Ozempic Side Effects: Full List, Warning Signs and Lawsuits

The most common Ozempic side effects are nausea, vomiting, diarrhea, stomach pain and constipation. In the placebo-controlled trials behind the FDA label, nausea affected 15.8% of people on 0.5 mg and 20.3% on 1 mg (6.1% on placebo), and most stomach complaints came during the weeks when the dose was being raised. Serious side effects are less common but important: the label carries a boxed warning about thyroid C-cell tumors seen in rodents and warns about pancreatitis, gallbladder disease, kidney injury from dehydration, severe gastrointestinal reactions, low blood sugar when combined with insulin or a sulfonylurea, worsening diabetic retinopathy, serious allergic reactions and food entering the lungs during anesthesia. "Stomach paralysis," or gastroparesis, is the subject of more than 4,000 pending federal lawsuits, but no court has decided that the drug causes it.

Below: the full list with the label's numbers, how to handle the everyday side effects, the symptoms that mean you should stop and get care, and what is known about vision, mood, hair, surgery and the lawsuits as of October 2026.

Ozempic side effects at a glance

Side effect	Placebo	Ozempic 0.5 mg	Ozempic 1 mg
Nausea	6.1%	15.8%	20.3%
Diarrhea	1.9%	8.5%	8.8%
Abdominal pain	4.6%	7.3%	5.7%
Vomiting	2.3%	5%	9.2%
Constipation	1.5%	5%	3.1%
Indigestion (dyspepsia)	1.9%	3.5%	2.7%
Belching	0%	2.7%	1.1%
Acid reflux (GERD)	0%	1.9%	1.5%
Gas (flatulence)	0.8%	0.4%	1.5%
Any gastrointestinal reaction	15.3%	32.7%	36.4%
Stopped treatment because of stomach side effects	0.4%	3.1%	3.8%

Source: Ozempic prescribing information, pooled placebo-controlled trials in adults with type 2 diabetes. In a separate trial comparing doses, stomach side effects occurred in 34% of people on 2 mg and 30.8% on 1 mg.

Other effects in the label: fatigue, a changed sense of taste and dizziness (each above 0.4%); an average heart-rate increase of 2 to 3 beats per minute; mild injection-site reactions (0.2%); and rises in the pancreatic enzymes amylase (13% on average) and lipase (22%). Reports gathered after approval add bowel obstruction (ileus), severe constipation including fecal impaction, rash, hives, severe allergic reactions, gallbladder removal, a burning or tingling skin sensation (dysesthesia), headache, acute kidney injury and hair loss. Because those come from voluntary reports, their frequency is not known.

Why semaglutide drew so much attention

Ozempic, Wegovy and Mounjaro became household names because people lost weight on them, and celebrity rumors and social media videos turned a diabetes drug into a cultural shorthand for rapid weight loss. Ozempic and Wegovy both contain semaglutide, a GLP-1 receptor agonist; Mounjaro and Zepbound contain tirzepatide, which acts on two hormone receptors (GIP and GLP-1). All slow the emptying of the stomach and reduce appetite, which is both how they work and why their side effects concentrate in the gut.

Ozempic is FDA-approved for adults with type 2 diabetes. Wegovy, a higher-dose semaglutide brand, is the one approved for weight management. When people use Ozempic for weight loss, they are using it off-label, often at the top of its dose range; see Ozempic for weight loss. And when demand outran supply, the semaglutide shortage left some people with diabetes hunting for pens until the FDA declared it resolved on February 21, 2025.

How to manage nausea, diarrhea and constipation

Stomach side effects are usually worst in the first weeks and after each dose increase, then ease as the body adjusts. That is why treatment starts at 0.25 mg, a dose meant for getting used to the drug rather than for blood sugar control, and climbs no faster than every four weeks. Practical steps that help many people:

• Nausea: eat smaller meals, slowly, and stop as soon as you feel full. Go easy on fatty, fried and very sweet food. Do not lie down right after eating. Sip water through the day.
• Diarrhea: drink more fluids, and use an oral rehydration drink if it lasts. Hold back on fatty food and alcohol until it settles.
• Constipation: fluids, fiber from vegetables, beans and whole grains, and daily movement. Ask a pharmacist before using a laxative.
• Reflux and belching: finish eating two to three hours before bed and skip carbonated drinks.

If symptoms do not fade, your prescriber can keep you on a lower dose longer or step back down. Do not raise the dose faster than prescribed to "get to results" sooner. Food, drink and exercise questions are covered in Ozempic and alcohol, diet, coffee and exercise.

When to stop Ozempic and get medical care

Some symptoms are not part of adjusting to the drug. For these, do not take the next dose and contact your clinician the same day, or go to an emergency department. Call 911 for trouble breathing, swelling of the face or throat, fainting or chest pain.

