What Does the FDA Say About Ozempic Side Effects and GLP-1 Safety?

The FDA’s safety positions on Ozempic, Wegovy and other GLP-1 drugs are written into the official prescribing information, and those labels have changed repeatedly since semaglutide was first approved in 2017 ^[1][10]. The Wegovy label’s boxed (“black box”) warning covers thyroid C-cell tumors, and it rests on rodent studies whose relevance to humans has not been determined ^[1]. Since then the FDA has added a class-wide warning on pulmonary aspiration during anesthesia (November 2024) ^[2][3], built up warnings on severe gastrointestinal reactions ^[6][15], and on January 13, 2026 asked manufacturers to remove the suicidal thoughts warning after a review found no increased risk ^[4].

One thing the FDA has not done, as of September 2026, is add a U.S. warning on NAION, the sudden-vision-loss condition that European, UK and Australian regulators have added to their product information ^{[5][13][14][16]}. The FDA has also warned that it does not review compounded semaglutide or tirzepatide for safety before they are sold ^[7], and it sent Novo Nordisk a warning letter in March 2026 over how the company handled adverse event reports — a letter that made no conclusion about the safety of the medicines themselves ^[19][20].

Where do the FDA’s safety positions actually live?

The FDA’s positions appear in the prescribing information (the label) for each product, which the agency approves and revises. The Wegovy label shows the structure: a boxed warning at the top, a “Recent Major Changes” box that lists which sections changed and in what month, a Warnings and Precautions section, and a Postmarketing Experience section (6.2) listing reactions reported after approval ^[1].

The Recent Major Changes box on the current Wegovy label shows three safety edits: acute kidney injury due to volume depletion (5.5) in August 2025, severe gastrointestinal adverse reactions (5.6) in October 2025, and removal of the suicidal behavior and ideation warning (5.10) in January 2026 ^[1].

The postmarketing section comes with an important caveat, one that appears on the Wegovy label and was repeated in the FDA’s 2023 Ozempic ileus labeling change: reactions there are reported voluntarily from a population of uncertain size, so it is not always possible to reliably estimate their frequency or establish a causal relationship to the drug ^[1][9]. In other words, a reaction appearing in section 6.2 means someone reported it — not that the FDA has concluded the drug caused it.

Does Ozempic have a black box warning?

The Wegovy (semaglutide) prescribing information carries a boxed warning about the risk of thyroid C-cell tumors ^[1]. The warning states that in rodents, semaglutide causes thyroid C-cell tumors at clinically relevant exposures, and that it is unknown whether the drug causes medullary thyroid carcinoma (MTC) in humans, because the human relevance of the rodent tumors has not been determined ^[1].

The Wegovy label contraindicates the drug in two situations: a personal or family history of MTC, or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2); and known hypersensitivity to semaglutide or any of the product’s excipients ^[1]. When the FDA approved the higher-dose Wegovy HD in March 2026, its announcement restated that the boxed warning is based on findings in rodent studies ^[8].

The FDA has never concluded that these tumors occur in humans. The warning exists because the rodent signal has not been ruled out, not because human cases have been established ^[1].

What warnings are on the current Wegovy label?

The Warnings and Precautions section of the current Wegovy label lists, in order: acute pancreatitis (5.2), with the label directing that the drug be discontinued if pancreatitis is suspected; acute gallbladder disease (5.3); hypoglycemia when used with insulin or an insulin secretagogue (5.4); acute kidney injury due to volume depletion (5.5); severe gastrointestinal adverse reactions, with a statement that the drug is not recommended in patients with severe gastroparesis (5.6); hypersensitivity reactions including anaphylaxis and angioedema (5.7); diabetic retinopathy complications in patients with type 2 diabetes (5.8); heart rate increase (5.9); and pulmonary aspiration during general anesthesia or deep sedation (5.10) ^[1].

The most common adverse reactions, those reported at a rate of 5 percent or more, include nausea, diarrhea, vomiting, constipation, abdominal pain, dysesthesia (altered skin sensation), headache, fatigue, dyspepsia, dizziness and hair loss ^[1]. The label also notes that Wegovy delays gastric emptying and may affect the absorption of oral medications taken at the same time (7.2) ^[1].

Why is there an anesthesia warning on GLP-1 drugs?

On September 6, 2024, the FDA sent Novo Nordisk a letter under section 505(o)(4) of the Federal Food, Drug, and Cosmetic Act, notifying the company of new safety information it had determined should be included in the labeling of all GLP-1 receptor agonist products: the serious risk of pulmonary aspiration for patients undergoing elective surgeries or procedures requiring general anesthesia or deep sedation ^[2].

