FAT jab users are scrambling to buy Mounjaro before price hikes of more than 50 per cent.
Pharmacies reported an influx of phone calls at the weekend as anxious patients tried to stock up.
A typical monthly prescription for weight loss injection Mounjaro — medical name tirzepatide — could rise from less than £200 to more than £300 from the start of September.
Dr Leyla Hannbeck, of the Independent Pharmacies Association, said: “Some patients have asked to buy in bulk, which is not possible or safe.
“There are alternatives and patients should speak to their local pharmacist.”
More than a million people in the UK are estimated to be buying fat jab injections privately.
Some 625,000 could now switch to rival drug Wegovy, after its manufacturer Novo Nordisk confirmed on Friday that it will not raise its prices .
Dr Sophie Dix, from online pharmacy MedExpress, said: “Our patients are fearful of being unable to afford treatment.”
And Sandeep Dhami, from MW Phillips Chemists in the West Midlands, said: “Patients are going to pharmacies angry and upset at the price hike.
“Those on the highest doses, who will face the highest price hike , are particularly concerned.”
Experts called for calm and warned users not to be tempted by sellers on social media .
Abdal Alvi, at Simple Online Pharmacy, said: “Cheap is not cheap when it comes to health.”
Boots chemist has said it will review its weight loss services in light of the change.
