What the FDA Says About GLP-1 Safety: Every Warning on the Label

If you want to know what regulators actually believe about GLP-1 drug safety, there is a better source than any news article: the FDA-approved prescribing information. It is public, it is free, and it is updated every time the agency changes its mind.

This article walks through what the FDA currently says about semaglutide and the wider GLP-1 class, where those positions came from, and, just as usefully, what the FDA has decided not to say. It is a reference guide, not medical advice. Nothing here should be used to start, stop or adjust a medicine. That is a conversation for your own healthcare provider.

How do FDA drug warnings work?

Three layers matter, in descending order of seriousness:

1. Boxed warning. The strongest warning the FDA uses, reserved for risks that can cause serious harm or death. It sits in a black box at the very top of the label.
2. Warnings and Precautions. Risks the FDA believes the evidence supports, usually with monitoring or management advice.
3. Postmarketing Experience. Events reported voluntarily after approval. The label itself says these come from “a population of uncertain size,” which means they are signals, not proof that the drug caused the event.

There is also a Recent Major Changes box near the top of the label that lists exactly which sections changed and in what month. It is the fastest way to see what a regulator has done lately.

What is the boxed warning on semaglutide?

Thyroid C-cell tumors. The current Wegovy label states that “in rodents, semaglutide causes thyroid C-cell tumors at clinically relevant exposures,” and that “it is unknown whether WEGOVY causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans as the human relevance of semaglutide-induced rodent thyroid C-cell tumors has not been determined” [1].

The practical consequence is a contraindication. Semaglutide “is contraindicated in patients with a personal or family history of MTC or in patients with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2)” [1]. This warning has been on the label since the original Ozempic approval in December 2017.

Two points get lost in headlines. First, the rodent finding is real and has not been resolved either way in humans. Second, the contraindication is specific: it names medullary thyroid carcinoma and MEN 2, not thyroid conditions in general.

What is in the Warnings and Precautions section?

For Wegovy, as of the current label, the list runs [1]:

• Acute pancreatitis. Observed with GLP-1 receptor agonists. Discontinue if pancreatitis is suspected.
• Acute gallbladder disease. Occurred in clinical trials; gallbladder studies and follow-up are indicated if gallstones are suspected.
• Hypoglycemia. Risk rises when used with insulin or an insulin secretagogue.
• Acute kidney injury due to volume depletion. Monitor kidney function in patients with reactions that could cause dehydration.
• Severe gastrointestinal adverse reactions. The label says Wegovy “is not recommended in patients with severe gastroparesis.”
• Hypersensitivity reactions. Anaphylaxis and angioedema reported after marketing.
• Diabetic retinopathy complications in patients with type 2 diabetes. Patients with a history of diabetic retinopathy should be monitored.
• Heart rate increase. Monitor at regular intervals.
• Pulmonary aspiration during general anesthesia or deep sedation.

The Ozempic label is similar, with the obvious difference that it covers diabetes rather than weight management populations.

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

This is the most practically important warning for many patients, and it is recent.

GLP-1 drugs slow how quickly the stomach empties. That is part of how they work. The problem is that people can still have food in their stomach at the time of a procedure even after following normal fasting instructions, which raises the risk of stomach contents entering the lungs under sedation.

The FDA acted on September 6, 2024, formally notifying manufacturers under section 505(o)(4) of the Federal Food, Drug, and Cosmetic Act of “new safety information” about “the serious risk of pulmonary aspiration for patients undergoing elective surgeries or procedures requiring general anesthesia or deep sedation” [2]. Revised labels across the class, covering semaglutide, tirzepatide and liraglutide products, were approved on November 1, 2024 [2][3].

The new label text describes “rare postmarketing reports of pulmonary aspiration in patients receiving GLP-1 receptor agonists undergoing elective surgeries or procedures requiring general anesthesia or deep sedation who had residual gastric contents despite reported adherence to preoperative fasting recommendations” [3].

The patient counseling instruction is simple: tell healthcare providers before any planned surgery or procedure that you are taking a GLP-1 medicine. That includes dental procedures under sedation, colonoscopies and outpatient surgeries. The label does not tell you to stop the drug, and neither will this article; the timing decision belongs to your surgical and prescribing teams.

What does the FDA say about gastroparesis, ileus and bowel obstruction?

This area has been built up gradually rather than in one announcement.

