Ozempic (Semaglutide)

Ozempic (semaglutide) is a prescription medicine used to treat Type 2 diabetes in adults and certain heart and kidney risks in people with Type 2 diabetes and heart or kidney conditions. It’s part of a class of drugs called GLP-1 receptor agonists. Other drugs in this class include Mounjaro, Rybelsus and Wegovy. These drugs work by mimicking a natural hormone that helps control blood sugar and appetite.

The U.S. Food and Drug Administration (FDA) first approved Ozempic in 2017 for the treatment of adults with Type 2 diabetes. It helps lower blood sugar by increasing insulin release and lowering the hormone glucagon when blood sugar levels are high. It also slows the rate at which food leaves the stomach, which can reduce hunger and contribute to weight loss.

Although the FDA has not approved Ozempic for weight loss, doctors have prescribed it off-label for this purpose. Another semaglutide injection, Wegovy, is FDA-approved for this purpose. The term “off-label use” refers to prescribing a medication to treat a condition for which the drug is not FDA-approved.

People prescribed Ozempic self-administer it once a week as an injection under the skin. Doctors usually start patients on an Ozempic dosage of 0.25 mg once a week and increase that to 0.5 mg after four weeks. You typically inject it yourself in the thigh, abdomen or upper arm. You should take Ozempic in conjunction with a healthy diet and exercise plan.

Ozempic is only available by prescription, and the FDA recommends that you purchase it only from a licensed pharmacy. Like all medications, it can have side effects, so it’s essential to use Ozempic under a doctor’s care.

Side Effects of Ozempic

Researchers identified the common Ozempic side effects during seven clinical trials prior to FDA approval. These trials focused strictly on people with type 2 diabetes. Some compared those using Ozempic to those taking a placebo, and one compared Ozempic use to the use of other antidiabetic drugs. Studies ran for 30 to 104 weeks.

Common side effects, defined as affecting at least 5% of people in clinical trials, are listed on Ozempic’s label.

After Ozempic’s approval, some patients and doctors reported serious side effects. Novo Nordisk and the FDA conduct post-marketing studies to monitor these effects. Independent researchers have also identified potential links to serious side effects.

Studies in rats have tied semaglutide to thyroid C-cell tumors. Though whether this is the case for humans remains unknown, the FDA has included a warning about this on Ozempic’s label.

Lawsuits against the manufacturer of Ozempic and other GLP-1 medications also claim Ozempic use resulted in injuries including gastroparesis, ileus, other gastrointestinal issues and NAION.

What Should You Do if You Experience Ozempic Side Effects

If you notice any side effects while using Ozempic, what you should do depends on what kind of symptoms you have and how bad they are.

Look out for symptoms of severe side effects. These may include persistent stomach pain, changes in your vision, swelling in your neck, difficulty breathing or symptoms of low blood sugar, such as shaking or confusion. You should also seek help if you have nonstop vomiting or diarrhea, signs of an allergic reaction or pain in your upper stomach, especially with a fever or yellowing of your skin.

If the side effects are mild — such as nausea, vomiting and diarrhea — you may want to talk to your doctor on your next visit. But beware that these problems may lead to dehydration and kidney damage if they persist.

If you develop severe gastrointestinal side effects such as gastroparesis, intestinal blockages or vision problems, you may want to speak to an attorney. These injuries are at the heart of Ozempic lawsuits currently underway.

Ozempic and other GLP-1 drugs have been linked to gastroparesis and blockages in the intestines. In addition to medical studies showing a potential connection, hundreds of lawsuits claim the medications have caused severe gastrointestinal injuries.

“These medications slow how fast food empties the stomach,” Dr. Lauren Cunningham, a clinical pharmacist and pharmacy professor at the University of Illinois Chicago, told Drugwatch. “So, avoiding an active gastroparesis is important to prevent issues like bowel obstructions.”

She said it’s important to tell your doctor as soon as you notice side effects so they don’t get worse.

In 2023, the FDA updated Ozempic’s label with a warning for the risk of ileus (intestinal blockage). The decision followed 33 reports of blockages from semaglutide users, including two deaths.

An October 2023 research letter in the Journal of the American Medical Association (JAMA) found that people using GLP-1 medications, like Ozempic, for weight loss may have a higher risk of stomach issues compared to those taking a different drug, Contrave (bupropion-naltrexone). These issues included pancreatitis, gastroparesis and bowel obstruction. While these side effects are rare, the researchers noted that the risk of those gastrointestinal issues is about three to four times higher for GLP-1 users compared to those not taking them. (The risk of pancreatitis is about nine times higher.)

Ozempic Lawsuits Claim Gastrointestinal Injuries

As of August 2025, there are 2,190 Ozempic and GLP-1 lawsuits pending in a Pennsylvania federal court. The lawsuits, initially filed around the United States, were consolidated into a single multidistrict litigation (MDL) there. An MDL allows several similar lawsuits to be consolidated to expedite the legal process.

Lawsuits in the MDL claim GLP-1 drugs — including Ozempic, Wegovy, Rybelsus, Trulicity and Mounjaro — caused gastrointestinal injuries.

They argue that the makers of each of these drugs should have known about the risks and warned the users. Novo Nordisk makes Ozempic, Wegovy and Rybelsus. Trulicity and Mounjaro are manufactured by Eli Lilly and Company.

