Tirzepatide Side Effects: What's Common, What's Serious
How often each tirzepatide side effect happens by dose, what helps, and the warning signs that need medical care.
By
NativeMed
Medically reviewed by
Dr. James Teet, DO
Published
· Last reviewed
Key Takeaways
The most common tirzepatide side effects are nausea, diarrhea, constipation and vomiting. They're usually mild to moderate and ease over time.
Side effects are most likely after starting or increasing the dose, which is why the dose goes up slowly.
Only about 5% to 7% of people in the trials stopped because of side effects, compared with 3.4% on placebo.
Get emergency care for severe stomach pain that spreads to your back, or for trouble breathing or swelling of the face, lips or tongue.
Tirzepatide can make birth control pills less effective after starting and after each dose increase.
The most common side effects of tirzepatide are digestive: nausea, diarrhea, vomiting and constipation. They are usually mild to moderate, happen most often when you start or increase your dose, and tend to ease over time. Serious side effects are rare, but you should know the warning signs, including severe stomach pain, signs of an allergic reaction, and a lump or swelling in the neck.
This guide uses the side-effect data from the FDA-approved prescribing information for Zepbound (tirzepatide injection). It covers how often each side effect happens, what helps, and when to get medical care.
Important: this article is general information, not medical advice. Contact your provider about any side effect that worries you.
Common side effects of tirzepatide
In the Zepbound weight-loss trials, these side effects were reported by at least 2% of people taking tirzepatide, and more often than with placebo:
How often common side effects happened in the Zepbound weight-loss trials
Side effect | 5 mg | 10 mg | 15 mg | Placebo |
|---|---|---|---|---|
Nausea | 25% | 29% | 28% | 8% |
Diarrhea | 19% | 21% | 23% | 8% |
Constipation | 17% | 14% | 11% | 5% |
Vomiting | 8% | 11% | 13% | 2% |
Abdominal pain | 9% | 9% | 10% | 5% |
Indigestion | 9% | 9% | 10% | 4% |
Injection-site reactions | 6% | 8% | 8% | 2% |
Fatigue | 5% | 6% | 7% | 3% |
Allergic-type reactions (mostly rash or itching) | 5% | 5% | 5% | 3% |
Burping | 4% | 5% | 5% | 1% |
Hair loss | 5% | 4% | 5% | 1% |
Acid reflux (GERD) | 4% | 4% | 5% | 2% |
Dizziness | 4% | 5% | 4% | 2% |
Two things stand out. First, most people on tirzepatide did not have any single side effect: even nausea, the most common, affected fewer than 1 in 3. Second, side effects led only a small share of people to stop: about 5% to 7% across the three doses, compared with 3.4% on placebo.
These figures come from trials of the FDA-approved branded medication. Compounded tirzepatide has not been studied in the same way, and individual experiences vary.
Why side effects happen and when they ease
Tirzepatide slows how quickly food leaves your stomach and reduces appetite. That's part of how it works, and it's also why the stomach is where most side effects show up. They are most likely in the days after you start or move up a dose, which is why the dose is raised slowly, after at least 4 weeks at each step. For most people, they become milder as the body adjusts.
How to manage common side effects
Nausea: eat smaller meals, stop when you feel full, and go easy on fatty, fried or very sweet foods. Eating slowly helps.
Diarrhea or vomiting: drink plenty of fluids. Losing fluids can strain your kidneys, so contact your provider if you can't keep fluids down.
Constipation: drink water, add fiber gradually, and stay active.
Reflux and burping: avoid lying down right after eating and limit large late-night meals.
Injection-site reactions: rotate where you inject (stomach, thigh or upper arm).
Fatigue: make sure you're eating enough protein and drinking enough fluids, since eating much less can leave you tired.
If side effects are hard to manage, don't stop or change your dose on your own. Your provider may keep you at your current dose for longer before increasing. If you're sick, hold your next injection until you have recovered.
Does tirzepatide cause hair loss?
It can. In the trials, about 5% of people taking tirzepatide reported hair loss, compared with 1% on placebo. It was more common in women (7.1%) than in men (0.5%), and no one stopped treatment because of it. Hair shedding after fast weight loss is common with any method of losing weight, and it usually improves with time and good nutrition.