• September 2023: the FDA had ileus, meaning a stalled bowel, added to the Ozempic Postmarketing Experience section after reviewing adverse event reports [9].
• November 27, 2024: a new Warnings and Precautions subsection on severe gastrointestinal adverse reactions was added to Wegovy to align with other GLP-1 labels [15].
• October 14, 2025: the FDA approved further revisions to both Ozempic and Wegovy. Section 5 was updated to state that “severe gastrointestinal adverse reactions have also been reported postmarketing with GLP-1 receptor agonists,” and the Postmarketing Experience section added “intestinal obstruction, severe constipation including fecal impaction” and “acute kidney injury.” A separate supplement added “headache” [6].

The current Wegovy label also carries a use restriction rather than a hard contraindication: Wegovy “is not recommended in patients with severe gastroparesis” [1].

The most common side effects remain the ordinary gastrointestinal ones: nausea, vomiting, diarrhea, constipation and abdominal pain.

Federal lawsuits alleging gastroparesis, ileus and intestinal obstruction from GLP-1 drugs have been consolidated in the Eastern District of Pennsylvania as MDL 3094, with roughly 4,000 cases pending as of September 2026. Litigation is not a regulatory finding, and the existence of a lawsuit does not establish that a drug caused an injury.

Did the FDA find a link to suicidal thoughts?

No, and it reversed course publicly.

The story began in July 2023, when the FDA opened an investigation after postmarketing reports of suicidal ideation and behavior in people taking GLP-1 drugs. Its January 30, 2024 Drug Safety Communication reported that a preliminary review of trial and postmarketing data did not find evidence that these medicines cause suicidal thoughts or actions, while acknowledging real uncertainty because individual trials contained few cases [10].

The agency then did the larger analysis. On January 13, 2026 it published a Drug Safety Communication requesting that manufacturers remove the suicidal ideation and behavior language from the labels of Saxenda (liraglutide), Wegovy (semaglutide) and Zepbound (tirzepatide) [4]. The evidence behind it:

• A meta-analysis of 91 placebo-controlled GLP-1 trials covering 107,910 patients (60,338 on a GLP-1, 47,572 on placebo). Results “did not show an increased risk for SI/B or for other relevant psychiatric adverse events such as anxiety, depression, irritability, or psychosis” [4].
• A retrospective cohort study using the FDA Sentinel System comparing 2,243,138 people starting a GLP-1 or an SGLT2 inhibitor between October 2015 and September 2023. After adjusting for baseline differences, the FDA “did not find an increased risk of intentional self-harm in GLP-1 RA users compared to SGLT2i users,” including among people with both type 2 diabetes and obesity [4].
• A review of published observational and pooled studies, which the agency concluded “does not support a causal relationship” [4].

The current Wegovy label confirms the change, listing “Suicidal Behavior and Ideation (5.10) … (Removed) 01/2026” in its Recent Major Changes box [1].

The FDA still advises telling a healthcare professional about new or worsening depression, suicidal thoughts or unusual mood changes, and points to the 988 Suicide and Crisis Lifeline [4].

Can semaglutide cause sudden vision loss?

This is the one place where the FDA and European regulators visibly disagree, and it is worth understanding precisely.

The condition is non-arteritic anterior ischemic optic neuropathy, or NAION. It happens when blood flow to the front of the optic nerve drops, causing sudden vision loss that is usually in one eye at a time and often permanent.

Europe acted first. On June 6, 2025, after reviewing non-clinical studies, clinical trials, post-marketing surveillance and published literature, the EMA’s Pharmacovigilance Risk Assessment Committee concluded that NAION is a very rare side effect of semaglutide, meaning it may affect up to 1 in 10,000 people, and recommended adding it to the product information for Ozempic, Rybelsus and Wegovy. The committee noted that “results from several large epidemiological studies suggest that exposure to semaglutide in adults with type 2 diabetes is associated with an approximately two-fold increase in the risk of developing NAION” [5].

The UK followed on February 5, 2026, updating its product information for prescribers and patients [14].

Australia followed in 2026. On July 23, 2026 the Therapeutic Goods Administration issued a class-wide medicines safety update and added NAION to the Product Information for every GLP-1 receptor agonist marketed in Australia, including Ozempic and Wegovy (semaglutide), Mounjaro (tirzepatide), Saxenda (liraglutide) and Trulicity (dulaglutide). The TGA acted after 36 reported Australian cases, and the semaglutide text now says that “some epidemiological studies indicate an increased risk of NAION during treatment with semaglutide” [16][17].