The Ozempic labeling supplement that resulted, S-032, was approved on November 1, 2024 ^[2]. On November 5, 2024, the updated labels covered the whole class: semaglutide (Ozempic, Rybelsus, Wegovy), liraglutide (Saxenda, Victoza) and tirzepatide (Mounjaro, Zepbound) ^[3].

The new label text describes rare postmarketing reports of pulmonary aspiration in patients who had residual gastric contents despite reporting that they followed preoperative fasting instructions. It also states that available data are insufficient to say whether changing fasting recommendations or temporarily stopping the drug would reduce the incidence of retained gastric contents ^[3]. The label’s instruction to patients is to inform their healthcare providers before any planned surgery or procedure that they are taking a GLP-1 drug ^[1][3].

What did the FDA say about ileus and intestinal obstruction?

The gastrointestinal warnings were built up in steps. On September 20, 2023, the FDA added ileus — a blockage that keeps food or liquid from passing through — to the Ozempic label, based on voluntarily reported events; the same day it updated the hypoglycemia language for patients using insulin or an insulin secretagogue ^[9].

At that point, the FDA’s Adverse Event Reporting System (FAERS) dashboard showed 2,951 Ozempic adverse event cases in 2023 as of June 30, 2023, of which 1,274 were gastrointestinal. Within those reports were 6 cases of ileus, 2 of them resulting in hospitalization ^[9].

Later changes broadened the warning across the class. On November 27, 2024, the FDA approved a Wegovy supplement adding subsection 5.6, Severe Gastrointestinal Adverse Reactions, to align Wegovy with the other GLP-1 labels ^[15]. On October 14, 2025, the FDA approved Ozempic supplements S-035 and S-037, which added a statement that severe gastrointestinal reactions have also been reported postmarketing with GLP-1 receptor agonists, and added intestinal obstruction, severe constipation including fecal impaction, acute kidney injury and headache to the Ozempic postmarketing section ^[6].

The current Wegovy postmarketing section lists ileus, intestinal obstruction, severe constipation including fecal impaction and acute kidney injury, alongside acute and necrotizing pancreatitis, hypersensitivity reactions and pulmonary aspiration ^[1].

These label changes are regulatory actions, and they are separate from the courtroom. A multidistrict litigation, MDL 3094, was established in February 2024 in the Eastern District of Pennsylvania before Judge Karen S. Marston, combining claims about gastroparesis, ileus and intestinal obstruction against Novo Nordisk and Eli Lilly, with about 4,000 or more cases pending as of September 2026 ^[13]. An MDL is a consolidation of lawsuits for pretrial purposes — it is not a regulatory finding that any drug caused any injury.

Did the FDA conclude that Ozempic causes suicidal thoughts?

No — the FDA concluded the opposite and removed the warning. In July 2023, after receiving postmarketing reports of suicidal ideation and behavior in patients taking GLP-1 drugs, the FDA began an investigation ^[4]. In January 2024 it issued a Drug Safety Communication stating that its preliminary review had not found evidence that these medicines cause suicidal thoughts or actions, while noting that the small number of cases meant it could not definitively rule out a small risk, so the review continued ^[10][4].

On January 13, 2026, the FDA announced the outcome: a comprehensive review found no increased risk of suicidal ideation and behavior with GLP-1 receptor agonists, and the FDA requested that the warning language be removed from the labels of Saxenda, Wegovy and Zepbound — the weight-loss-indicated products that carried it ^[4]. The labeling of GLP-1 receptor agonists approved to improve blood sugar control or other complications in patients with type 2 diabetes does not currently include information on the risk of suicidal ideation and behavior ^[4].

The FDA noted that the original warning text came from the labeling of other types of weight-loss medicines, based on events observed with a variety of older drugs used or studied for weight loss — not from GLP-1 data ^[4][10]. The Wegovy label’s Recent Major Changes box now shows Suicidal Behavior and Ideation (5.10) as removed in January 2026 ^[1].

The FDA still advises patients to tell a healthcare professional about new or worsening depression, suicidal thoughts, or unusual changes in mood or behavior, and points to the 988 Lifeline (call or text 988), which provides free support 24 hours a day, 7 days a week ^[4][10].

What evidence was behind the January 2026 decision?

