The FDA has doubled down on its decision to remove Eli Lilly’s tirzepatide from its list of products that are in shortage. The agency’s move means that compounding pharmacies will have to halt production of their knockoff versions of diabetes drug Mounjaro and obesity treatment Zepbound.

During the shortage, compounders have suddenly thrived, flooding the market with their lower-cost copycats to meet the booming demand for Lilly and Novo Nordisk’s weight loss treatment

Meanwhile, outsourcing facilities that have been endorsed through the FDA’s 503B registration process will have until March 19 to produce tirzepatide treatments.

“Our determination is based on our conclusions that supply meets or exceeds current demand, and that, based on our best judgment looking at the available information with its limitations, supply will also meet or exceed projected demand,” Patrizia Cavazzoni, M.D., director of the FDA’s Center for Drug Evaluation and Research, wrote in a letter published on the agency’s website.