Hundreds of thousands of Americans stand to soon lose their access to cheaper weight-loss drugs, with a federal crackdown on copycat versions threatening to disrupt treatment and raise costs. The Food and Drug Administration has ordered producers and sellers of the less expensive products to wind down operations in coming weeks now that it has declared there are no longer shortages of the Wegovy and Zepbound.

Produced through a process of mixing drug ingredients known as compounding, the copycat medications had spawned a booming multibillion-dollar industry. Patients turned to compounding because their health insurance would not pay for the brand-name drugs and they could buy the compounded versions for less than $200 a month in some cases.

Eli Lilly and Novo Nordisk now offer the brand-name drugs for $500 a month in most cases to patients who pay with their own money instead of going through insurance. Until recently, patients sometimes had to pay more than $1,300 a month.

The FDA ordered compounding for versions of Eli Lilly’s Zepbound to end last month. Small compounders have until Tuesday to stop selling versions of Novo Nordisk’s Wegovy; large compounders have until May 22.

It is not clear how the FDA will enforce these deadlines.

The compounding industry has been waging a public relations campaign and fighting in court to reverse the orders, but has been unsuccessful so far. A trade group for large compounders estimates that millions of patients are getting the weight-loss drugs through compounding, which, if accurate, would rival sales of the brand-name products.

Compounding obesity drugs has generated huge business for telehealth companies and medical spas that connect patients with prescribers. One of the largest providers, the telemedicine company Hims & Hers, reported more than$225 million in revenue from a category of weight-loss drug offerings.