The FDA’s review rested on three bodies of evidence. First, a meta-analysis of 91 placebo-controlled GLP-1 trials including 107,910 patients — 60,338 treated with a GLP-1 receptor agonist and 47,572 with placebo. It found no increased risk of suicidal ideation or behavior, and no increased risk of anxiety, depression, irritability or psychosis ^[4].

Second, a retrospective cohort study using the FDA Sentinel System’s administrative claims data, covering 2,243,138 new users — 1,161,983 starting a GLP-1 receptor agonist and 1,081,155 starting an SGLT2 inhibitor — across 10 data partners between October 1, 2015 and September 20, 2023. After controlling for baseline differences, the FDA found no increased risk of intentional self-harm in GLP-1 users, including in the subgroup with both type 2 diabetes and obesity ^[4].

Third, the FDA reviewed published observational and pooled studies and concluded that the totality of that evidence does not support a causal relationship between GLP-1 drugs and suicidal ideation and behavior ^[4].

Has the FDA warned that Ozempic can cause blindness?

Not in the United States, as of September 2026. The condition in question is NAION — non-arteritic anterior ischemic optic neuropathy — which involves reduced blood flow to the front of the optic nerve and typically causes sudden, painless vision loss, usually in one eye ^[14][13].

On June 6, 2025, the European Medicines Agency’s safety committee (PRAC) concluded that NAION is a very rare side effect of semaglutide, meaning it may affect up to 1 in 10,000 people taking it, and recommended adding NAION to the product information for Ozempic, Rybelsus and Wegovy, with treatment stopped if NAION is confirmed ^[5]. The EMA cited epidemiological studies suggesting approximately a two-fold increase in risk in adults with type 2 diabetes, corresponding to roughly one additional case per 10,000 person-years of treatment ^[5].

No NAION warning appears on the U.S. Ozempic, Wegovy or Rybelsus labels as of September 2026, according to a litigation-tracking site that follows the federal cases ^[13]. Consistent with that, the current Wegovy label’s postmarketing section lists only gastrointestinal, hypersensitivity, pulmonary aspiration and renal entries ^[1]. The absence of a warning is not a statement that the FDA has rejected one — it means no U.S. label change has been made.

What have other regulators done about NAION?

The UK, Australia and Canada have all acted, in different ways and on different timelines.

Regulator	Date	Action
EMA (Europe)	June 6, 2025	Concluded NAION is a very rare side effect of semaglutide (up to 1 in 10,000); recommended adding it to Ozempic, Rybelsus and Wegovy product information [5]
MHRA (UK)	February 5, 2026	Updated product information on the very rare risk; three Yellow Card reports up to August 1, 2025, against roughly 10.2 million packs dispensed in five years [14]
TGA (Australia)	July 23, 2026	Class-wide product information update for semaglutide, tirzepatide, liraglutide and dulaglutide; 36 Australian cases recorded [16][17]
Health Canada	June 23, 2026 (reported)	Reported to have updated Ozempic and Mounjaro monographs; the date comes from a plaintiff law firm’s press release, not a government page [18]

The Australian cases break down as 23 for semaglutide, 10 for tirzepatide, 3 for liraglutide and none for dulaglutide, though one semaglutide case involved prior dulaglutide use ^[16][17]. The TGA said it first identified the signal in July 2024 after a JAMA Ophthalmology study, and that its Advisory Committee on Medicines concluded in October 2025 that the evidence may support the signal for semaglutide but not for dulaglutide or tirzepatide. The TGA also stated that its updates should not be taken to imply a causal association, but reflect class-level awareness ^[16].

In the U.S., NAION claims have been consolidated in MDL 3163, created December 15, 2025 in the Eastern District of Pennsylvania before Judge Karen S. Marston, with 216 cases pending as of September 2026 and a Science Day hearing set for June 2, 2026 ^[13]. As with the gastrointestinal MDL, this is litigation, not a regulatory finding.

What has the FDA said about hair loss and altered skin sensation?

Hair loss (alopecia) and dysesthesia — altered skin sensation — are now listed among the most common adverse reactions on the Wegovy label ^[1]. They were added to the Rybelsus label’s clinical trials experience section on December 9, 2024, in the same approval that added the severe gastrointestinal warning to Rybelsus section 5.6 ^[11].

When the FDA approved Wegovy HD, the 7.2 mg higher dose, on March 19, 2026, its announcement said reports of altered skin sensation — described as sensitivity, pain or burning — were common, occurred more frequently at the higher dose than at lower doses, and generally resolved on their own or with dose reduction. The FDA stated it is conducting further investigation into this reaction ^[8]. That approval came just 54 days after filing, under the Commissioner’s National Priority Voucher pilot program ^[8].

