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FDA Warning Letter

Regulatory

Also known as: Warning letter, FDA enforcement, WL

A formal FDA communication notifying a company of significant regulatory violations.

What It Means

An FDA Warning Letter is an official communication identifying significant violations of FDA regulations and requesting corrective action. For supplements, common triggers include: cGMP violations (Part 111), unapproved drug claims, adulterated products, and failure to report adverse events. Warning Letters are public record and indicate serious regulatory issues. Companies must respond within 15 working days with a corrective action plan.

What It Is Not

A Warning Letter is not a fine, recall, or injunction — it is a notification demanding corrective action. However, failure to adequately respond can lead to stronger enforcement actions. Warning Letters are a lagging indicator — violations existed before the letter. A clean Warning Letter history does not mean no violations exist, only that FDA has not yet identified and formally communicated them.

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