Millions of Americans must decide whether to give up on new weight loss drugs or move to more expensive branded versions, after the US medical regulator in effect called time on the production of cheaper replicas.

While Novo Nordisk and Eli Lilly were unable to keep up with demand for their new blockbusters Wegovy and Zepbound, an unusually large market for “compounded” versions developed after the FDA medical regulator declared official shortages in 2022.

Compounded drugs are custom made by pharmacies using the active ingredients of patented drugs. In the past two years, patients have been able to buy compounded versions of Novo ingredient semaglutide and Lilly’s tirzepatide for as little as $199 a month. The US list price, charged to people without insurance, ranges from $1,000 to $1,300 for the branded drugs.