Wegovy Side Effects

Wegovy is a GLP-1 receptor agonist drug, like Ozempic®. GLP-1 (glucagon-like peptide-1) is a natural satiety hormone that helps regulate insulin release and tells the body when it’s full. Receptor agonist drugs mimic natural hormones. Wegovy works by mimicking the body’s natural GLP-1 hormones to regulate insulin and satiety (feeling of fullness). The drug’s active ingredient is semaglutide.

Wegovy was approved for treating weight loss in obese patients in 2021. Since its approval, it has become hugely popular. Novo Nordisk has partnered with meal service and weight loss companies to further promote the drug.

Drugs come with side effects listed on the FDA approval label. These side effects can vary in severity and likelihood. Wegovy’s FDA approval lists several warnings, precautions and potential adverse reactions.

Common side effects of Wegovy

The most common Wegovy side effect is nausea. Other more common side effects of Wegovy include gastrointestinal issues like diarrhea and constipation.

• Abdominal distension, or swelling
• Abdominal pain
• Burping (eructation)
• Constipation
• Diarrhea
• Dizziness
• Dyspepsia, or upset stomach
• Fatigue
• Gas (flatulence)
• Gastroenteritis
• Gastroesophageal reflux disease (GERD)
• Hair loss
• Headache
• Heartburn
• Hypoglycemia
• Nausea
• Vomiting

These side effects may appear mild at first, but they can escalate in severity or because of symptoms of more serious side effects. For example, acid reflux may just be acid reflux, or it could be a warning sign of gastroparesis. All side effects should be reported to your doctor. Doctors can evaluate the severity of the condition and help you decide how to proceed.

Serious listed side effects of Wegovy

Besides the non-advertised side effects listed above, several other potentially serious conditions are associated with Wegovy.

These include:

• Acute gallbladder disease (added to warning label in March 2022)
• Acute problems
• Acute pancreatitis
• Diabetic retinopathy complications in patients with type 2 Diabetes
• Gastrointestinal obstruction
• Ileus (added to the warning label in September 2023)
• Heart rate increase
• Hypoglycemia
• Possible thyroid tumors, including cancer
• Severe allergic reactions and hypersensitivity reactions, including anaphylaxis and angioedema
• Suicidal thoughts or behavior

If you are taking Wegovy or any other GLP-1 drug like Mounjaro® or Rybelsus®, contact your doctor if you experience new or worsening side effects. These Wegovy long-term side effects may require ongoing care to treat and manage.

The U.S. Food and Drug Administration (FDA) is currently monitoring Wegovy and other semaglutide drugs for side effects, such as acute, severe and long-lasting gastrointestinal symptoms. Some alleged side effects were not listed on the original warning label for the drug. Many alleged Wegovy side effects are long-term illnesses that fundamentally change people’s lives.

As a result, some people are filing Wegovy lawsuits. These cases claim Novo Nordisk knew about the risk of Wegovy’s long-term side effects like gastroparesis and malnutrition but failed to warn users. They also claim that without accurate warning labels, patients couldn’t make informed decisions about their own health.

Vision changes and loss

NAION (nonarteritic anterior ischemic optic neuropathy) is a condition that causes vision loss because of inflammation of the arteries in the optic nerve head.

A 2024 study found that people taking semaglutide drugs like Wegovy or Ozempic were more likely to be diagnosed with NAION than other people. This study of more than 16,000 patients found that this association held for people taking the drug to manage diabetes or obesity. More studies published in early 2025 made a connection between semaglutide drugs and eye diseases. In June 2025, the World Health Organization (WHO) released a global alert regarding the risk of developing NAION while taking semaglutide drugs such as Wegovy. While this warning has been added to the Wegovy warning label in the UK, it’s still not included on the U.S. label.

Diabetic retinopathy (a type of vision loss associated with diabetes) is disclosed on semaglutide medication labels. However, NAION is a separate condition. It is possible that diabetic patients taking Wegovy or Ozempic were misdiagnosed with diabetic retinopathy.

Intestinal blockages

Intestinal obstructions (also called bowel obstructions or blockages) are not listed on Wegovy’s warning label. Obstructions keep food or liquid from moving through the digestive system normally. Blockages can be very dangerous. If untreated, they may cause intestinal tissue to die and can lead to abdominal infections.

If the intestines are fully blocked, surgery is the only way to relieve the condition. Patients who were taking Wegovy have been hospitalized for blockages.

Ileus

Ileus is a condition where the intestines can’t contract properly. This condition can cause intestinal blockages. Ileus is sometimes called gastrointestinal atony.

Ileus is listed briefly on the Wegovy warning label under the Postmarketing Experience section. This means that some patients may have been prescribed the drug before this side effect was disclosed. The label doesn’t discuss the seriousness of this condition or describe how likely patients are to experience it. 

Delayed gastric emptying, stomach paralysis, gastroparesis

Delayed gastric emptying, stomach paralysis and gastroparesis are all names for the same Wegovy side effect. It occurs when the ability of the stomach to move food (motility) slows down. This condition can lead to several other side effects and interfere with blood sugar levels and nutrient absorption.

Common symptoms of gastroparesis include:

• A feeling of fullness after eating just a few bites
• Abdominal bloating
• Abdominal pain
• Acid reflux
• Changes in blood sugar levels
• Lack of appetite
• Nausea
• Vomiting, including undigested food eaten a few hours earlier
• Weight loss and malnutrition

The drug label for Wegovy mentions “a delay of gastric emptying” in the drug interactions section. It warns that oral medication may not be absorbed properly as a result. However, it does not list the condition itself as a serious side effect. The label only mentions that Wegovy “is not recommended in patients with severe gastroparesis.” Gastroparesis should be treated seriously. If not, it can lead to hospitalization or other serious conditions like hypoglycemia and malnutrition.

