WHO issues a global statement on semaglutide and NAION

The World Health Organization published a medical product alert on June 27, 2025, warning health-care professionals and drug regulators about the risk of non-arteritic anterior ischemic optic neuropathy, known as NAION, in people using semaglutide medicines — Ozempic, Rybelsus and Wegovy ^[1].

The alert echoes a decision by the European Medicines Agency. The EMA has recommended that the product information for these three medicines be updated to list NAION as a side effect with a frequency classified as "very rare" ^[1].

What NAION is

NAION is a leading cause of vision loss in adults and the second most common optic neuropathy after glaucoma, according to WHO ^[1]. It usually appears as sudden, painless vision loss in one eye, along with swelling of the optic disc ^[1]. WHO states that the vision loss is generally irreversible and that there is currently no effective treatment ^[1].

The numbers behind the "very rare" label

The EMA's Pharmacovigilance Risk Assessment Committee, or PRAC, reviewed all available data on NAION and semaglutide. That included non-clinical studies, clinical trials, post-marketing surveillance and published medical literature ^[1]. PRAC concluded that NAION is a very rare side effect of semaglutide, potentially affecting up to 1 in 10,000 users ^[1].

EMA's guidance is specific about what to do if symptoms appear: patients who experience a sudden loss of vision or rapidly worsening eyesight during semaglutide treatment should contact their doctor without delay ^[1]. If NAION is confirmed, EMA says treatment with semaglutide should be stopped ^[1].

WHO's own expert body reached a similar conclusion separately. At its May 2025 meeting, the WHO Advisory Committee on Safety of Medicinal Products decided that the Risk Management Plan for semaglutide should be revised to include NAION as a potential risk, along with any additional safety monitoring activities that are required ^[1].

WHO said it issued the alert because of how widely semaglutide is used around the world and because NAION is serious ^[1]. The agency also noted that it has received individual case safety reports of NAION following semaglutide use from multiple countries through VigiBase, the global database of reported adverse events for medicines ^[1].

The WHO alert cites two pieces of underlying work: the June 6, 2025 EMA announcement on the PRAC conclusion, and a Danish–Norwegian cohort study on semaglutide use and NAION risk published in Diabetes, Obesity and Metabolism ^[1]. The specific risk estimates from that cohort study were not detailed in the alert ^[1].

Why it matters for patients

Semaglutide is the active ingredient in medicines used for type 2 diabetes and obesity ^[1]. Ozempic and Rybelsus are approved for type 2 diabetes; Wegovy is the weight-management version. All three are covered by the WHO alert ^[1].

The practical upshot is about recognition and speed. Because there is no effective treatment for NAION and the vision loss is usually permanent ^[1], the regulatory response centers on telling patients what symptoms to report and telling clinicians when to stop the drug ^[1]. Sudden vision loss in one eye, or eyesight that gets worse quickly, is the pattern regulators are asking people on semaglutide to flag to a doctor without delay ^[1].

It also helps to keep the frequency in view. "Very rare" in European labeling terms means up to 1 in 10,000 people treated ^[1]. That is a small number, but WHO's point is that with very large numbers of users globally, even a very rare event produces real cases ^[1].

One thing the WHO alert does not do is change any prescribing rules in the United States. WHO alerts are addressed to health-care professionals and national regulatory authorities, not to a single country's labeling ^[1]. Whether US labels for Ozempic, Rybelsus and Wegovy carry the same NAION language has not been reported here, and no US Food and Drug Administration action on this issue is described in the alert ^[1].

Also not addressed: whether the risk differs by dose, by how long someone has been taking semaglutide, by which brand is used, or whether other GLP-1 medicines such as tirzepatide (Mounjaro, Zepbound) carry a similar signal. The alert is limited to semaglutide products ^[1].

What happens next

The EMA recommendation, announced June 6, 2025, calls for the product information for Ozempic, Rybelsus and Wegovy to be updated to include NAION ^[1]. WHO's advisory committee has asked for semaglutide's Risk Management Plan to be revised to add NAION as a potential risk, which can include extra safety monitoring ^[1]. A date for those updates reaching patients and prescribers in each country has not been disclosed ^[1].