At a Glance:
- The FTC has issued notification letters to Amazon and Walmart regarding potentially unqualified “Made in USA” claims from third party sellers on their platforms
- FDA is now treating certain third party customer reviews as product “labeling,” expanding the scope of what companies are responsible for on their websites
- Analytical testing methods are facing deeper scrutiny, with FDA questioning whether common techniques like NIR and FTIR spectroscopy meet “scientifically valid” standards
- Weight loss supplements remain one of five product categories FDA watches most closely due to higher incidence of adulteration
Understanding enforcement trends has become essential knowledge for regulatory affairs professionals, brand owners, and supplement executives navigating an increasingly complex compliance landscape. The Food and Drug Administration continues to refine its approach to dietary supplement oversight, and the warning letters issued throughout 2025 reveal patterns that every industry stakeholder should study carefully. From expanded definitions of what constitutes product labeling to deeper examination of laboratory testing methods, the regulatory environment demands more attention to detail than ever before.
For manufacturers and brands producing liquid formulations and other delivery formats, the stakes are particularly high. Teams at Superior Supplement Manufacturing Inc. have noted increased inquiries from brand partners seeking guidance on compliance documentation and label review processes. This heightened awareness reflects an industry that recognizes FDA enforcement is evolving in ways that require proactive preparation rather than reactive scrambling.
“The brands that stay out of trouble are the ones paying attention to warning letter trends even when those letters are not addressed to them,” says Jake Hyten, CEO of Superior Supplement Manufacturing. “Every warning letter FDA publishes is essentially a free lesson in what not to do. Smart operators study them closely.”
The Expanding Definition of Product Labeling
One of the more surprising developments in recent enforcement involves FDA treating third party customer reviews as product labeling under certain circumstances. A warning letter issued to a kratom company cited customer reviews displayed on the company’s website as evidence of improper disease claims. This interpretation caught many in the industry off guard, as product review widgets have traditionally been considered user generated content outside the company’s direct control.
The nuance matters significantly. According to FDA’s guidance on labeling, companies may be held responsible for claims that appear on their websites if those claims are curated, endorsed, or given special prominence. Reviews displayed in featured banners or testimonial sections carry different risk than those appearing in standard third party review widgets. However, the kratom warning letter appeared to blur these lines, suggesting FDA may take an aggressive stance with product categories it views as problematic.
Phil Hixon, VP of Sales at Superior Supplement Mfg., emphasizes the importance of reviewing all website content through a compliance lens. “We tell our brand partners to audit everything on their sites regularly. That includes review sections, blog posts, social media feeds that display on the site, and any third party content that could be interpreted as making claims about the product. If it appears on your domain, you need to assume FDA might hold you accountable for it.”
Made in USA Claims Under the Microscope
The Federal Trade Commission has entered the supplement enforcement conversation with notification letters sent to major platforms including Amazon and Walmart. These letters address potentially unqualified “Made in USA” claims made by third party sellers, signaling that origin claims will face increased scrutiny across the industry.
The issue extends beyond explicit “Made in USA” text. Similar phrases like “Manufactured in USA,” “American Made,” and “Handcrafted in USA” fall under the same regulatory umbrella. Even the use of American flag imagery without proper qualification could trigger enforcement action. For supplement brands selling through online marketplaces, the time to review all product listings for compliant origin language is now.
FTC requirements for unqualified “Made in USA” claims are stringent. Products must be “all or virtually all” made in the United States, meaning all significant parts and processing must be of U.S. origin. Many supplement brands that source ingredients internationally but encapsulate or bottle domestically may not qualify for unqualified origin claims. Qualified claims that accurately describe the domestic and foreign content offer a compliant alternative for brands that want to highlight their American manufacturing operations.
Analytical Testing Methods Face Deeper Scrutiny
Beyond labeling and claims, FDA inspectors are examining the scientific validity of analytical methods used by manufacturers to verify ingredient identity and product specifications. The agency has taken particular note of the widespread use of scanning spectroscopy techniques like Near Infrared (NIR) and Fourier Transform Infrared (FTIR) spectroscopy for identification testing.
While these methods offer advantages in speed and cost compared to traditional wet chemistry approaches, FDA has questioned whether they meet the “scientifically valid” standard required by GMP regulations in certain applications. Warning letters have cited inadequate reference standard libraries and insufficient method validation as specific concerns. Manufacturers relying heavily on spectroscopic identification should evaluate whether their methods have been properly validated for the specific ingredients they are testing.
“Testing is one of those areas where manufacturers sometimes try to cut corners without realizing the regulatory risk,” notes Hyten. “A certificate of analysis is only as good as the methods behind it. When FDA starts asking questions about how you validated your NIR library, you need to have solid documentation ready. Otherwise, a routine inspection can turn into a warning letter very quickly.”
High Risk Product Categories
Weight loss supplements continue to attract disproportionate FDA attention due to the category’s history of adulteration with undeclared pharmaceutical ingredients. Products making weight management claims, particularly those positioned as natural alternatives to prescription medications, face elevated scrutiny. The recent explosion of GLP 1 adjacent supplements has only increased regulatory focus on this space.
Other high risk categories include sexual enhancement products, bodybuilding supplements, and any products making claims related to diabetes or blood sugar management. Brands operating in these categories should implement enhanced quality controls and consider third party testing specifically designed to screen for common adulterants.
Ophthalmic products represent another enforcement priority. FDA treats any product formulated for application to the eyes as subject to Over the Counter drug monograph requirements, regardless of how the product is marketed. Warning letters sent to major retailers in recent years underscore that this category has no tolerance for supplement style compliance approaches.
Preparing for the Enforcement Environment Ahead
The patterns emerging from 2025 warning letters suggest FDA is deepening rather than broadening its enforcement approach. Rather than targeting more companies, the agency appears focused on examining compliance with greater technical detail. This means manufacturers and brands must go beyond surface level GMP adherence and ensure their systems can withstand rigorous inspection of underlying documentation, validation records, and scientific justification.
“Compliance is not a destination. It is an ongoing process,” says Hixon. “The companies that view regulatory requirements as a living system that needs constant attention are the ones that sleep well at night. The ones that check a box and forget about it are the ones who end up in warning letter databases.”
For supplement brands at every stage of growth, studying FDA enforcement trends provides invaluable guidance on where to focus compliance resources. The lessons embedded in warning letters issued to others can help prevent costly mistakes and position brands for sustainable success in an industry where quality and regulatory adherence increasingly determine market viability.