Symptom	What it may mean
Severe stomach pain that will not go away, sometimes spreading to the back, with or without vomiting	Acute pancreatitis. The label says to stop Ozempic if pancreatitis is suspected.
Pain in the upper right abdomen, fever, yellow skin or eyes, pale stools	Gallstones or gallbladder inflammation
Vomiting or diarrhea that will not stop, unable to keep fluids down, little urine, dizziness	Dehydration, which can injure the kidneys; some cases have needed dialysis
Shakiness, sweating, fast heartbeat, strong hunger, confusion, especially with insulin or a sulfonylurea	Low blood sugar. Take fast-acting sugar and tell your prescriber; other diabetes drug doses may need to come down.
Sudden vision loss or rapidly worsening vision	Worsening diabetic retinopathy or, rarely, an optic nerve problem (NAION)
Swelling of the face, lips, tongue or throat, trouble breathing, widespread rash	Serious allergic reaction (anaphylaxis or angioedema). Call 911.
Bloating, cramping, unable to pass stool or gas, vomiting	Bowel obstruction
A lump in the neck, trouble swallowing, persistent hoarseness, shortness of breath	Possible thyroid tumor; tell your clinician

The boxed warning: thyroid C-cell tumors

In mice and rats, semaglutide caused thyroid C-cell tumors that depended on dose and duration. Whether it does so in people is unknown; the label says the human relevance has not been determined. For that reason Ozempic must not be used by anyone with a personal or family history of medullary thyroid carcinoma (MTC) or with multiple endocrine neoplasia syndrome type 2 (MEN 2). The label notes postmarketing reports of MTC with liraglutide, another GLP-1 drug, but says the data are insufficient to establish or exclude a causal link. Routine calcitonin blood tests or thyroid ultrasounds are of uncertain value for catching MTC early. What matters most is telling your clinician about a neck lump, trouble swallowing, shortness of breath or hoarseness that persists.

Pancreatitis, gallbladder and kidneys

In the diabetes trials, acute pancreatitis confirmed by an independent committee occurred in 7 people on Ozempic (0.3 cases per 100 patient-years) compared with 3 on other treatments (0.2 per 100 patient-years). Postmarketing reports include fatal necrotizing pancreatitis. Gallstones were reported in 1.5% of people on 0.5 mg and 0.4% on 1 mg, and in none on placebo. Kidney injury usually follows dehydration from vomiting or diarrhea, which is why the label asks clinicians to monitor kidney function in people with those symptoms, especially while the dose is rising.

Gastroparesis and the "stomach paralysis" lawsuits

Gastroparesis means the stomach empties very slowly without a physical blockage, causing early fullness, nausea, vomiting of undigested food, bloating and pain. Slowing the stomach is part of how semaglutide works, so the question is when a drug effect becomes a disorder. In October 2025, the FDA-approved label gained a warning section titled "Severe Gastrointestinal Adverse Reactions": in the trials, severe stomach reactions occurred in 0.4% of people on 0.5 mg and 0.8% on 1 mg versus 0% on placebo, and Ozempic is not recommended for people who already have severe gastroparesis.

The research is mixed. A 2023 research letter in JAMA, using health-insurance claims, reported higher risks of pancreatitis, bowel obstruction and gastroparesis among people using GLP-1 drugs for weight loss than among those using bupropion-naltrexone; the absolute risks were low and a claims study cannot prove cause. Diabetes itself is a leading cause of gastroparesis, which makes untangling drug from disease hard.

In the courts, lawsuits against Novo Nordisk and Eli Lilly over gastrointestinal injuries from GLP-1 drugs, including Ozempic, Wegovy, Rybelsus, Mounjaro and Trulicity, are consolidated before Judge Karen S. Marston in the U.S. District Court for the Eastern District of Pennsylvania as MDL No. 3094. As of October 1, 2026, 4,025 actions were pending there, and a separate MDL No. 3163 over the optic nerve condition NAION had 247 pending, according to the Judicial Panel on Multidistrict Litigation. Plaintiffs claim the companies failed to warn adequately; the companies deny the claims. No verdict has established that semaglutide causes gastroparesis.

Surgery, endoscopy and anesthesia

Because semaglutide slows the stomach, food can remain even after the usual fasting. The label warns of rare reports of pulmonary aspiration, stomach contents entering the lungs, in people on GLP-1 drugs who had general anesthesia or deep sedation, despite following fasting instructions. It says available data are not enough to recommend a specific fix, and asks patients to tell their clinicians before any planned procedure.

Guidance issued on October 29, 2024 by the American Society of Anesthesiologists with four other societies says most patients can keep taking GLP-1 drugs before elective surgery. Those at higher risk are people still in the dose-escalation phase (typically the first 4 to 8 weeks), whose elective surgery should be deferred until it passes; people with active nausea, vomiting, abdominal pain or constipation; and people on higher doses, who should follow a liquid diet for 24 hours before the procedure. Anesthesiologists may also use a bedside ultrasound to check the stomach. Tell your surgeon, gastroenterologist and anesthesiologist that you take Ozempic, and follow the instructions you are given.

