European regulator labels NAION a very rare side effect of semaglutide
European and UK regulators now list NAION, a rare cause of sudden vision loss, as a very rare semaglutide side effect, with about one extra case per 10,000 person-years of treatment.
The European Medicines Agency's safety committee has concluded that a serious eye condition is a very rare side effect of semaglutide, the active substance in Ozempic, Rybelsus and Wegovy. The committee recommended adding the condition, non-arteritic anterior ischemic optic neuropathy (NAION), to the product information for all three medicines [1].
The conclusion, announced on 6 June 2025, followed a review of non-clinical studies, clinical trials, post-marketing surveillance and medical literature [1]. The Pharmacovigilance Risk Assessment Committee (PRAC) classified NAION as "very rare," meaning it may affect up to 1 in 10,000 people taking semaglutide [1]. The UK's Medicines and Healthcare products Regulatory Agency (MHRA) repeated that figure in a safety update published on 5 February 2026 [2].
Large epidemiological studies suggest that adults with type 2 diabetes who take semaglutide have roughly twice the relative risk of developing NAION compared with people not taking the medicine, according to the EMA. That corresponds to about one additional case per 10,000 person-years of treatment, where one person-year means one person taking the drug for one year [1]. Data from clinical trials also point to a slightly higher risk in people taking semaglutide compared with people taking a placebo [1].
Background rates of NAION vary widely. In people with type 2 diabetes, published estimates range from 11.4 to 82 cases per 100,000 person-years, the MHRA said. In the general population, estimates run from 7.73 to 11.35 per 100,000 person-years among people 40 and older, 10.2 per 100,000 among those 50 and older, and 14.79 per 100,000 among those 60 and older [2].
NAION typically causes sudden, painless vision loss, usually in one eye at a time, often described as blurring or cloudiness [2]. Risk factors listed by the MHRA include type 2 diabetes, smoking, high blood pressure and high cholesterol [2]. Semaglutide is sold as Ozempic and Rybelsus for type 2 diabetes and as Wegovy for weight management and cardiovascular risk reduction [2].
The UK committee that reviewed the evidence, the Pharmacovigilance Expert Advisory Group of the Commission on Human Medicines, noted "conflicting evidence in the literature" but agreed with the recommendation to update UK product information [2]. The MHRA said the UK has received three spontaneous reports suggestive of NAION with semaglutide from the drug's first authorization in 2018 through 1 August 2025. Over roughly the past five years, an estimated 10.2 million packs of semaglutide were dispensed there [2]. A report to a regulator does not mean the medicine caused the problem, the agency said [2].
Other GLP-1 medicines were not part of the review, and the MHRA said it is reviewing evidence for an association with other GLP-1 agonists [2]. Both regulators say treatment with semaglutide should be stopped if NAION is confirmed [1][2]. The MHRA advises that patients reporting a sudden loss of vision, including partial loss, be urgently referred for examination by an ophthalmologist [2].
Why it matters for patients
The absolute risk is small. The EMA and MHRA both describe NAION as very rare, affecting up to 1 in 10,000 people taking semaglutide, with the studies in type 2 diabetes pointing to about one extra case per 10,000 treated per year [1][2].
NAION is a condition that can permanently affect sight, and it usually strikes one eye at a time as sudden, painless vision loss [2]. Because the symptoms can be mistaken for other eye problems, the MHRA tells clinicians to ask patients with sudden vision loss whether they use semaglutide, noting that privately prescribed semaglutide may not appear in a patient's medical history [2].
The Food and Drug Administration's position on NAION and semaglutide has not been reported in either regulator's announcement, and no US labeling change has been disclosed. The two reviews also do not say how often NAION in semaglutide users affected one eye versus both, or how vision recovered afterward.
What happens next
The EMA said PRAC's recommendations go to the Committee for Medicinal Products for Human Use, which will adopt the agency's opinion [1]. The EMA revised its announcement on 13 June 2025 to delete a reference to the European Commission issuing a legally binding decision on the procedure [1].
The MHRA said the Summary of Product Characteristics and Patient Information Leaflet for semaglutide products in the UK will be updated in the coming months to describe the NAION risk [2]. As of that 5 February 2026 update, its review of other GLP-1 agonists was still ongoing [2].
Sources
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