Wegovy Safety Guide

Wegovy side effects: what the data actually shows

Published by GLP-1 Picks · AI-assisted editorial research · Updated October 23, 2026

The most common Wegovy side effects are gastrointestinal: nausea (44%), diarrhea (30%), vomiting (24%), and constipation (24%) in the cited adult 2.4 mg injection trials.

These trial averages do not predict your symptoms or when they will occur. All percentages below come from the FDA-approved Wegovy prescribing information, not marketing materials.

Warning signs: when to seek medical help

• Severe abdominal pain that does not go away, with or without vomiting: stop Wegovy and contact your healthcare professional right away; pain may reach your back.
• Symptoms of a serious allergic reaction, such as breathing difficulty or throat swelling: stop Wegovy and get medical help right away.
• Persistent nausea, vomiting, or diarrhea: contact your clinician promptly about possible dehydration; do not wait for a fixed number of hours.
• Upper abdominal pain, fever, jaundice, or clay-colored stools: contact your clinician about possible gallbladder problems.

If you are experiencing a medical emergency, call 911.

Report any serious adverse event to FDA MedWatch.

Common side effects: rates from the Wegovy label

Source: section 6.1, Table 3 of the FDA-approved Wegovy prescribing information.

These are pooled adult 2.4 mg injection trials for weight reduction, not rates for oral Wegovy, every injection dose or pediatric use. They do not describe a symptom's severity or duration.

Side effect	Rate
Nausea	44%
Diarrhea	30%
Vomiting	24%
Constipation	24%
Abdominal pain	20%
Headache	14%
Fatigue	11%
Dyspepsia (indigestion)	9%
Dizziness	8%
Hair loss	3%

How do dose changes affect symptoms?

Reported nausea, vomiting and diarrhea can occur during dose increases. Trial percentages do not tell you which week a symptom will start or stop.

Follow your prescriber's instructions for your exact product and indication, and contact them about troublesome symptoms before changing your dose.

The Wegovy prescribing information, section 2 explains the dosing instructions. It is a reference for your clinician, not a schedule to advance through automatically.

What should you ask your prescriber about side effects?

Describe the symptom, when it started, your current dose and your most recent dose change.
Explain whether eating, drinking or daily activities are affected. Persistent or severe symptoms need clinical assessment.
For routine symptoms, ask your clinician before changing Wegovy, insulin or sulfonylureas. Follow the urgent instructions above if those warning signs occur.
Ask which symptoms require urgent help and how to contact the care team between appointments.

Use the Wegovy prescribing information and Medication Guide alongside this checklist. For help recording symptoms and preparing questions, see our symptom-management guide.

FDA's January 2026 review found no increased risk of suicidal thoughts or behavior with GLP-1 medicines.

Mood changes still deserve care: tell your clinician about new or worsening depression or suicidal thoughts. Call or text 988 for crisis support; call 911 for immediate danger.

Serious side effects, recognize these red flags

This is not a complete list of warnings or possible side effects. Use the full prescribing information and Medication Guide with your clinician. A trial percentage cannot tell you whether a symptom is safe to ignore.

Pancreatitis

Reported in clinical trials; requires urgent assessment

Red-flag symptoms: Severe or persistent abdominal pain that may reach your back, with or without nausea or vomiting

Action: Stop Wegovy and contact your healthcare professional right away if pancreatitis is suspected.

Gallbladder problems

Adult injection trials: gallstones 1.6% (placebo 0.7%); cholecystitis 0.6% (placebo 0.2%)

Red-flag symptoms: Upper abdominal pain, fever, jaundice, or clay-colored stools

Action: Contact your clinician promptly for these symptoms. They can assess whether gallbladder tests and follow-up are needed.

Kidney injury (acute)

Reported, including after fluid loss from vomiting or diarrhea

Red-flag symptoms: Persistent nausea, vomiting, or diarrhea that can lead to dehydration

Action: Contact your clinician promptly for ongoing vomiting or diarrhea, trouble keeping fluids down, or signs of dehydration. Do not wait for a fixed number of hours.

Hypoglycemia

Risk is increased in people with type 2 diabetes, especially with insulin or sulfonylureas

Red-flag symptoms: Shakiness, sweating, confusion, rapid heartbeat, blurred vision

Action: Follow the low-blood-sugar plan agreed with your clinician. Contact them about symptoms and ask whether your medicines need review.

Severe allergic reaction (anaphylaxis)

Reported; can be life-threatening

Red-flag symptoms: Difficulty breathing or swallowing, swelling of the face, lips, tongue or throat, severe rash or itching, or faintness

Action: Stop Wegovy and get medical help right away for a suspected serious allergic reaction.

The boxed warning: thyroid C-cell tumors

Wegovy carries a boxed warning for thyroid C-cell tumors. This is based on rodent studies; the human risk is unknown.

Wegovy is contraindicated in patients with:

• Personal or family history of medullary thyroid carcinoma (MTC)
• Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)
• A known serious allergic reaction to semaglutide or any Wegovy ingredient

Tell your prescriber about your personal and family thyroid history and any serious medication allergies before starting Wegovy.

Choosing a provider who handles side effects well

Ask about access to clinical support before starting Wegovy:

Does the provider respond within hours or days?
Will they hold dose escalation if you're struggling, or push you to the next dose?
What monitoring does the clinician recommend for your medical history and symptoms, and what does it cost?

Compare each program's current clinical-oversight evidence in our full rankings.

Overall scores incorporate price, medication options, experience, and transparency as well as oversight; they are not a medical-safety endorsement.

Ask about access to clinical support before you start and whenever symptoms or dose changes need review.

Explore program costs and recorded support options in the program finder, or take the 60-second match quiz to explore program options.

Zepbound side effects deep dive , for users comparing the two
Ozempic side effects deep dive , same molecule (semaglutide) at the diabetes doses
Foundayo side effects deep dive
Mounjaro side effects deep dive , tirzepatide at the diabetes indication
Cross-drug GLP-1 side effects comparison , Wegovy vs Zepbound vs Foundayo vs Rybelsus rates side-by-side
Wegovy vs Zepbound: cost, side effects, and weight loss
Wegovy and Ozempic lawsuit tracker
FDA warning letter tracker
Provider safety checker , questions and checks to use before enrolling

Sources

This page is for informational purposes only and is not medical advice. Always discuss medication decisions with a licensed prescriber.

Side-effect rates are population averages from clinical trials and may not reflect your individual experience. If you are experiencing a medical emergency, call 911.