The most common tirzepatide side effects are stomach and gut symptoms: nausea, diarrhea, vomiting and constipation. In the SURMOUNT-1 trial, nausea affected 24.6% to 33.3% of adults on tirzepatide, compared with 9.5% on placebo. Most cases were mild to moderate and showed up around dose increases. Serious risks are rare but real, and this page lists every one from the label. Start with our tirzepatide guide if you are new to the drug.
Key takeaways
- The Zepbound label lists 12 common adverse reactions: nausea, diarrhea, vomiting, constipation, abdominal pain, dyspepsia, injection site reactions, fatigue, hypersensitivity reactions, burping, hair loss and acid reflux.
- In SURMOUNT-1, 4.3% to 7.1% of adults on tirzepatide stopped the drug because of side effects, compared with 2.6% on placebo.
- The boxed warning covers thyroid C-cell tumors, which were seen in rats. Whether this applies to humans is unknown.
- Muscle pain, joint pain, headache and dizziness are not on the label's list of common adverse reactions. This page explains why they still get reported.
- Compounded tirzepatide is not FDA approved, so its side effects have not been studied in the same way as the branded product.
Tirzepatide side effects by dose: the SURMOUNT-1 numbers
SURMOUNT-1 followed 2,539 adults with obesity or overweight, without diabetes, for 72 weeks. Its side-effect table is the best public source for how often each symptom happens. Gut symptoms were mostly mild to moderate, and most showed up during dose escalation.
| Adverse event | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Nausea | 9.5% | 24.6% | 33.3% | 31.0% |
| Diarrhea | 7.3% | 18.7% | 21.2% | 23.0% |
| Vomiting | 1.7% | 8.3% | 10.7% | 12.2% |
| Constipation | 5.8% | 16.8% | 17.1% | 11.7% |
| Stopped the drug because of side effects | 2.6% | 4.3% | 7.1% | 6.2% |
Source: SURMOUNT-1, Jastreboff et al., NEJM 2022 (PubMed 35658024).
Two things stand out. Nausea did not keep climbing with dose: the 10 mg group had slightly more nausea than the 15 mg group. And most people who had side effects kept taking the drug.
The full list of common tirzepatide side effects on the label
The Zepbound prescribing information lists the adverse reactions that happened in at least 5% of trial participants and more often than with placebo. That list is the official answer to "what are the side effects of tirzepatide."
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Try the BMI Calculator →| Label adverse reaction | Plain English | Usually starts |
|---|---|---|
| Nausea | Queasy stomach | First doses and each dose increase |
| Diarrhea | Loose stools | First doses and each dose increase |
| Vomiting | Throwing up | First doses and each dose increase |
| Constipation | Hard or infrequent stools | Any time, often after a dose increase |
| Abdominal pain | Belly pain or cramping | Any time |
| Dyspepsia | Indigestion | Any time |
| Injection site reactions | Redness, itching or a bump at the shot site | Within hours of a shot |
| Fatigue | Tiredness or low energy | First weeks |
| Hypersensitivity reactions | Rash, hives, itching or swelling | Any time |
| Eructation | Burping | Any time |
| Hair loss | Shedding more hair than usual | Later, during rapid weight loss |
| Gastroesophageal reflux disease | Heartburn and acid reflux | Any time |
Source: Zepbound prescribing information, Adverse Reactions section (DailyMed).
The "usually starts" column reflects the trial pattern the label describes, where most gut symptoms appeared during dose escalation. The label gives no day-by-day timeline.
Why does tirzepatide cause diarrhea, nausea and constipation?
Tirzepatide activates two gut-hormone receptors, GLP-1 and GIP. Those signals do three things that matter for side effects. They slow how fast your stomach empties, so food sits longer and you feel full sooner. They act on appetite centers in the brain, so you eat less. And they change how the gut moves. A slower stomach explains nausea, bloating, burping and reflux. Changes in gut movement and lower food and fluid intake explain both diarrhea and constipation. That is why the same drug can cause opposite bowel problems in different people.
The label states that tirzepatide delays gastric emptying, and that the effect is greatest after the first dose and lessens over time. That matches the SURMOUNT-1 pattern.
Serious tirzepatide side effects: the boxed warning and every precaution
Serious side effects are uncommon, but the label gives each one a warning section. The table below lists all of them with the sign to watch for. Every row is a "call your prescriber now" or "seek urgent care" item.
