FDA Warns Signature Formulations Over Serious GMP Violations

In July 2025, the U.S. Food and Drug Administration inspected Signature Formulations, LLC, a U.S. contract manufacturer of OTC drug products, and identified major Good Manufacturing Practice violations. Similar deficiencies had already been highlighted in 2018.

The FDA found that several products were manufactured on shared equipment without proper physical separation, creating a high risk of cross-contamination. Potent drug ingredients were processed on the same equipment later used for children’s toothpaste and mouthwash. Concerns about contamination with exogenous hormones led to a voluntary recall of certain batches.

The company argued that it did not manufacture drugs, but the FDA clarified that the products fall under drug regulations according to the Federal Food, Drug, and Cosmetic Act (FD&C Act) and must meet GMP standards.

Inspectors also cited inadequate cleaning validation, lack of risk assessments, and major quality system failures, including incomplete product testing, missing raw material identity checks, poor deviation investigations, and the absence of a robust stability program.

04-03-2026