FDA warns ProRx over sterility problems in compounded tirzepatide and semaglutide

The FDA issued a warning letter dated April 7, 2026, to ProRx LLC, a 503B outsourcing facility in Exton, Pennsylvania, saying its compounded drug products failed to meet the conditions that let such facilities operate outside standard drug approval rules, and citing serious sterility deficiencies that "put patients at risk" ^[1].

The letter, from the agency's Center for Drug Evaluation and Research, follows an inspection of the facility from September 9 to 19, 2025. The FDA issued a Form 483 at the end of that inspection on September 19, 2025, and an amended Form 483 on October 10, 2025. The agency said it reviewed ProRx's October 24, 2025 response and received additional correspondence on February 13, 2026 ^[1]. ProRx registered as a 503B outsourcing facility on April 27, 2022, and most recently on February 20, 2026 ^[1].

Before the warning letter, on October 15, 2025, the company recalled Lot PRORX08062025-3 of Tirzepatide Injection 27 mg/3 mL, 3 mL in multidose vials, along with various lots of Semaglutide Injection multidose vials in multiple strengths that were still within their expiration dates. The recall was due to a lack of sterility assurance ^[1].

According to the letter, the facility compounded tirzepatide products using tirzepatide bulk drug substance. The FDA said those products are not eligible for 503B exemptions because tirzepatide does not appear on the agency's 503B bulks list and was not used to compound a drug on the drug shortage list at the time of compounding, distribution and dispensing ^[1]. The letter also said some products lacked required label information, including the statement "Not for Resale," and that at least one product did not list the drug's established name. The FDA further said the company's adverse event reporting procedures were inadequate — they lacked an adequate definition of a "serious" adverse event and did not require a follow-up report within 15 calendar days of new information ^[1].

On sterility, the FDA listed several findings: products were approved and distributed despite colony-forming unit recoveries found on ISO 5 operator gloves and settle plates; an operator blocked first air by placing gloved hands or forearms over an open tray of stoppers; stoppers moved from an ISO 7 area into an ISO 5 laminar airflow workstation without surface disinfection; a non-sterilized scissors was used inside the ISO 5 processing area; and a buffer room floor showed visible discoloration of unknown cause. The FDA also cited manufacturing practice failures, including incomplete investigations of batch discrepancies and inadequate environmental monitoring ^[1].

The agency has taken similar action against other 503B compounders. In April 2025, it warned Empower Pharma, a Houston facility that Eli Lilly has sued over compounded tirzepatide, over sterility and labeling problems ^[2]. That report noted that the FDA's finding that the tirzepatide shortage had ended set a March 19 deadline for many 503B facilities to stop compounding tirzepatide ^[2].

Why it matters for patients

Compounded drugs are not FDA-approved. The FDA letter states that ProRx has no approved applications on file for the drugs it compounds, and that its products do not qualify for the exemptions that allow 503B facilities to make bulk batches without going through the approval process ^[1]. The sterility findings matter because injectable drugs that may be contaminated can cause infections.

The recall covers one named lot of compounded tirzepatide and "various lots" of compounded semaglutide multidose vials; the letter does not list the semaglutide lot numbers ^[1]. Whether ProRx is still shipping compounded GLP-1 products, and what the company has told its customers, has not been reported. People who received compounded tirzepatide or semaglutide and are unsure of its origin can ask the pharmacy that dispensed it whether ProRx was the source.

For comparison, semaglutide is sold as the FDA-approved brands Ozempic, Wegovy and Rybelsus, and tirzepatide as Mounjaro and Zepbound; compounded versions of these molecules are not FDA-approved ^[1].

What happens next

The warning letter is dated April 7, 2026, and was issued by the FDA's Center for Drug Evaluation and Research ^[1]. The letter does not state a deadline for ProRx's response, and no further FDA enforcement action has been reported. The FDA said it intends to issue more specific manufacturing regulations for outsourcing facilities and has issued a revised draft guidance on current good manufacturing practice for 503B facilities ^[1].