Canada also moved. Health Canada is reported to have updated the Ozempic and Mounjaro product monographs on June 23, 2026 to direct clinicians to evaluate sudden vision loss urgently and stop treatment if NAION is confirmed. That date comes from a law firm announcement rather than a Health Canada page, so treat it as reported but not independently confirmed [18].

The United States has not. The FDA-approved Wegovy prescribing information does not list NAION in its Warnings and Precautions [1]. What began as a US-versus-Europe split is now the United States on one side and the EU, UK, Australia and Canada on the other. That absence is a central allegation in the federal GLP-1 vision loss litigation, consolidated in December 2025 as MDL 3163 before Judge Karen S. Marston in the Eastern District of Pennsylvania [13].

To be clear about what “very rare” means in European labeling terms: up to 1 in 10,000 people. A doubling of a very small baseline risk is still a very small risk. But if this concerns you, sudden vision changes in one eye are a reason to seek urgent medical attention regardless of what medicine you take, and it is a fair topic to raise with an eye doctor.

What about hair loss and skin sensitivity?

Hair loss. Alopecia was added to the clinical trials experience section of the Rybelsus label in December 2024 [11]. The FDA has been tracking reports of alopecia with semaglutide and tirzepatide since at least early 2024.

Altered skin sensation. This is newer. When the FDA approved Wegovy HD 7.2 mg on March 19, 2026, its own announcement said that “reports of altered skin sensation (described as sensitivity, pain, or burning) were common, occurred more frequently at the higher Wegovy dosage than lower dosages, and generally resolved on its own (or with dose reduction),” and that “the FDA is currently conducting further investigations regarding this drug reaction” [8]. That is unusually direct language in an approval announcement and worth watching.

Has the FDA criticized how Novo Nordisk reports side effects?

Yes, and it is a recent and specific finding. On March 5, 2026 the FDA’s Center for Drug Evaluation and Research issued a warning letter (MARCS-CMS 717576) to Novo Nordisk Inc. in Plainsboro, New Jersey, citing “serious violations” of postmarketing adverse drug experience (PADE) reporting requirements under section 505(k) of the Federal Food, Drug, and Cosmetic Act and 21 CFR 314.80 [19].

The letter followed an FDA inspection conducted between January 13 and February 7, 2025, and covered products whose active ingredients include semaglutide, liraglutide, nedosiran sodium and estradiol. The FDA cited a failure to develop written procedures ensuring that the company and its contractor complied with PADE regulations, and reported that some serious adverse events, including three patient deaths, were not submitted by the legal deadline [19][20].

Novo Nordisk said on March 10, 2026 that it takes PADE reporting requirements seriously and expected to resolve the matters raised [20].

Why this belongs in a safety article: the label only reflects what the agency knows, and the agency largely learns from reports. A finding that reports were late does not by itself change any warning on any label, and the FDA has not said it does. But it is a reason to read “the label does not mention X” as a statement about the current evidence record rather than a guarantee.

What does the FDA say about compounded GLP-1 drugs?

Something different, and blunter: it does not vouch for them at all.

“Compounded drugs are not FDA approved. This means the agency does not review compounded drugs for safety, effectiveness or quality before they are marketed” [7].

The agency’s running safety concerns with compounded GLP-1 products include:

• Adverse events. As of May 31, 2026: 990 reports for compounded semaglutide and more than 730 for compounded tirzepatide. FDA notes state-licensed pharmacies that are not outsourcing facilities are not required to report, “so it is likely that adverse events from compounded versions of these drugs are underreported” [7].
• Dosing errors. Hospitalizations have followed patients or clinicians miscalculating doses drawn from vials, and prescribing above approved label doses or titrating faster than the label allows [7].
• Multi-dose vials. FDA recommends discarding a vial 28 days after first use even if medicine remains, and says not to follow compounder instructions allowing longer use. Use a new sterile needle and syringe every time [7].
• Shipping temperature. Do not use any injectable GLP-1 that arrives warm or with insufficient ice [7].
• Salt forms. Semaglutide sodium and semaglutide acetate are different active ingredients, and FDA is “not aware of any lawful basis for their use in compounding” [7].
• Fraudulent labels. Some products carry the names of pharmacies that do not exist, or of real pharmacies that did not make them [7].
• Retatrutide and cagrilintide. Investigational, not components of any approved drug, and not lawfully compoundable [7].

