On April 13, 2023, the Federal Trade Commission (FTC) sent approximately 670 notices of penalty offenses to various companies involved in the marketing of OTC drugs, homeopathic products, dietary supplements, and functional foods, placing them on notice that they could incur significant civil penalties if they fail to adequately substantiate product claims. The cover letters suggest that the recipients consult FTC staff’s recently issued Health Products Compliance Guidance. The letter to the recipient companies also provides a copy of a previously approved notice of penalty offenses regarding the use of endorsement and testimonials.