Wegovy® side effects are, for most people, digestive — and the real numbers are on the label, not in a forum thread. Nausea, diarrhea, vomiting, and constipation top the adverse-reaction tables on both the Wegovy® (semaglutide) and Zepbound® (tirzepatide) weight-reduction labels. Below is a brand-by-brand breakdown of what each label actually says — where they match, where they differ, and a real nausea playbook.
Wegovy® is semaglutide (Novo Nordisk) and Zepbound® is tirzepatide (Eli Lilly), and both carry FDA labeling to reduce excess body weight and maintain weight reduction long term in adults with obesity, or in adults with overweight who have at least one weight-related comorbid condition[1]. Every claim below comes from the label for that weight indication — not a diabetes label, not a press release.
What are the side effects of Wegovy®?
On the Wegovy® (semaglutide) weight-reduction label, the adverse reactions reported in at least 2% of adults on 2.4 mg once weekly, and more often than placebo, were: nausea (44% vs 16%), diarrhea (30% vs 16%), vomiting (24% vs 6%), constipation (24% vs 11%), abdominal pain (20% vs 10%), headache (14% vs 10%), fatigue (11% vs 5%), dyspepsia — indigestion — (9% vs 3%), dizziness (8% vs 4%), abdominal distension, eructation or belching, flatulence, gastroenteritis, gastroesophageal reflux disease, gastritis, and hair loss[1].
The Wegovy® (semaglutide) weight-reduction label reports a discontinuation rate of 6.8% among adults on 2.4 mg once weekly, versus 3.2% on placebo, most often for nausea, vomiting, or diarrhea[1]. That is the honest scale of it: uncomfortable for many, disqualifying for a small minority. Individual results vary.
The Wegovy® (semaglutide) weight-management labeling carries a boxed warning for risk of thyroid C-cell tumors[1], covered below. The FDA weight-management label for semaglutide (Wegovy®) also names, among its serious adverse reactions: acute pancreatitis, acute gallbladder disease, hypoglycemia, acute kidney injury due to volume depletion, severe gastrointestinal adverse reactions, hypersensitivity reactions, diabetic retinopathy complications in patients with type 2 diabetes, heart rate increase, and pulmonary aspiration during general anesthesia or deep sedation[2][1].
What are the side effects of Zepbound®?
The Zepbound® (tirzepatide) label lists its most common adverse reactions — those reported in at least 5% of patients treated for weight reduction — as nausea, diarrhea, vomiting, constipation, abdominal pain, dyspepsia, injection-site reactions, fatigue, hypersensitivity reactions, eructation, hair loss, and gastroesophageal reflux disease[2]. The Zepbound® (tirzepatide) weight-reduction labeling also reports that gastrointestinal adverse reactions occurred in 56% of patients at each dose studied — 5 mg, 10 mg, and 15 mg — versus 30% on placebo, and that between 1.9% and 4.3% discontinued because of them, versus 0.5% on placebo[2].
The Zepbound® (tirzepatide) weight-management labeling carries the same boxed warning for risk of thyroid C-cell tumors[2]. The FDA weight-management label for tirzepatide (Zepbound®) also names, among its serious adverse reactions: severe gastrointestinal adverse reactions, acute kidney injury due to volume depletion, acute gallbladder disease, acute pancreatitis, hypersensitivity reactions, hypoglycemia, diabetic retinopathy complications in patients with type 2 diabetes, and pulmonary aspiration during general anesthesia or deep sedation.
Where the two labels actually differ
Headache appears among the adverse reactions on the Wegovy® (semaglutide) weight-reduction label and is not among the most common adverse reactions listed on the Zepbound® (tirzepatide) weight-reduction label[1]. Injection-site reactions appear among the most common adverse reactions on the Zepbound® (tirzepatide) weight-reduction label, reported in 6% to 8% of patients versus 2% on placebo; the Wegovy® (semaglutide) weight-reduction label reports injection site reactions in 1.4% of patients versus 1% on placebo, below its most-common threshold[2]. Hair loss appears among the adverse reactions on the Wegovy® (semaglutide) weight-reduction label, and hair loss also appears among the most common adverse reactions on the Zepbound® (tirzepatide) weight-reduction label. The Wegovy® (semaglutide) weight-reduction label lists heart rate increase among the serious adverse reactions it cross-references to its Warnings and Precautions; the Zepbound® (tirzepatide) weight-reduction label reports a mean heart rate increase of 1 to 3 beats per minute among its adverse reactions, without a corresponding warning[1].
