Tirzepatide side effects, by dose, from the Zepbound label
Nausea hit 25–29% of Zepbound users vs 8% on placebo; most GI effects came during dose escalation. Every rate below is from the FDA label, with the source linked.
Key takeaways
- In the two 72-week weight trials, 56% of people on any Zepbound dose had a gastrointestinal side effect, versus 30% on placebo.
- Nausea: 25%, 29% and 28% at 5, 10 and 15 mg (8% placebo). Most nausea, vomiting and diarrhea happened during dose increases and faded.
- 4.8–6.7% stopped Zepbound because of side effects, compared with 3.4% on placebo.
- The label carries a boxed warning for thyroid C-cell tumors seen in rats; human relevance is unknown.
Tirzepatide is sold as Zepbound for weight management and sleep apnea, and as Mounjaro for type 2 diabetes. The side-effect figures below come from the Zepbound prescribing information (revised August 2026), which pools two placebo-controlled trials: 2,519 adults treated for up to 72 weeks. They describe the approved, manufactured product only.
Side effects by dose
| Side effect | Placebo | 5 mg | 10 mg | 15 mg |
|---|---|---|---|---|
| Nausea | 8% | 25% | 29% | 28% |
| Diarrhea | 8% | 19% | 21% | 23% |
| Constipation | 5% | 17% | 14% | 11% |
| Vomiting | 2% | 8% | 11% | 13% |
| Abdominal pain | 5% | 9% | 9% | 10% |
| Dyspepsia (indigestion) | 4% | 9% | 9% | 10% |
| Injection-site reactions | 2% | 6% | 8% | 8% |
| Fatigue | 3% | 5% | 6% | 7% |
| Hypersensitivity reactions | 3% | 5% | 5% | 5% |
| Burping (eructation) | 1% | 4% | 5% | 5% |
| Hair loss | 1% | 5% | 4% | 5% |
| Acid reflux (GERD) | 2% | 4% | 4% | 5% |
| Dizziness | 2% | 4% | 5% | 4% |
Source: Zepbound label, Table 1 (adverse reactions in at least 2% of patients and more often than placebo).
The pattern: worst during escalation
The label states that the majority of nausea, vomiting and diarrhea events occurred while the dose was being increased and decreased over time. That is the reason for the schedule: 2.5 mg weekly for four weeks, then 5 mg, with further 2.5 mg increases no sooner than every four weeks, to a maximum of 15 mg. Our tirzepatide dosage guide walks through it, and the Zepbound label schedule shows each step with the source.
Gastrointestinal effects overall affected 56% of people at every dose, against 30% on placebo. Stopping because of them was uncommon but dose-related: 1.9% at 5 mg, 3.3% at 10 mg and 4.3% at 15 mg, versus 0.5% on placebo.
Less common but serious
The label’s warnings section lists effects that are rarer but matter more:
- Thyroid C-cell tumors. Tirzepatide caused them in rats; it is unknown whether it does in people. Zepbound is contraindicated if you or a family member has had medullary thyroid carcinoma or you have MEN 2.
- Pancreatitis. Confirmed in 0.2% of Zepbound and 0.2% of placebo patients in the weight trials; stop the drug and seek care if severe abdominal pain develops.
- Gallbladder disease, kidney injury from dehydration (0.5% vs 0.2% placebo), low blood pressure (1.6% vs 0.1%), and serious allergic reactions.
- Aspiration under anesthesia. Because tirzepatide slows stomach emptying, tell the anesthetist before any procedure.
Hair loss and weight loss
Hair loss was linked to weight reduction rather than to the drug directly, and it was reported much more often in women (7.1%) than in men (0.5%). No Zepbound patient stopped because of it.
What these numbers do not cover
None of these rates applies to compounded tirzepatide, “research” vials or oral versions, because no trial has measured them. Those products can differ in dose, purity and sterility; see how to read a certificate of analysis and our tirzepatide price data for what vendors publish. For a side-by-side with semaglutide, see semaglutide side effects.
This page summarizes the FDA label for reference. It is not medical advice; report side effects to your prescriber or to FDA MedWatch.
What the evidence does not show
- Side-effect rates for compounded or research-grade tirzepatide: no trial has measured them.
- Rates for oral or sublingual tirzepatide products, which are not FDA-approved.
Frequently asked questions
What are the most common side effects of tirzepatide?
In the Zepbound weight-loss trials: nausea (25–29% depending on dose), diarrhea (19–23%), constipation (11–17%), vomiting (8–13%), dyspepsia and abdominal pain (9–10%), injection-site reactions (6–8%) and fatigue (5–7%).
How long do tirzepatide side effects last?
The label says most nausea, vomiting and diarrhea occurred during dose escalation and decreased over time. That is why the dose is raised in 2.5 mg steps no faster than every 4 weeks.
Does tirzepatide cause hair loss?
Hair loss was reported in 4–5% of Zepbound users vs 1% on placebo, was linked to weight reduction, and was far more common in women (7.1%) than men (0.5%). No one on Zepbound stopped treatment because of it.
Is the higher dose worse for side effects?
Vomiting and diarrhea rose with dose (vomiting 8%, 11%, 13% at 5, 10, 15 mg), and so did stopping for GI reasons (1.9%, 3.3%, 4.3%). Constipation was actually lowest at 15 mg (11%).
Does tirzepatide affect birth control pills?
Yes. The label advises people on oral hormonal contraceptives to switch to a non-oral method or add a barrier method for 4 weeks after starting and after each dose increase.
Sources
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