| Label warning | What it means | Sign to watch for |
|---|---|---|
| Thyroid C-cell tumors (boxed warning) | Seen in rats; unknown whether it happens in humans. Do not use with a personal or family history of medullary thyroid carcinoma or MEN 2. | Lump in the neck, trouble swallowing, hoarseness, shortness of breath |
| Severe gastrointestinal disease | Not studied in people with severe gut disease, including severe gastroparesis | Gut symptoms that are severe or do not settle |
| Acute pancreatitis | Inflamed pancreas; stop the drug if suspected | Severe belly pain that may spread to the back, with or without vomiting |
| Acute gallbladder disease | Gallstones or gallbladder inflammation | Pain in the upper right belly, fever, yellow skin or eyes, clay-colored stool |
| Acute kidney injury | Dehydration from vomiting or diarrhea can hurt the kidneys | Very little urine, dizziness, confusion, or gut symptoms you cannot keep fluids through |
| Hypoglycemia | Low blood sugar, mainly when combined with insulin or a sulfonylurea | Shakiness, sweating, confusion, fast heartbeat, hunger |
| Hypersensitivity reactions | Allergic reactions, including serious ones | Swelling of the face, lips or throat, hives, trouble breathing |
| Diabetic retinopathy complications in patients with type 2 diabetes (Mounjaro, and added to the Zepbound label 08/2026) | Eye disease can worsen with fast blood-sugar improvement in people who already have it | Vision changes |
| Pulmonary aspiration under anesthesia | Food left in the stomach during deep sedation | Tell your surgical team you take tirzepatide before any procedure |
| Never share a KwikPen between patients (Zepbound) | Sharing a pen can pass blood-borne infections, even with a new needle | Not a symptom to watch for. One pen, one person, always |
Source: Zepbound and Mounjaro prescribing information, Boxed Warning, Contraindications and Warnings and Precautions sections (DailyMed).
What to expect after the first dose of tirzepatide
The label schedule starts everyone at 2.5 mg once weekly for four weeks. That first dose is a starting dose, not a treatment dose, and it exists to let your gut adjust. After at least four weeks you may move up in 2.5 mg steps. Because tirzepatide has a half-life of about five days, each new dose builds up over roughly four weeks before it reaches a steady level. Side effects tend to follow that curve: strongest in the first one to two weeks after a change, then settling.
| Phase | Label dose | What usually happens |
|---|---|---|
| Weeks 1 to 4 | 2.5 mg weekly (starting dose) | Appetite drops; mild nausea, burping or loose stools in some people |
| Weeks 5 to 8 | 5 mg weekly (first maintenance dose) | Gut symptoms may return for a week or two after the step up |
| Every later step | Up in 2.5 mg steps after at least 4 weeks, to a maximum of 15 mg | Same pattern; SURMOUNT-1 saw most events during escalation |
Source: Zepbound prescribing information, Dosage and Administration and Clinical Pharmacology sections; SURMOUNT-1 (PubMed 35658024).
Only your prescriber decides when you move up, stay, or go back down. Never change the dose on your own. Our tirzepatide dosage chart shows the full label schedule, and our first week on tirzepatide page walks through the early days.
How to take tirzepatide to keep side effects down
Tirzepatide is injected under the skin once a week, in the belly, thigh or upper arm, at any time of day, with or without food. Rotate the site each week. Beyond the injection itself, a few habits help: eat smaller meals, stop when you feel full, go easy on fatty and fried food, sip water through the day, and avoid lying down right after eating. Tell your prescriber if symptoms get in the way of eating or drinking.
Tirzepatide side effects muscle pain, body aches and joint pain
Muscle pain, body aches and joint pain are not on the Zepbound or Mounjaro list of common adverse reactions, and SURMOUNT-1 did not report them as a common event. That does not mean they never happen. Three explanations are plausible. Rapid weight loss can cost you some muscle along with fat, and losing muscle while staying active can feel like soreness. Eating far less can mean far less protein, which slows muscle repair. And dehydration from nausea, vomiting or simply forgetting to drink can cause cramps and aches. These are possibilities, not label facts. Sudden, severe muscle pain, dark urine, or pain with fever or a swollen joint needs a same-day call to your prescriber.
Tirzepatide headache, dizziness, dry mouth and fatigue
Headache, dizziness and dry mouth are not listed among the common adverse reactions on either label. When they show up, the usual suspects are the same: drinking less, eating less, and, for people also on insulin or a sulfonylurea, low blood sugar. Dizziness when you stand up is a classic sign of dehydration. The label's acute kidney injury warning is the reason to take this seriously. If you are dizzy and cannot keep fluids down, or you are passing very little urine, contact your prescriber that day. Fatigue, by contrast, is on the label's common list. Eating far less, poor sleep, and dehydration all feed it, and it is most common in the early weeks.
Tirzepatide rash and injection site reactions
Both hypersensitivity reactions and injection site reactions are on the label's common list. A small red, itchy bump at the shot site that fades within a day or two is typical. A spreading rash, hives, swelling of the face, lips or tongue, or trouble breathing is a hypersensitivity reaction. Stop the drug and get emergency care for those. Tirzepatide is contraindicated if you have had a serious allergic reaction to it before.
Tirzepatide side effects anxiety and mood
Anxiety is not a listed common adverse reaction. Earlier Zepbound labels carried a warning to monitor for depression and suicidal thoughts. FDA removed that warning in the February 2026 label revision after reviewing the evidence. Mood changes are still worth reporting to your prescriber, and if you have thoughts of harming yourself, call or text the 988 Suicide and Crisis Lifeline. For a fuller discussion see our page on tirzepatide and anxiety.