Vision: diabetic retinopathy and NAION

In the two-year SUSTAIN-6 cardiovascular trial, complications of diabetic retinopathy (such as the need for laser treatment or eye injections, or bleeding inside the eye) occurred in 3.0% of people on Ozempic and 1.8% on placebo. The increase was larger in people who already had retinopathy (8.2% vs 5.2%) than in those who did not (0.7% vs 0.4%). Rapid improvement in blood sugar can temporarily worsen retinopathy, so people with a history of it should keep regular eye exams.

Non-arteritic anterior ischemic optic neuropathy (NAION) is a sudden loss of blood flow to the optic nerve that can cause permanent vision loss in one eye. On June 6, 2025, the European Medicines Agency's safety committee concluded that NAION is a very rare side effect of semaglutide, affecting up to 1 in 10,000 users, with studies in adults with type 2 diabetes suggesting roughly double the risk, about one extra case per 10,000 person-years of treatment. The U.S. Ozempic label we reviewed (revised October 2025) does not list NAION. The practical advice is the same on both sides of the Atlantic: sudden vision loss or fast-worsening eyesight needs prompt medical attention.

Mood, depression and suicidal thoughts

In 2023, regulators began reviewing reports of suicidal thoughts in people taking GLP-1 drugs. On January 11, 2024, the FDA said its preliminary evaluation had found no evidence that these medicines cause suicidal thoughts or actions, while noting it could not fully rule out a small risk. The agency later announced, on January 13, 2026, that it was requesting removal of the suicidal behavior and ideation warning from GLP-1 medicines whose labels carried one. Ozempic's own label does not list mood effects.

That does not mean mood never changes during treatment. Persistent nausea, eating much less, a changing body and the burden of a chronic illness can all weigh on people. Tell your clinician about new or worsening depression, anxiety or unusual mood changes, and do not stop the medicine on your own. If you are in crisis, call or text 988 for the Suicide and Crisis Lifeline, available 24 hours a day.

Hair loss, heart rate and other questions

• Hair loss: listed among postmarketing reports for Ozempic. In weight-management trials of higher semaglutide doses it was more common than with placebo, and it is usually linked to rapid weight loss, a temporary shedding that tends to recover. Eating enough protein matters; see Ozempic face for skin and hair changes and iron supplements if a deficiency is suspected.
• Heart rate: an average rise of 2 to 3 beats per minute. Tell your clinician if you notice a racing or pounding heartbeat at rest.
• Fatigue and dizziness: often tied to eating and drinking less; fluids and regular small meals help.
• Injection-site reactions: uncommon; rotate sites within the abdomen, thigh or upper arm each week.

Who should not take Ozempic, or needs extra caution

• Do not use: personal or family history of medullary thyroid carcinoma, MEN 2, or a prior serious allergic reaction to semaglutide or its ingredients.
• Pregnancy: the label advises stopping at least two months before a planned pregnancy because semaglutide takes weeks to leave the body.
• Type 1 diabetes: Ozempic is not a substitute for insulin and is not for diabetic ketoacidosis.
• Past pancreatitis: discuss carefully; stop if pancreatitis is suspected.
• Diabetic retinopathy: needs eye monitoring.
• Severe gastroparesis: Ozempic is not recommended.
• Insulin or sulfonylurea users: higher risk of low blood sugar; doses of those drugs may need to be lowered.
• Kidney disease: guard against dehydration during stomach upsets.

Weighing the risks against the benefits

For people with type 2 diabetes, the benefits are documented. In SUSTAIN-6, heart attack, stroke or cardiovascular death occurred in 6.6% of people on Ozempic versus 8.9% on placebo over about two years, and the FLOW kidney trial showed a 24% lower risk of major kidney outcomes and cardiovascular death. Those results are why the label carries heart and kidney indications; see Ozempic for type 2 diabetes and what else semaglutide is being studied for.

For people without diabetes using Ozempic off-label for weight, the benefit-risk balance has not been studied at Ozempic's doses; weight management is what Wegovy's trials examined. Long-term data keep accumulating, and regulators have added warnings as they emerged: severe gastrointestinal reactions, aspiration during anesthesia and, in Europe, NAION. Patients who know the warning signs and keep in touch with their prescriber are in the best position to catch problems early.

How to report a side effect

You, your pharmacist or your clinician can report a suspected side effect to the FDA's MedWatch program online or by fax at 1-800-FDA-0178, or to Novo Nordisk at 1-888-693-6742, the number on the label. Reports help regulators spot rare problems that trials are too small to detect. For the rest of our guide, see Ozempic, Ozempic dosage and Ozempic vs Mounjaro. This article is general information, not medical advice.