Learn more about why people are filing Wegovy and Ozempic gastroparesis lawsuits.

Gastroenteritis

Gastroenteritis is an inflammation of the stomach and intestines. It can be caused by viruses and medications.

Symptoms of gastroenteritis include:

• Abdominal cramping
• Abdominal swelling
• Diarrhea
• Exhaustion
• Fever
• Loss of appetite
• Muscle aches
• Nausea

These symptoms can lead to severe dehydration as well. Gastroenteritis is listed as a potential adverse reaction on Wegovy’s label.

Malnutrition and vitamin deficiencies

One of the ways Wegovy stimulates body weight loss is by suppressing appetite. For some users, prolonged periods of taking Wegovy may lead to malnutrition. This side effect may be difficult for weight loss patients to come to terms with. However, malnutrition should be taken seriously.

Symptoms of malnutrition include:

• Brittle hair, hair loss and hair pigment loss
• Dry, inelastic skin, rashes and lesions
• Frequent and severe infections
• Irritability, apathy or inattention
• Low blood pressure
• Low body temperature
• Low heart rate
• Serious vitamin deficiencies like Wernicke Encephalopathy
• Weakness, faintness and fatigue

Muscle loss

Wegovy users may also experience extreme muscle loss. This can occur when people lose weight quickly. Severe muscle loss, or sarcopenia, can lead to death.

Some common symptoms of muscle loss could include:

• Decrease in muscle size
• Difficulty performing daily activities
• Falls
• Loss of stamina
• Poor balance
• Trouble climbing stairs
• Walking slowly

Sarcopenia can also lead to other severe side effects and conditions, including insulin resistance, reduced bone density and lowered metabolism. If you experience new or worsening symptoms while taking Wegovy, talk to your doctor right away.

Deep vein thrombosis (DVT)

Deep vein thrombosis is a condition stemming from blood clots formed deep in the body. It often occurs in the legs. DVT can spread to other areas of the body and cause potentially fatal embolisms. One study analyzed 21 clinical trials of semaglutide drugs. The researchers found semaglutide increases DVT by 226% in the trial patients.

Symptoms of DVT include:

• Changes in skin color, especially reddening or purpling
• Cramping
• Pain
• Soreness in the leg
• Swelling
• Warm feeling beneath the skin

If you are suffering from any of these symptoms, seek medical attention immediately.

The U.S. Food and Drug Administration tracks reports of negative reactions to medications on its Adverse Event Monitoring System (AEMS) Public Dashboard. At the end of 2025, there were 5,396 total reports regarding Wegovy, including 35 deaths and 1,825 reports of gastrointestinal side effects. 101 of the reports were considered life-threatening.

There are thousands more reports concerning Wegovy’s sister drugs, Ozempic® and Rybelsus®, and the generic drug, semaglutide.

*AEMS is intended to help identify safety concerns related to marketed products, but it does not prove any product or drug is linked or caused a particular side effect or injury. Reports by themselves are not an indicator of a medical product’s safety profile. In addition, AEMS may include duplicate reports or may significantly undercount injuries.

When do Wegovy side effects start?

Wegovy side effects may start to show up a couple of days to weeks after starting the medication, but this will ultimately depend on your body’s specific reaction to the drug. Some people may experience more side effects than others.

What are the worst side effects of Wegovy?

Severe side effects from Wegovy may include thyroid cancer, vision loss, gastrointestinal issues, hypoglycemia, deep vein thrombosis, malnutrition and allergic reactions. Wegovy users may or may not experience these severe side effects depending on how their bodies respond to the medication.

How long do Wegovy side effects last?

Some Wegovy side effects may resolve within a few weeks as the body adjusts to the drug. Others will continue for the entire time a patient takes Wegovy, and some will become lifelong health conditions for patients to manage. Wegovy side effect duration will vary based on the type of condition, its severity and the patient’s overall health and genetic makeup.

What are the long-term side effects of Wegovy?

Long-term side effects from Wegovy are still being researched and will vary depending on the user and their existing medical conditions. Side effects that may impact users long-term include thyroid cancer, vision and mental health changes and gastrointestinal issues.

What should I do if I experience an adverse event from Wegovy?

Adverse complications can be severe and life-altering. First, seek attention from a healthcare professional. Once you’ve received treatment from your healthcare provider, consider consulting an attorney to explore your legal options. A Wegovy lawsuit can allow you to pursue justice from the manufacturer and potentially be compensated for pain and suffering, healthcare expenses and lost wages.

Speaking with a lawyer who has experience handling litigation against medical manufacturers can help you understand your legal options.

Our medical attorneys have represented thousands of patients seriously hurt by dangerous prescription and over-the-counter drugs. We understand that as a patient or family member, your knowledge of your own or a loved one’s medications may be limited.

If you believe a medicine made you sick or hurt you, first consult your healthcare provider. Once you’ve received treatment and are getting medical advice, consider consulting Motley Rice for a case evaluation. Our attorneys have the resources needed to thoroughly investigate and:

• Identify potentially harmful medicines
• Investigate if the medicine hurt you
• Review the medicine manufacturer’s compliance with FDA regulations
• Review the adequacy of the manufacturer's warning to you about potential side effects
• Recognize other issues that could affect your potential claim

Learn more about our medical drug experience here.

Do not stop taking a prescribed medication without first consulting with your doctor. Discontinuing a prescribed medication without your doctor's advice can result in injury or death. Ozempic, Rybelsus, Wegovy and Mounjaro remain approved by the U.S. Food and Drug Administration.