Learn more about the medical weight loss program or tirzepatide.
Questions we hear
Do side effects come back when my dose goes up?
Often, yes, for a while. The FDA label says most nausea, vomiting and diarrhea happened during dose escalation, which is why each step is at least 4 weeks apart.
How long does nausea from Zepbound last?
It usually eases as your body adjusts to each dose; the label says it decreased over time. If it's still bothering you after a few weeks on the same dose, tell us so we can adjust your plan.
Does tirzepatide cause hair loss?
Hair loss was reported in 7.1% of women and 0.5% of men on Zepbound in the label's weight-reduction trials. The label links it to weight reduction, and no one stopped treatment because of it.
Does Zepbound make you tired?
Fatigue was reported in 5% to 7% of people on Zepbound, versus 3% on placebo. Mention it at your check-in so your provider can look at your dose, eating and labs.
Are Zepbound and Mounjaro side effects the same?
They're the same active ingredient, tirzepatide, so the common side effects are similar. The numbers on this page come from the Zepbound label's weight-reduction trials. Mounjaro is approved for type 2 diabetes.
Should I stop Zepbound if I feel sick?
For ordinary nausea, don't stop on your own; call us and we'll adjust your plan. Stop and get care right away for severe stomach pain that won't go away, which the label says can be a sign of pancreatitis.
What if I miss a dose?
If it's within 4 days of your usual day, take it when you remember. If more than 4 days have passed, skip it and take the next dose on your usual day.
Questions about side effects or starting tirzepatide? Book a weight loss consultation or call (561) 621-1578. To compare medications, read semaglutide vs. tirzepatide.
Sources
- FDA prescribing information: Zepbound (tirzepatide), revised August 2026, via DailyMed
- Zepbound Medication Guide, via DailyMed
- FDA: Zepbound label (Drugs@FDA)
- Jastreboff et al., Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1), New England Journal of Medicine, 2022
- Eli Lilly: getting started with Zepbound
- NIDDK: eating, diet and nutrition for constipation
- Nutritional Priorities to Support GLP-1 Therapy for Obesity, joint advisory of the American College of Lifestyle Medicine, American Society for Nutrition, Obesity Medicine Association and The Obesity Society, 2025