What was the March 2026 warning letter to Novo Nordisk about?

On March 5, 2026, the FDA’s Center for Drug Evaluation and Research sent Novo Nordisk a warning letter citing serious violations of postmarketing adverse drug experience reporting rules, under section 505(k) of the FD&C Act and 21 CFR 314.80. The findings came from an inspection at the company’s headquarters between January 13 and February 7, 2025 ^[19].

The core problem, according to the FDA, was that Novo Nordisk’s written procedures allowed adverse event reports to be rejected or canceled when the reporter judged the event unrelated to the product. U.S. rules require serious and unexpected adverse events to be reported to the FDA within 15 calendar days regardless of whether anyone considers them causally related ^[19].

The letter’s examples include a liraglutide stroke case that was rejected because the patient said the stroke was unrelated to the drug; a semaglutide death report that lacked a valid patient identifier within 15 days; a semaglutide death report from a non-healthcare reporter that was closed without being reported; a semaglutide suicidal ideation report received December 16, 2024 whose medical review was not conducted until February 3, 2025; and a physician’s report of a semaglutide patient who was depressed and died by suicide, which the FDA said was not investigated or submitted ^[19][20]. The products covered were semaglutide, liraglutide, nedosiran sodium and estradiol ^[19].

The FDA judged the company’s response inadequate and gave it 15 business days to reply ^[19][20]. Novo Nordisk said on March 10, 2026 that the letter concerns regulatory compliance and makes no conclusion about the quality or safety of its medicines, and that it expects to resolve the matters ^[20].

Does the FDA review compounded semaglutide?

No. Compounded drugs are not FDA approved, and the agency does not review them for safety, effectiveness or quality before they are marketed. The FDA’s position is that compounded drugs should be used only when a patient’s medical needs cannot be met by an FDA-approved drug ^[7].

As of May 31, 2026, the FDA had received 990 adverse event reports associated with compounded semaglutide and more than 730 associated with compounded tirzepatide. The agency notes these are likely underreported, because state-licensed pharmacies that are not outsourcing facilities are not required to submit adverse events to the FDA ^[7].

The FDA has linked some adverse events, including hospitalizations, to dosing errors and to doses above the approved label or faster titration schedules ^[7]. Its handling advice for multi-dose vials includes discarding them within 28 days of first use even if medication remains, using a new sterile needle and syringe for each dose, and not using an injectable GLP-1 that arrives warm ^[7]. The agency has also stated that the salt forms semaglutide sodium and semaglutide acetate are different active ingredients with no lawful basis for compounding, that retatrutide and cagrilintide cannot be compounded under federal law, and that it has an import alert (66-80) on GLP-1 active pharmaceutical ingredients with quality concerns. It has also found fraudulent labels naming pharmacies that do not exist or were not involved ^[7].

How can I tell if my Ozempic pen is counterfeit?

The FDA has issued three counterfeit Ozempic alerts. On December 21, 2023, it flagged lot NAR0074, serial number 430834149057, after seizing thousands of units; testing found the needles, pen label, carton and patient information all counterfeit, and the sterility of the needles could not be confirmed ^[12]. On April 14, 2025, it flagged lot PAR0362 with serial numbers starting 51746517, after several hundred units were seized on April 9, 2025 ^[12].

On December 5, 2025, the FDA flagged counterfeit pens labeled with lot PAR1229 — which is also an authentic lot number. The tell is the placement of the EXP/LOT text: on the counterfeit pen it appears to the left of the expiration date and lot number, while on the authentic pen it appears above them. Novo Nordisk notified the FDA on November 18, 2025. Pens with lot PAR1229 received through the Novo Nordisk Patient Assistance Program are authentic and may be used ^[12].

The FDA’s standing advice is to obtain Ozempic only with a valid prescription through state-licensed pharmacies, to inspect the product before use, and for pharmacies to buy only from authorized distributors ^[12][7].

How do I report an Ozempic side effect to the FDA?

The route is the MedWatch program. Patients and healthcare professionals can complete and submit the MedWatch Online Voluntary Reporting Form, download a form or call 1-800-332-1088 to request one, or submit by fax to 1-800-FDA-0178 ^[10][12]. The Wegovy label lists the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch, and Novo Nordisk at 1-833-934-6891 ^[1].

