Quick answer: Tirzepatide (Mounjaro®, Zepbound®) has the same kind of side effects as semaglutide — mostly gastrointestinal — but the reported rates run somewhat lower. In Zepbound's trials: nausea ~25–29%, diarrhea ~19–23%, vomiting ~8–13%, and constipation ~11–17%, plus abdominal pain ~9–10% and fatigue ~5–7%. They are mild-to-moderate, dose-dependent, and worst during dose increases, then ease at a stable dose. The serious warnings (boxed thyroid-tumor warning, pancreatitis, gallbladder) are the same class effects as semaglutide. These rates are from trials of the FDA-approved branded medication; compounded tirzepatide was not studied in those trials and is not FDA-approved.
- Same GI-dominant profile as semaglutide: nausea ~25–29%, diarrhea ~19–23%, vomiting ~8–13%, constipation ~11–17% (from Zepbound trials).
- Side effects are mild-to-moderate and dose-dependent — worst during titration, then ease at a stable dose.
- Mounjaro and Zepbound are the same drug (tirzepatide made by Eli Lilly); the side-effect profile is identical.
- Same serious class warnings as semaglutide: boxed thyroid-tumor warning, pancreatitis risk, gallbladder disease.
- All reported rates come from trials of the FDA-approved branded drug — not from compounded tirzepatide products.
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Side effects at a glance
| Side effect | How common (Zepbound, 5–15 mg) | Notes |
|---|---|---|
| Nausea | ~25–29% | Most common; rates lower than semaglutide's ~44% by label, but not a head-to-head comparison |
| Diarrhea | ~19–23% | |
| Vomiting | ~8–13% | Higher at higher doses |
| Constipation | ~11–17% | |
| Abdominal pain | ~9–10% | |
| Fatigue | ~5–7% | Often from under-eating early on |
Side-effect rates are from the Zepbound FDA prescribing label and the SURMOUNT-1 trial (Jastreboff et al., NEJM 2022) — trials of the FDA-approved branded drug. Figures are averages, not individual predictions. Information is current as of June 2026.
What are the common tirzepatide side effects?
In Zepbound's clinical trials, the most common side effects were nausea (~25–29%), diarrhea (~19–23%), vomiting (~8–13%), and constipation (~11–17%), with abdominal pain (~9–10%) and fatigue (~5–7%) also reported. Most events occurred during dose escalation and decreased over time, improving as the body adjusted at a stable dose. These figures are sourced from the Zepbound FDA prescribing label (2025) and the SURMOUNT-1 tirzepatide trial (Jastreboff et al., NEJM 2022), which studied the branded medication. Compounded tirzepatide was not studied in those trials and is not FDA-approved.
Are Mounjaro and Zepbound side effects the same?
Yes — Mounjaro and Zepbound are both tirzepatide, manufactured by Eli Lilly. Mounjaro carries the type 2 diabetes indication and Zepbound the chronic weight management indication, but it is the same active molecule, the same formulation, and the same side-effect profile. Choosing between them in clinical practice is a labeling distinction; for compounding purposes, neither Mounjaro nor Zepbound is the reference product — compounded tirzepatide is a separate, non-FDA-approved formulation.
Does tirzepatide cause more nausea than semaglutide?
On the FDA labels, tirzepatide's nausea rate (~25–29%) reads lower than semaglutide's (~44%) from the Wegovy label and STEP 1 trial (Wilding et al., NEJM 2021) — but these are separate trials with different populations, titration schedules, and placebo rates. They were not designed as head-to-head comparisons, so a precise statement that one drug causes less nausea than the other is not supported. Tolerability is individual, and slow titration matters more than the specific drug choice.
What are the serious side effects and warnings?
Tirzepatide carries a boxed warning for thyroid C-cell tumors (observed in rodent studies; human relevance has not been determined). The drug is contraindicated in people with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Additional serious risks flagged on the label include:
- Pancreatitis — discontinue if pancreatitis is suspected
- Gallbladder disease — including cholelithiasis and cholecystitis
- Hypoglycemia — risk increases when combined with insulin secretagogues
- Acute kidney injury — typically secondary to dehydration from GI side effects
- Hypersensitivity reactions — discontinue if severe reactions occur
- Diabetic retinopathy complications — monitor patients with type 2 diabetes
For a full discussion of serious warnings across GLP-1 medications, see Serious GLP-1 Side Effects & Warnings. The NIDDK overview of prescription weight-loss medications also covers the class risk profile.
How long do Mounjaro and Zepbound side effects last?
GI side effects are typically worst in the days following a dose increase and then ease over the following 1–3 weeks as the body adjusts. At a stable maintenance dose, most people experience substantially fewer symptoms than during titration. If side effects are persistent or severe at a given dose, staying at that dose longer before the next increase is the most effective management strategy — which is why a responsive care team matters. For more on the timeline, see How Long Do GLP-1 Side Effects Last?