Although there have been no trials, verdicts or settlements in the MDL, attorneys continue to accept cases, and the number of lawsuits remains steady.

Multiple studies since 2024 have indicated a potential link between taking semaglutide — the active ingredient in Ozempic, Wegovy and Rybelsus — and an increased risk of developing NAION. NAION (non-arteritic anterior ischemic optic neuropathy) is a severe eye condition where a person experiences sudden, painless vision loss in one eye, often when they wake up. It’s caused by a lack of blood flow to the optic nerve. The severity of vision loss doesn’t generally change much after onset, but it is permanent.

A 2024 study of over 16,000 patients, published in JAMA Ophthalmology, showed that people with Type 2 diabetes or obesity taking semaglutide may have a higher risk of developing NAION. This risk was significantly greater than for those on other medications.

Another study in Denmark followed more than 424,000 people with Type 2 diabetes for five years. Results were published in the International Journal of Retina and Vitreous in 2024. It found that those taking once-weekly semaglutide had more than double the risk of developing NAION than people not taking the medication. The risk stayed high even after accounting for age, blood sugar levels and other health issues.

In 2025, a large international study of over 37 million people with Type 2 diabetes found a slight increase in the risk of NAION among those taking semaglutide. The increased risk was lower than seen in earlier studies, but still present. Researchers writing in JAMA Ophthalmology stated that more studies are needed to understand how semaglutide may affect the eyes and to identify which patients are most at risk.

European Union Recommended NAION Warnings

The European Medicines Agency (EMA) — the European Union’s counterpart to the U.S. Food and Drug Administration (FDA) — reviewed studies on the potential link between NAION and the use of semaglutide.

In June 2025, the EMA found that adults with Type 2 diabetes taking semaglutide have roughly double the risk of developing NAION compared to those not using the medication. This comes to one extra case for every 10,000 people taking semaglutide each year. The EMA recommended label changes for the drugs sold in the EU to include NAOIN as a ”very rare” side effect.

Lawsuits Claim Ozempic, Wegovy Caused NAION

Since the first studies on a potential Ozempic link to NAION, attorneys started filing Ozempic lawsuits claiming NAION injuries. Several lawsuits have been filed in New Jersey state court where lawyers are seeking to have them consolidated into a multicounty litigation (MCL). An MCL is similar to an MDL, but it takes place in New Jersey’s state court system instead of a federal court and only includes cases that were pending within different parts of that state.

“There are obviously other risks that are warned about with taking Ozempic or Wegovy, but a lot of those risks are temporary in nature. Whereas if you develop NAION while on this medication, it will likely result in permanent visual impairment,” Danielle Gold, an attorney with Weitz & Luxenberg, told Drugwatch.

She said people who developed NAION after taking Ozempic or Wegovy for either Type 2 diabetes or weight loss may qualify for one of these lawsuits.

Since Ozempic was first approved, the FDA has repeatedly highlighted the potential risks associated with the medication, including thyroid tumors, inflammation of the pancreas, digestive issues and interactions with other medicines. In recent years, the FDA has also raised concerns about counterfeit or adulterated versions of the drug, emphasizing the importance of using only products approved by the FDA to ensure safety and prevent serious health issues.

Initial Warnings and Precautions

The original label for Ozempic included several warnings and precautions. It included a black box warning — the FDA’s most serious kind — that people with a personal or family history medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) should not take Ozempic. And it listed the common side effects such as stomach pain and constipation.

Additionally, it mentioned that Ozempic can slow down digestion, which might impact how other oral medications work. The label also warned people planning to get pregnant, to stop using Ozempic at least two months beforehand.

These warnings and precautions remained consistent in subsequent FDA label updates, with continued emphasis on the risks of thyroid tumors, pancreatitis and gastrointestinal side effects.

The FDA also maintained guidance for healthcare providers and patients to report suspected adverse reactions via the MedWatch program.

FDA Warns of Unapproved Versions of GLP-1 Drugs

As GLP-1 drugs became more popular for weight loss, manufacturers had difficulty meeting demands. In fact, there were official shortages of Ozempic and Webovy starting in 2022. While these drugs were in short supply, compounding pharmacies filled the void by selling compounded GLP-1 medications. Compounding pharmacies range from small, specialty pharmacies to larger operations capable of mass-producing specific medications. Though the FDA recognizes that certain compounded medications are the only option for some people, compounded drugs aren’t FDA-approved.

The FDA removed Ozempic and other semaglutide medications from the shortage list in February 2025. 

In May 2025, the FDA issued a warning to the public about the risks associated with using unapproved or compounded versions of semaglutide for weight loss. The agency pointed out that the FDA has not reviewed these products for safety, quality or effectiveness. The FDA found that some compounded semaglutide products have caused serious side effects, including nausea, vomiting and even hospitalizations due to dosing mistakes. 

The FDA has also found that some versions use salt forms of semaglutide (semaglutide sodium and semaglutide acetate), which are not approved and may not work as expected because they have a different active ingredient. . To stay safe, the FDA recommended people should only use FDA-approved semaglutide, get it from a licensed pharmacy and talk to their doctor about proper dosing.