The boxed warning both brands carry
The FDA weight-management label for semaglutide (Wegovy®) carries a boxed warning for risk of thyroid C-cell tumors. The FDA weight-management label for tirzepatide (Zepbound®) carries a boxed warning for risk of thyroid C-cell tumors. The FDA weight-management label for semaglutide (Wegovy®) describes dose-dependent and treatment-duration-dependent thyroid C-cell tumors in rodents at clinically relevant exposures[1]. The FDA weight-management label for semaglutide (Wegovy®) states that the human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined[1]. The FDA weight-management label for tirzepatide (Zepbound®) states that the human relevance of tirzepatide-induced rodent thyroid C-cell tumors has not been determined[2].
The FDA weight-management labels for semaglutide (Wegovy®) and tirzepatide (Zepbound®) both state that the medicine is contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)[1].
How long do GLP-1 side effects last?
The Zepbound® (tirzepatide) weight-reduction labeling is unusually direct here: the majority of nausea, vomiting, and/or diarrhea events occurred during dose escalation and decreased over time, and the majority of patients who discontinued because of adverse reactions did so during the first few months of treatment[2]. The Zepbound® (tirzepatide) weight-management labeling also gives the mechanical reason for that arc — tirzepatide delays gastric emptying, the delay is largest after the first dose, and this effect diminishes over time[2]. What the labeling supports is a pattern, not a stopwatch. Individual results vary.
Why do semaglutide and tirzepatide cause these effects?
The mechanism is on the label. The Wegovy® (semaglutide) weight-management labeling states that semaglutide delays gastric emptying, that semaglutide decreases calorie intake, and that these effects are likely mediated by affecting appetite[1]. The Zepbound® (tirzepatide) weight-management labeling says much the same of tirzepatide: it delays gastric emptying, decreases calorie intake, is described as a GIP receptor and GLP-1 receptor agonist — two gut-hormone pathways rather than one — and lowers body weight with greater fat mass loss than lean mass loss[2].
That slowed digestion is why the dose schedule looks the way it does. The Wegovy® (semaglutide) weight-management labeling initiates dosing at 0.25 mg once weekly for 4 weeks, then titrates every 4 weeks toward a usual maintenance dosage of 2.4 mg once weekly. The Zepbound® (tirzepatide) weight-management labeling starts dosing at 2.5 mg once weekly for 4 weeks, increases in 2.5 mg increments after at least 4 weeks, to a maximum dosage of 15 mg once weekly — and says plainly why that dose escalation exists: to reduce the risk of gastrointestinal reactions[2].
How do you reduce nausea on a GLP-1?
The labeling's own lever is the titration schedule — the slow ramp is the tolerability tool. Beyond that, a practical playbook: eat smaller portions, stop before you're full, and favor bland, lower-fat foods when you're queasy. Sip water steadily, skip greasy and very sweet meals, and don't lie down right after eating. Ginger or cold foods ease queasiness for some people. None of this is a guarantee — and if nausea is severe or you can't keep fluids down, that is a call to make, not a tip to try.
Low blood sugar, and other medications
The FDA weight-management labels for semaglutide (Wegovy®) and tirzepatide (Zepbound®) state that concomitant use with insulin or an insulin secretagogue — a sulfonylurea, for example — may increase the risk of hypoglycemia, including severe hypoglycemia, and that reducing the dose of the insulin or the secretagogue may be necessary[1]. The FDA weight-management label for semaglutide (Wegovy®) states that it delays gastric emptying and may impact the absorption of concomitantly administered oral medications[1]. The FDA weight-management label for tirzepatide (Zepbound®) states that it delays gastric emptying and has the potential to impact the absorption of concomitantly administered oral medications[2].
When should side effects prompt a call to your clinician?
