Regulators in both countries are asking for documentation that shows how an ingredient was made, not just what it is called.
In March 2024, Kobayashi Pharmaceutical recalled red yeast rice (beni-koji) supplements after reports of kidney injury. Kobayashi had notified the products under Japan's Foods with Function Claims (FFC) system, which does not involve government approval of safety or efficacy.¹
A survey conducted through the Japanese Society of Nephrology covered 189 cases and identified findings suggestive of proximal tubular injury. Separately, investigators identified puberulic acid, likely produced by a Penicillium mold that contaminated the red yeast rice raw material during cultivation. They confirmed its kidney toxicity in animal experiments.¹ The ingredient name on the package did not, and could not, reveal any of this.
My group's work with supplements for medical institutions in Japan dates to 2003. The lesson I draw for ingredient suppliers is that many decisions essential to product quality are made before an ingredient reaches the finished-product plant. For suppliers, the challenge is to make investments in quality visible to customers who otherwise struggle to distinguish one material from another.
For most tablet and capsule foods in Japan, GMP had long been a matter of government guidance and voluntary industry certification.² In August 2019, Japan's National Consumer Affairs Center reported that 42 of 100 selected tablet and capsule health foods did not disintegrate within Japanese Pharmacopoeia time limits. The center used these limits as a benchmark rather than as a legal requirement. The next day, the Japan Health and Nutrition Food Association made lot-by-lot disintegration testing mandatory at the plants it certifies under its GMP program.²,³ Binding requirements followed only after the red yeast rice crisis. For US readers weighing voluntary programs against regulation, that sequence is worth noting.
Japan responded in two steps. Since September 1, 2024, FFC notifiers must collect information on health harms that a physician has diagnosed as caused or suspected to be caused by their product. Notifiers must also promptly provide that information to the relevant local authority and the Consumer Affairs Agency (CAA) when there is a risk that harm may occur or spread.¹ With the end of a transition period, GMP became a requirement for FFCs in tablet, capsule, and similar forms made from defined raw materials and manufactured, processed, or imported on or after September 1, 2026. Those defined raw materials include certain natural-derived materials and chemically synthesized substances.¹
Three features are relevant to suppliers. GMP is defined from receipt of raw materials to shipment of finished products, and raw materials must meet the specifications the product requires. The notifier is responsible for compliance and must keep specification documents for the raw material containing the functional ingredient. If verifying the ingredient's origin matters for quality control, those documents must also state how and how often that origin is confirmed. CAA also calls on raw-material makers, importers, manufacturers, and notifiers to share GMP-based quality information along the supply chain.¹,⁴
Before the deadline, CAA figures as of the end of March 2026 showed that, of 234 facilities visited, 145 were broadly implementing GMP, 74 were building their systems, and 15 were outside scope.⁴ For suppliers selling into Japan, the practical consequence is the growing importance of documentation that supports customers' compliance.
On October 19, 2026, FDA issued final guidance covering the identity and safety sections of its earlier draft guidance on new dietary ingredient (NDI) notifications.⁵ As Nutritional Outlook has reported, it recommends documenting an ingredient's manufacturing process, specifications, supporting analytical methods, and impurities and contaminants.⁵,⁶ For suppliers, the premise matters more than any single recommendation: describing the manufacturing process, the guidance says, "helps FDA understand the identity of the NDI."⁵
The guidance is nonbinding and concerns ingredients that require a notification,⁵ and industry groups have pointed to questions it leaves open.⁶ It also lands in a market with layered rules for suppliers. Under FDA's dietary supplement current good manufacturing practice (cGMP) rule, a firm whose only customers further process its dietary ingredient into supplements is generally not subject to the rule, although FDA encourages such firms to follow applicable provisions. A supplier whose ingredient is simply packaged or labeled as a supplement, or sold directly to consumers, is subject to it.⁷ Dietary ingredient manufacturers generally remain subject to food cGMP and preventive-control requirements under 21 CFR Part 117.⁸ Supplement manufacturers, in turn, generally must test each dietary ingredient's identity, and may rely on supplier certificates of analysis for other specifications only with documented, periodically reconfirmed qualification.⁹
The two frameworks serve different purposes. One governs how covered products are made; the other explains the identity and safety information FDA recommends including in an NDI notification. Both underscore the importance of documenting the material and how it is made.
The guidance's discussion of fermentation-produced ingredients offers a practical parallel: it recommends describing safeguards against contamination of the production organism.⁵ Japan's experience illustrates why those safeguards matter. An ingredient's name alone cannot reveal a hazard introduced during production. For buyers, understanding the process helps identify which controls and supporting evidence to request.
Materials sharing an ingredient name can differ in assay results, particle size, conformity to applicable monographs, and contaminant profiles. Like a dish that depends on both the chef's choices and the kitchen's execution, a supplement reflects decisions made upstream. Unlike a dish, its quality cannot be judged by taste or appearance. In a historical example, researchers found detectable lead in 8 of 21 calcium carbonate supplements in 2000;¹⁰ a shared ingredient name did not establish equivalent contaminant profiles.
More recently, a 2023 analysis of 57 supplements purchased online and labeled as containing one of five selected performance-related ingredients found inaccurate ingredient labeling in 89% of the sample.¹¹ Such studies rarely show where in the supply chain a problem began. As Nutritional Outlook has reported, even passing an identity test does not guarantee that a material contains the compounds a buyer expects.¹²
This uncertainty creates the risk of a "market for lemons": when buyers cannot distinguish quality, higher-quality sellers may struggle to obtain a premium.¹³ The concern is familiar on the retail shelf, and in my view it applies one step upstream as well. When two ingredient offers carry the same name and similar certificates, price can become the deciding factor.
Part of the remedy is verifiable evidence of effective controls. In my view, suppliers that provide it as a matter of course will be better placed in both Japan and the United States. Five items are a practical starting point:
Where a supplier provides safety evidence, it should identify the material and conditions of use that the evidence supports.
These documents are useful only if customers can connect them to the material actually supplied and verify that the stated controls are being followed. None of this is a marketing claim. Much of it may already exist within a supplier's quality system. The next step is making it usable, and verifiable, for customers.
Japan's experience shows why effective manufacturing controls and verifiable information must travel together along the supply chain. Showing what cannot be seen, in words and in numbers, is the responsibility of every company that makes supplements and the ingredients that go into them.
About the author
Masaki Kaneko is CEO of KYB Group in Tokyo and a research fellow in the Faculty of Physical Education at Kokushikan University.
Disclosure
The author leads KYB Group, whose businesses include the manufacture and sale of supplements in Japan. No products marketed by the author’s company are discussed.
