Companies · · 2 min read
Editor: Bohdan S.
FDA orders eye-risk warning on Lilly and Novo weight-loss drugs
The US regulator wants every GLP-1 drug, including Wegovy and Zepbound, to flag a rare optic nerve condition. The risk looks small, but it touches the industry's biggest sellers.
The short answer
The US Food and Drug Administration said on Monday that all GLP-1 drugs, including Novo Nordisk's Ozempic and Wegovy and Eli Lilly's Mounjaro and Zepbound, must warn of a possible higher risk of NAION, a rare eye condition that can cause permanent vision loss. The Financial Times (FT) also reported the move. It is a label update, not a sales restriction.
What happened
On Monday the FDA told patients and doctors that GLP-1 medicines may raise the risk of non-arteritic anterior ischemic optic neuropathy, or NAION, a rare problem in which reduced blood flow to the optic nerve causes sudden, painless loss of sight in one eye, sometimes for good. The agency is making the holders of all 12 approved products in the class, from older diabetes drugs to Lilly's new oral pill Foundayo, add the risk to the warnings and precautions section of their labels. The Financial Times (FT) reported the order as a blindness risk warning for weight-loss drug makers. Both companies told NBC News that patient safety is their top priority.
What it means
The decision ends a review that began after a July 2024 study in JAMA Ophthalmology linked semaglutide, the ingredient in Ozempic and Wegovy, to more NAION cases. The FDA said that study had limitations, so it looked at a much wider set of evidence: adverse event reports, animal studies, outside research and its own analysis of clinical trials.
The numbers point to a real but small signal. Pooling 126 trials with more than 78,000 GLP-1 users, the agency found 6.4 cases per 100,000 patient-years on the drugs against 3.8 for people on comparison treatments. Only 15 probable cases turned up in total. A separate FDA study of real-world diabetes patients found no significant extra risk compared with SGLT-2 drugs such as Jardiance, but did find one compared with DPP-4 drugs such as Januvia. The agency could not find a biological reason for the link, and it noted that common NAION risk factors, like diabetes, high blood pressure and sleep apnea, are also common among people who take these medicines.
Europe moved first. Last year the European Medicines Agency's safety committee said semaglutide may, in very rare cases, cause NAION, estimating it could affect up to 1 in 10,000 people using it for at least a year. The US step now applies the warning to the whole drug class, not just one molecule.
Why this matters for investors is scale. According to BioSpace, Lilly's Mounjaro and Zepbound brought in a combined $36.51 billion in 2025, and Novo's semaglutide family earned $36.19 billion. Analysts at BMO said in a note that they see limited risk to the two companies because the condition is rare and the FDA chose a label warning rather than limiting approved uses.
The bull case
For Lilly and Novo, the uncertainty that hung over the eye question is now settled in a fairly mild way. The warning sits in the precautions section, not a boxed warning, and approved uses are untouched. The measured gap between users and non-users is a few cases per 100,000 patient-years, and every GLP-1 now carries the same language, so no single brand is singled out against its rivals.
The bear case
A formal US warning gives patients and doctors one more reason for caution, which could weigh on new prescriptions at the margin, especially among people taking the drugs for weight loss rather than diabetes. The FDA could not explain how the drugs might cause the condition, which leaves room for more research and further scrutiny. Damage to sight is permanent in some cases, so the headline risk is hard to dismiss.
Why it matters
For investors
Shares of the two leading obesity drug makers, Eli Lilly and Novo Nordisk, are the most directly exposed, since their biggest-selling brands are all covered. BMO analysts framed the change as a manageable label update rather than a commercial setback.
The wider context
GLP-1 drugs now rank among the drug industry's top sellers, so their safety record matters for anyone whose savings or pension funds hold large pharmaceutical stocks. For patients, the FDA advises contacting a doctor right away about sudden vision changes.
Market impact
| Asset (ticker) | Possible move | Timeframe | Why |
|---|---|---|---|
| Eli Lilly (LLY) | ↔ Unclear | Short term | BMO sees limited sales risk because the warning is a label update and the condition is rare. |
| Novo Nordisk (NVO) | ↔ Unclear | Short term | Semaglutide already carries a similar warning in Europe, so the US step formalizes a known signal. |
The FinPrism newsroom's view of how these figures could move, as of . It is general news commentary, not a recommendation to buy, sell or hold anything.
Frequently asked questions
What is NAION and how is it linked to Ozempic?
NAION is a rare condition in which reduced blood flow to the front of the optic nerve causes sudden, painless vision loss in one eye, which can be permanent. The FDA found a potential increased risk in people taking GLP-1 drugs such as Ozempic, but it could not identify how the drugs might cause it.
Which weight-loss drugs need the new FDA warning?
The order covers every approved GLP-1 medicine, 12 products in all. They include Novo Nordisk's Ozempic, Wegovy and Rybelsus, Eli Lilly's Mounjaro, Zepbound and Foundayo, and older diabetes drugs such as Victoza, Saxenda and Trulicity. Makers must add the risk to the warnings and precautions part of the label.
How big is the eye risk from GLP-1 drugs?
It looks small in absolute terms. The FDA's pooled analysis of 126 clinical trials found 6.4 NAION cases per 100,000 patient-years among GLP-1 users, compared with 3.8 among people on placebo or other diabetes drugs. Europe's regulator estimated semaglutide may affect up to 1 in 10,000 long-term users.
Sources: US Food and Drug Administration, Financial Times, CNN (Reuters), BioSpace, NBC News
How this was made: written with AI assistance from the sources listed above, following our editorial standards.