Tirzepatide side effects in females
The label does not publish a separate adverse-reaction table for women and men, so there is no verified "female side effects" list. Two label facts are sex-relevant. First, tirzepatide may cause fetal harm based on animal studies, and the Zepbound label says to stop the drug when pregnancy is recognized, because weight loss offers no benefit in pregnancy. Second, tirzepatide slows stomach emptying and can reduce absorption of birth control pills. The label tells people on oral hormonal contraceptives to switch to a non-oral method, or add a barrier method, for four weeks after starting and for four weeks after each dose increase. Hair loss, which is on the common list, is often what people mean when they search for female side effects. It is tied to rapid weight loss and is not described on the label as permanent.
Tirzepatide long term side effects
The longest controlled data come from the SURMOUNT-1 three-year extension. Adults with obesity and prediabetes took tirzepatide or placebo for 176 weeks. Weight change was 22.9% on 15 mg versus 2.1% on placebo, and progression to type 2 diabetes fell by 94%. The published trials do not report a new class of side effect appearing late, but three years is the limit of what has been studied. The thyroid C-cell question remains open because the human relevance of the rat finding is unknown.
Compounded tirzepatide side effects
Compounded tirzepatide is made by state-licensed 503A compounding pharmacies. It is not FDA approved and it is not interchangeable with Zepbound or Mounjaro. No SURMOUNT-style trial has been run on compounded products, so the numbers on this page come from the branded drug. The active ingredient is the same molecule, so the same warnings apply, and any added ingredient or different concentration is set by the pharmacy label. A licensed provider decides whether a compounded medication is appropriate for you. FormBlends prescriptions are written by independent clinicians of Recess MD LLC; you can see current pricing or start an assessment.
When to call your prescriber and when to seek urgent care
Call your prescriber the same day for: vomiting or diarrhea lasting more than a day or two, not being able to keep fluids down, passing much less urine, dizziness that does not improve with fluids, a new lump in your neck, hoarseness, or a mood change. Seek urgent or emergency care for: severe belly pain that will not ease, especially if it spreads to the back; pain in the upper right belly with fever or yellowing; swelling of the face or throat or trouble breathing; confusion or fainting; or thoughts of self-harm.
Frequently Asked Questions
What are the most common side effects of tirzepatide?
Nausea, diarrhea, vomiting and constipation are the most common, according to the Zepbound label and SURMOUNT-1. The label also lists abdominal pain, indigestion, injection site reactions, fatigue, hypersensitivity reactions, burping, hair loss and acid reflux. Most gut symptoms were mild to moderate and clustered around dose increases.
Does tirzepatide cause muscle pain or body aches?
Muscle pain and body aches are not on the label's list of common adverse reactions. When they happen, rapid weight loss, low protein intake and dehydration are the plausible explanations. Severe or sudden muscle pain, or aches with fever or dark urine, should be reported to your prescriber the same day.
Can tirzepatide cause headaches?
Headache is not listed as a common adverse reaction on the Zepbound or Mounjaro label. Drinking and eating less, and low blood sugar in people who also take insulin or a sulfonylurea, are the likely reasons it gets reported. A headache with vomiting you cannot control, confusion or vision changes needs urgent care.
What are compounded tirzepatide side effects?
Compounded tirzepatide has not been studied in a trial like SURMOUNT-1, so there is no separate side-effect list. It contains the same active molecule, so the same label warnings apply. It is not FDA approved and is not interchangeable with Zepbound or Mounjaro.
What are tirzepatide long term side effects?
The longest controlled data run 176 weeks, from the SURMOUNT-1 extension. Those trials did not report a new type of side effect appearing late. Beyond three years, no controlled data exist, and the human relevance of the rat thyroid tumor finding is still unknown.
Are tirzepatide side effects different in females?
The label does not break adverse reactions down by sex. The sex-specific label facts are the pregnancy warning, which says to stop Zepbound when pregnancy is recognized, and the oral contraceptive interaction, which calls for a non-oral or barrier method for four weeks after starting and after each dose increase.
Sources
- Zepbound (tirzepatide) prescribing information, DailyMed, Eli Lilly, revised 08/2026.
- Mounjaro (tirzepatide) prescribing information, DailyMed, Eli Lilly, revised 08/2026.
- Tirzepatide Once Weekly for the Treatment of Obesity (SURMOUNT-1), Jastreboff et al., New England Journal of Medicine, 2022.
- Tirzepatide for Obesity Treatment and Diabetes Prevention (SURMOUNT-1 three-year extension), Jastreboff et al., New England Journal of Medicine, 2025.
- FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss, U.S. Food and Drug Administration.
Next steps
For single symptoms, read our pages on tirzepatide nausea and tirzepatide constipation. Browse the tirzepatide hub for every other tirzepatide question. Talk to a licensed clinician before starting, stopping or changing any dose. Compounded tirzepatide is not FDA approved and is not interchangeable with Zepbound or Mounjaro; a licensed provider decides whether it is appropriate for you.
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