Tirzepatide side effects vs. semaglutide: the full picture
The two drugs are related but distinct. Semaglutide is a GLP-1 receptor agonist; tirzepatide is a dual GIP/GLP-1 receptor agonist — it activates both the GLP-1 and GIP pathways. Both slow gastric emptying and suppress appetite, which explains the similar GI side-effect profile. Neither has been shown in a randomized head-to-head to be superior in tolerability to the other.
For a parallel deep dive on semaglutide's side-effect profile, see Ozempic / Semaglutide Side Effects: The Complete List.
Related side-effect guides
- Ozempic Nausea: How to Manage It
- Serious GLP-1 Side Effects & Warnings
- Ozempic / Semaglutide Side Effects: The Complete List
How Nouri helps you manage side effects
Most GLP-1 side effects are manageable, and the single biggest factor is slow, individualized dose titration — starting low and increasing gradually. Nouri includes ongoing support from the Nouri Care Team (U.S.-licensed physicians and providers), who can slow your titration schedule, adjust your plan, and help you handle symptoms when they arise — alongside a nutrition plan that addresses the GI side effects directly by focusing on foods that sit well during early treatment.
When prescribed, Nouri provides compounded tirzepatide from $175/month on the 6-month plan ($1,050 billed every 6 months), $199/month on the 3-month plan ($597 billed every 3 months), or $225/month billed monthly — all-inclusive, any dose, same price. Compounded tirzepatide is prepared by state-licensed 503A compounding pharmacies (including Jungle Jim's Pharmacy, Fairfield, OH and VialsRX). Compounded tirzepatide is not FDA-approved and is not the same as, or therapeutically equivalent to, Zepbound or Mounjaro.
The Nouri Promise: if you are not satisfied in your first 30 days, you receive a full refund — available on 3-month and 6-month plans.
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Frequently asked questions
What are the most common side effects of Mounjaro?
Gastrointestinal: nausea (~25–29% in tirzepatide trials), diarrhea (~19–23%), vomiting (~8–13%), and constipation (~11–17%). They are usually mild-to-moderate and worst during dose increases. All figures are from trials of the FDA-approved branded drug.
What are the side effects of Zepbound?
The same as Mounjaro, since both are tirzepatide: mainly nausea, diarrhea, vomiting, and constipation, plus some abdominal pain and fatigue. Most ease over time at a stable dose.
Does tirzepatide cause more nausea than semaglutide?
By label rates, tirzepatide's nausea (~25–29%) reads lower than semaglutide's (~44%), but those are separate trials with different designs — not a head-to-head — so an exact comparison is not valid. Individual tolerance varies.
How long do Mounjaro side effects last?
Usually they are worst right after a dose increase and ease over the following weeks as your body adjusts, improving at a stable dose for most people.
Are Mounjaro and Zepbound the same?
Yes — both are tirzepatide made by Eli Lilly. Mounjaro is the diabetes label; Zepbound is the weight-loss label. Same drug, same side-effect profile.
Is Zepbound or Mounjaro better tolerated than Ozempic?
By label rates, tirzepatide's GI side effects (e.g., nausea ~25–29%) read lower than semaglutide's (~44%), but these are separate trials, not a head-to-head, so it is not a precise comparison. Tolerability is individual, and slow titration is the most effective management strategy for both drugs.
The bottom line
Mounjaro and Zepbound (tirzepatide) share a GI-dominant, dose-dependent side-effect profile — manageable with slow titration and clinical support. The Nouri Care Team helps you titrate gently and address symptoms as they arise. See if you qualify in 5 minutes.
Sources & references
- Zepbound (tirzepatide) FDA prescribing label, adverse reactions (2025) — Tier 1
- Jastreboff AM, et al. "Tirzepatide Once Weekly for the Treatment of Obesity." NEJM 2022 (SURMOUNT-1) — Tier 1
- Wegovy (semaglutide) FDA prescribing label, adverse reactions (2026) — Tier 1
- Wilding JPH, et al. "Once-Weekly Semaglutide in Adults with Overweight or Obesity." NEJM 2021 (STEP 1) — Tier 1
- NIDDK. "Prescription Medications to Treat Overweight & Obesity." National Institute of Diabetes and Digestive and Kidney Diseases — Tier 1
- FDA. "Human Drug Compounding." U.S. Food and Drug Administration — Tier 1
Medically reviewed by Amber Patel, MD. Nouri content is reviewed by licensed clinicians and updated as guidance changes. Author: Nouri Editorial Team.
This article is general information, not individual medical advice — talk to your clinician about your symptoms, and seek urgent care for the red-flag symptoms described here. Side-effect rates come from clinical trials of the FDA-approved branded medications (Wegovy, Zepbound); compounded semaglutide and tirzepatide were not studied in these trials, are not FDA-approved, and are not the same as, or therapeutically equivalent to, the brand-name drugs. GLP-1 medications carry a boxed warning for thyroid C-cell tumors and are contraindicated with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Ozempic®, Wegovy® and Rybelsus® are registered trademarks of Novo Nordisk; Mounjaro® and Zepbound® are registered trademarks of Eli Lilly; Nouri is not affiliated with these companies. Information is current as of June 2026.
Medical Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider before starting or changing any medication or treatment. Licensed providers review patient assessments before making clinical decisions.
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