Warning Letter
A public FDA enforcement notice - more serious than a 483 - that stays online permanently.
An FDA Warning Letter is a formal enforcement notice issued when the agency believes a company has significantly violated regulations - often after an unsatisfactory response to a Form 483. Unlike a 483, Warning Letters are public and permanent: your competitors, retailers, and class-action attorneys can find them with a search.
Ignoring one can escalate to injunction, product seizure, or worse. Most supplement Warning Letters involve drug claims, unsubstantiated label claims, or GMP failures.
Related terms
Guides that cover Warning Letter
The "Oh Crap, The FDA Is Calling" Guide to 21 CFR 111 Testing Requirements
Getting StartedSupplement Testing for New Brands: What to Do First (Before You Waste Money)
Getting StartedHow to Read a Certificate of Analysis: What the Numbers Actually Mean
ComplianceProp 65 Supplement Testing: Don't Wait for the Lawsuit Letter
Selling OnlineHow to Use Your Test Results in Marketing (Without Getting an FDA Letter)
FDA & GMPSupplement Finished Product Testing: The GMP Release Checklist
Compliance5 FDA Supplement Regulations You're Probably Violating Right Now
Free Resources21 CFR 111 GMP Compliance Checklist — Free PDF Download
FDA & GMPDSHEA Explained for Supplement Brands
FDA & GMPFDA Warning Letters for Supplements -- Testing Violations
FDA & GMPForm 483 Response Guide for Supplement Companies
Amazon & MarketplaceGMP Certificate for Amazon -- Do You Need One?
ComplianceSupplement Label Claim Substantiation — Testing Every Word on Your Bottle
ComplianceStructure/Function Claims Testing Requirements
Getting StartedThird-Party Supplement Testing: Why It's Non-Negotiable
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