The FDA encourages both patients and healthcare professionals to report side effects involving GLP-1 drugs ^[4][10]. For suspected counterfeit products, the FDA directs people to contact their local FDA consumer complaint coordinator, or to report suspected criminal activity ^[12].

What has the FDA not concluded?

Several open questions remain. The FDA has not determined whether the rodent thyroid C-cell tumors are relevant to humans — the boxed warning exists because that question is unanswered ^[1]. As of September 2026, no NAION warning has been added to the U.S. labels, unlike in Europe, the UK and Australia ^{[13][5][14][16]}. The FDA found no increased risk of suicidal thoughts or behavior and removed that warning in January 2026 ^[4]. Compounded semaglutide and tirzepatide are not reviewed by the FDA before marketing ^[7]. And the March 2026 warning letter to Novo Nordisk concerns reporting compliance, not the safety of the medicines themselves ^[20].

A timeline of the major U.S. label changes

Date	Change	Source
September 20, 2023	Ileus added to Ozempic labeling, based on voluntary reports; hypoglycemia language updated the same day	[9]
November 1, 2024	Ozempic supplement S-032 approved, adding the pulmonary aspiration warning	[2]
November 5, 2024	Anesthesia warning applied class-wide to semaglutide, liraglutide and tirzepatide products	[3]
November 27, 2024	Wegovy subsection 5.6, Severe Gastrointestinal Adverse Reactions, added to align with the class	[15]
December 9, 2024	Dysesthesia and alopecia added to Rybelsus section 6.1; severe GI warning added to 5.6	[11]
October 14, 2025	Ozempic S-035/S-037 add severe GI postmarketing statement; intestinal obstruction, severe constipation, acute kidney injury and headache added to 6.2	[6]
January 13, 2026	FDA requests removal of the suicidal behavior and ideation warning from Saxenda, Wegovy and Zepbound	[4]
March 19, 2026	Wegovy HD 7.2 mg approved; altered skin sensation noted as common, under FDA investigation	[8]

Sources

1. US Food and Drug Administration. Wegovy (semaglutide) prescribing information.
2. US Food and Drug Administration. Supplemental approval letter for Ozempic (semaglutide) injection, NDA 209637/S-032.
3. Medscape Medical News. FDA Updates GLP-1 Label With Pulmonary Aspiration Warning. November 6, 2024.
4. US Food and Drug Administration. FDA Requests Removal of Suicidal Behavior and Ideation Warning from GLP-1 RA Medications.
5. European Medicines Agency. PRAC concludes eye condition NAION is a very rare side effect of semaglutide medicines Ozempic, Rybelsus and Wegovy.
6. US Food and Drug Administration. Supplemental approval letter for Ozempic (semaglutide) injection, NDA 209637/S-035, S-037.
7. US Food and Drug Administration. FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight Loss.
8. US Food and Drug Administration. FDA Approves Fourth Product Under National Priority Voucher Program, Higher Dose Semaglutide.
9. HCPLive. FDA Adds New Warning for Ileus to Semaglutide (Ozempic) Label. September 28, 2023.
10. US Food and Drug Administration. Update on FDA’s ongoing evaluation of reports of suicidal thoughts or actions in patients taking a certain type of medicines approved for type 2 diabetes and obesity.
11. US Food and Drug Administration. Supplemental approval letter for Rybelsus (semaglutide) tablets, NDA 213051/S-020, S-021.
12. US Food and Drug Administration. FDA warns consumers not to use counterfeit Ozempic (semaglutide) found in U.S. drug supply chain.
13. MDL Update. Ozempic Vision Loss Lawsuit | MDL-3163. September 1, 2026.
14. GOV.UK. MHRA updates guidance for semaglutide prescribers and patients.
15. US Food and Drug Administration. Supplemental approval letter for Wegovy (semaglutide) injection, NDA 215256/S-015.
16. RACGP. TGA issues GLP-1 RA class-wide safety update. July 23, 2026.
17. The Guardian. Australian regulator warns of ‘rare but severe’ eye disorder linked to GLP-1 drugs like Ozempic. July 24, 2026.
18. PR Newswire. Parker Waichman Applauds Health Canada and Australia for Strengthening NAION Safety Guidance for Certain GLP-1 Medications. July 28, 2026.
19. US Food and Drug Administration. Warning letter to Novo Nordisk Inc. March 5, 2026.
20. Healio. FDA issues warning letter to Novo Nordisk for improper reporting of GLP-1 adverse events.