The FDA weight-management labels for semaglutide (Wegovy®) and tirzepatide (Zepbound®) list acute pancreatitis among their serious adverse reactions, with discontinuation guidance set out in the labels' Warnings and Precautions section[1]. The FDA weight-management label for semaglutide (Wegovy®) names acute gallbladder disease among its serious adverse reactions and reports cholelithiasis and cholecystitis among the adverse reactions in its weight-reduction trials[1]. The FDA weight-management label for tirzepatide (Zepbound®) names acute gallbladder disease among its serious adverse reactions[2].
The Zepbound® (tirzepatide) label states that hypersensitivity reactions — anaphylaxis and angioedema — have been reported postmarketing, and directs patients to promptly seek medical attention and discontinue the drug; the Wegovy® (semaglutide) label lists these reactions among its serious adverse reactions and directs that the medicine be discontinued and the reaction treated promptly per standard of care[1]. The FDA weight-management labels for semaglutide (Wegovy®) and tirzepatide (Zepbound®) also direct that renal function be monitored in patients reporting adverse reactions that could lead to volume depletion[1], which is why severe or persistent vomiting and diarrhea are worth a call rather than a wait.
The FDA weight-management labels for semaglutide (Wegovy®) and tirzepatide (Zepbound®) name pulmonary aspiration during general anesthesia or deep sedation among their serious adverse reactions in patients receiving GLP-1 receptor agonists undergoing elective procedures[1] — so tell your clinician about any planned surgery. If you're weighing whether these medications fit you at all, are weight-loss shots safe is a good next read, and weight-loss shots explained covers the mechanism in plain language.
A note on compounded options
You may see compounded semaglutide or compounded tirzepatide offered through telehealth. Compounded medications are not FDA-approved; they are prepared in FDA-regulated facilities. Everything on this page is drawn from the FDA labeling for brand-name Wegovy® and Zepbound®. Any medication decision — brand or compounded — is made by your licensed clinician based on your health. Explore the category on our weight wellness hub.
The bottom line
Wegovy® (semaglutide) side effects and Zepbound® (tirzepatide) side effects overlap heavily, and the Zepbound® (tirzepatide) weight-reduction labeling states the pattern outright: gastrointestinal adverse reactions dominate, the majority of nausea, vomiting, and diarrhea events occur during dose escalation, and they decrease over time. The brand-by-brand differences are real but narrow. The serious risks, including a boxed warning for thyroid C-cell tumors on both, are less common but real. Reading what the label actually says is what makes the conversation with your clinician a good one — for more on timing, see how long side effects last.
FAQ
Are Wegovy® and Zepbound® side effects the same?
They're close. Nausea, diarrhea, vomiting, constipation, abdominal pain, dyspepsia, fatigue, eructation, hair loss, and gastroesophageal reflux disease appear among the adverse reactions on both the Wegovy® (semaglutide) and Zepbound® (tirzepatide) weight-reduction labels. Headache appears among the adverse reactions on the Wegovy® (semaglutide) weight-reduction label and is not among the most common adverse reactions on the Zepbound® (tirzepatide) weight-reduction label; injection-site reactions are among the most common adverse reactions on the Zepbound® (tirzepatide) weight-reduction label, while the Wegovy® (semaglutide) weight-reduction label reports them well below its most-common threshold. Individual results vary.
When do side effects usually peak?
The Zepbound® (tirzepatide) weight-reduction labeling reports that the majority of nausea, vomiting, and/or diarrhea events occurred during dose escalation and decreased over time, and that the majority of patients who discontinued because of adverse reactions did so in the first few months. That is why the dose starts low and steps up on a schedule.
Should I stop the medication if I feel sick?
Don't start, stop, or change any prescription on your own. Mild nausea often improves with the steps above, but severe or worsening symptoms mean you should contact your licensed clinician for guidance.
Ladies First provides marketing/advertising services. Medical services are provided by our medical provider partner, an independent network of US-licensed medical providers. All medical decisions are made by a medical provider licensed in your state (D1). This article is for general information and is not medical advice. Talk to a licensed medical provider about your situation (D4). Individual results vary (D2). Compounded medications are not FDA-approved; they are prepared in FDA-regulated facilities (D3). Wegovy® and Ozempic® are registered trademarks of Novo Nordisk; Zepbound® and Mounjaro® are registered trademarks of Eli Lilly (D5).