MHRA updated semaglutide product information over a very rare eye condition
On 5 February the MHRA updated product information for prescribers and patients regarding the risk of non-arteritic anterior ischaemic optic neuropathy, or NAION, in people taking semaglutide. NAION involves reduced blood flow to the front of the optic nerve and typically causes sudden, painless loss of vision in one eye. The MHRA said studies suggest the association is very rare, meaning it may affect up to 1 in 10,000 people taking the drug.
What this actually means
Very rare means very rare. Up to 1 in 10,000 is the regulator's own framing, and for almost everyone this will not change the decision to take it or not.
What it does change is what you watch for. Sudden painless loss of vision in one eye is not something to wait out. Get seen the same day. That is worth knowing whether or not you are on any medication, because the causes that are not this one are also urgent.
The reason a change this small gets a formal update is worth understanding too. It is the system working: a signal appeared in monitoring data, the regulator assessed it, and the label now says so. Unlicensed compounds bought online have no equivalent process, so a signal like this would simply never surface.
What this is. A dated, sourced note on something that changed. Peptide Register is an independent reference: it sells nothing, carries no advertising, and takes no money from any company selling any compound it covers. This is not medical advice. If a change affects a medicine you are prescribed, speak to your doctor or pharmacist rather than acting on something you read here.