Serious side effects: warning signs
These are uncommon, but they need prompt attention:
Serious side effects of tirzepatide and what to do
Possible problem | Warning signs | What to do |
|---|---|---|
Pancreatitis | Severe stomach pain that doesn't go away, sometimes spreading to your back, with or without vomiting | Stop and get emergency care |
Gallbladder problems | Pain in the upper right stomach, fever, yellow skin or eyes, clay-colored stools | Contact your provider right away |
Serious allergic reaction | Trouble breathing, swelling of the face, lips or tongue, severe rash, fast heartbeat, fainting | Call 911 |
Kidney problems from fluid loss | Ongoing vomiting or diarrhea, very little urine, feeling faint | Contact your provider right away |
Low blood sugar (mainly with insulin or other diabetes medications) | Shakiness, sweating, confusion, fast heartbeat | Treat with fast-acting sugar and contact your provider |
Possible thyroid tumor | A lump or swelling in the neck, hoarseness, trouble swallowing, shortness of breath | Tell your provider right away |
Also tell your provider right away about any thoughts of harming yourself or unusual changes in mood.
The thyroid warning
Zepbound carries a boxed warning, the FDA's most prominent type of warning. In studies in rats, tirzepatide caused thyroid C-cell tumors. It is not known whether it causes these tumors, including medullary thyroid cancer, in people. Because of this, tirzepatide should not be used by anyone who has had medullary thyroid cancer, has a family member who has had it, or has MEN 2.
Before surgery or sedation
Because tirzepatide slows stomach emptying, tell every doctor or dentist that you take it before any procedure that involves anesthesia or deep sedation. Food remaining in the stomach can raise the risk of inhaling it into the lungs.
Birth control and pregnancy
Tirzepatide can make birth control pills less effective. If you use birth control pills, switch to a non-oral method or add a barrier method for 4 weeks after starting and for 4 weeks after each dose increase. Do not use tirzepatide during pregnancy or while breastfeeding, and stop at least 2 months before a planned pregnancy.
If you take too much
Extra medication most often causes mild stomach side effects. If nausea, vomiting or abdominal discomfort keeps getting worse, go to urgent care because this can be pancreatitis. Never double up on doses. If you believe you took more than prescribed, contact your healthcare provider promptly. You may also contact Poison Control at 1-800-222-1222. For severe or life-threatening symptoms, call 911 or seek emergency medical attention.
Side effects and compounded tirzepatide
Compounded tirzepatide is not FDA-approved and hasn't been studied in the trials above, so its side-effect rates aren't known in the same way. Measuring errors are a real risk with multi-dose vials: FDA has received reports of patients drawing 50 units instead of 5. Always check your vial's concentration and your prescribed dose, and see our tirzepatide dosage chart for how to convert mg to units.
Managing side effects with NativeMed
At NativeMed, a licensed U.S. provider reviews your health history before prescribing and adjusts your dose based on how you respond, including how well you tolerate it. Before treatment, you'll be asked to give your consent to treatment with a compounded medication. If side effects become a problem, contact your care team rather than changing your dose yourself.
Plans start from $183 a month, at the same price for any dose. See compounded tirzepatide plans.
Compounded medications are not approved by the FDA, and the FDA does not review them for safety, effectiveness or quality before they are dispensed. Individual results vary. Read the full Important Safety Information.
Frequently asked questions
What is the most common side effect of tirzepatide?
Nausea. In the Zepbound weight-loss trials, 25% to 29% of people reported nausea, depending on the dose, compared with 8% on placebo.
How long do tirzepatide side effects last?
Digestive side effects are most common in the days after starting or increasing a dose and usually ease as your body adjusts. If they don't improve, or are hard to manage, contact your provider.
What are the worst side effects of tirzepatide?
Serious side effects are uncommon but include pancreatitis, gallbladder problems, severe allergic reactions and kidney problems from fluid loss. Tirzepatide also has a boxed warning about thyroid C-cell tumors seen in rats.
Does tirzepatide make you tired?
It can. Fatigue was reported by 5% to 7% of people in the trials, compared with 3% on placebo. Eating enough protein and staying hydrated can help.
What should I do if I'm sick?
Hold your next injection until you have recovered.
Can I switch between semaglutide and tirzepatide?
Yes, but do not convert the dose yourself. You will need a new prescription, and the two medications should not overlap. The mg numbers are not comparable between them.
Medically reviewed by
Dr. James Teet, DO
Board-Certified Family Medicine Physician