How do I spot counterfeit Ozempic?

The FDA has issued three counterfeit alerts, and each one names a specific lot [12]:

Date	Lot	Detail
December 21, 2023	NAR0074	Thousands of units seized; the pen label, carton, patient information and the needles were counterfeit, raising infection risk
April 14, 2025	PAR0362	Several hundred units; serial numbers beginning 51746517; seized April 9, 2025
December 5, 2025	PAR1229	On counterfeit pens the EXP/LOT text appears to the left of the expiration date and lot number instead of above them

For the 2025 lot, FDA added an important caveat: patients who received Ozempic 1 mg with lot number PAR1229 through the Novo Nordisk Patient Assistance Program “may continue using the product as it is authentic Ozempic” [12].

The agency’s general advice is to buy only through state-licensed pharmacies with a valid prescription, and to inspect the product before use.

How do I report a side effect?

Through MedWatch, the FDA’s adverse event reporting program. You can [7]:

• Complete the MedWatch Online Voluntary Reporting Form at accessdata.fda.gov
• Call 1-800-332-1088 to request a paper form, then mail or fax it to 1-800-FDA-0178

Both patients and healthcare professionals can report. These reports are how signals like ileus and NAION surface in the first place, so reporting genuinely matters.

What the FDA has not said

It is worth naming the gaps, because a lot of online content fills them with speculation:

• The FDA has not concluded that semaglutide causes thyroid cancer in humans. The boxed warning describes a rodent finding of unknown human relevance [1].
• The FDA has not added a NAION warning to US labels as of September 14, 2026, despite European, UK, Australian and Canadian action [1][5][14][16].
• The FDA has not found an increased risk of suicidal thoughts or behavior, and removed that warning in January 2026 [4].
• The FDA does not review compounded semaglutide before it is sold, so no FDA safety statement covers those products [7].

If you want to check any of this yourself, open the current prescribing information for the specific product you take, read the Recent Major Changes box, then read Sections 4, 5 and 6. It takes about ten minutes and it is the most reliable information available anywhere.

And whatever you find there, talk it through with a healthcare provider who knows your history before acting on it.

Sources

1. Wegovy (semaglutide) injection and tablets prescribing information, FDA
2. FDA supplement approval letter, NDA 209637/S-032 (pulmonary aspiration safety labeling change)
3. FDA Updates GLP-1 Label With Pulmonary Aspiration Warning, Medscape
4. FDA Requests Removal of Suicidal Behavior and Ideation Warning from GLP-1 RA Medications
5. PRAC concludes eye condition NAION is a very rare side effect of semaglutide medicines, EMA
6. FDA supplement approval letter, NDA 209637/S-035, S-037
7. FDA’s Concerns with Unapproved GLP-1 Drugs Used for Weight Loss
8. FDA Approves Fourth Product Under National Priority Voucher Program, Higher Dose Semaglutide
9. FDA Adds New Warning for Ileus to Semaglutide (Ozempic) Label, HCPLive
10. Update on FDA’s ongoing evaluation of reports of suicidal thoughts or actions, FDA
11. FDA supplement approval letter, NDA 213051/S-020, S-021
12. FDA warns consumers not to use counterfeit Ozempic found in U.S. drug supply chain
13. MDL 3163: GLP-1 NAION Products Liability Litigation, MDL Update
14. MHRA updates guidance for semaglutide prescribers and patients
15. FDA supplement approval letter, NDA 215256/S-015
16. TGA issues GLP-1 RA class-wide safety update, RACGP newsGP
17. Australian regulator TGA warns of ‘rare but severe’ eye disorder linked to GLP-1 drugs like Ozempic, The Guardian
18. Parker Waichman on Health Canada and TGA NAION guidance (plaintiff-side announcement; used only for the June 23, 2026 Health Canada date, which is unconfirmed against a government source)
19. FDA Warning Letter to Novo Nordisk Inc., MARCS-CMS 717576, March 5, 2026
20. FDA issues warning letter to Novo Nordisk for improper reporting of GLP-1 adverse events, Healio