Every supplement label walks a line that federal law drew decades ago and enforces continuously: a dietary supplement can describe how an ingredient supports the normal structure or function of the body, but it cannot claim to diagnose, treat, cure, mitigate, or prevent a disease. That second category is reserved for drugs, which go through a completely different approval process. Understanding where that line sits — and how easily marketing language slides across it — matters as much as any formulation decision, because a claims problem can freeze inventory, trigger a warning letter, or force a label reprint just as fast as a manufacturing defect.
A structure/function claim describes a nutrient's role in maintaining normal health. "Calcium supports bone strength," "Supports healthy immune function," and "Helps maintain normal energy metabolism" are all standard examples. These claims are allowed under the Dietary Supplement Health and Education Act because they describe normal physiology, not the treatment of a medical condition. A disease claim, by contrast, states or implies that a product affects a disease or its symptoms — "Relieves arthritis pain," "Lowers cholesterol," "Treats anxiety," or "Reduces symptoms of menopause" all fall into that category, even though some of these phrasings sound like ordinary marketing language.
The test the FDA applies is not just the literal wording but the overall impression a reasonable consumer would take away. That's where many brands get into trouble. A label might use careful structure/function language — "supports healthy blood sugar levels already within a normal range" — while the website, social media captions, or influencer scripts talk about "reversing prediabetes" or "managing your A1C." Regulators and retailers increasingly look at the whole marketing ecosystem, not just the printed panel, when deciding whether a claim is a disguised disease claim. A legally sound label can still get a brand in trouble if the rest of its content doesn't match.
The disclaimer is not optional boilerplate
Any product carrying a structure/function claim must display a specific disclaimer, usually near the Supplement Facts panel: that the statement has not been evaluated by the FDA and that the product is not intended to diagnose, treat, cure, or prevent any disease. This isn't decorative legal language — it's a required part of the claim itself. Brands that make a structure/function claim without this disclaimer, or bury it in text too small to be noticed, are out of compliance regardless of how carefully the claim itself was worded.
There's also a notification requirement that catches many first-time brand owners off guard: a company making a structure/function claim is required to notify the FDA within 30 days of the product's first appearance on the market with that claim, and must have substantiation on file that the claim is truthful and not misleading. This isn't a pre-approval process — the FDA doesn't sign off in advance — but the notification and the underlying substantiation file need to exist, and both should be handled with input from regulatory counsel rather than left to guesswork.
Where the line gets blurry
A few patterns account for most of the claims problems that show up in real product lines. Naming a disease directly is the most obvious trap — mentioning "diabetes," "depression," "arthritis," or "cancer" anywhere in the claim almost always converts it into a disease claim, even if the rest of the sentence is softened. Implied disease claims are subtler: describing symptoms strongly associated with a specific disease, referencing lab values patients associate with a diagnosis, or using before/after imagery that mimics a clinical outcome can all create the same legal problem without using a disease name at all. Comparative language that positions a supplement as an alternative to a prescription drug — "instead of statins" or "a natural alternative to antidepressants" — is another frequent offender, because it implies the product treats the same condition the drug treats.
Customer testimonials deserve particular caution. A brand can be held responsible for a disease claim made by a customer in a testimonial if the brand selects, edits, or amplifies that testimonial in its own marketing. "This product cured my insomnia" repeated in an ad becomes the brand's claim, not just the customer's opinion.
There is a narrow, well-defined exception for classical nutrient deficiency diseases — a claim like "vitamin C prevents scurvy" is permitted because it's a factual statement about a recognized deficiency disease, and the label must state how common that deficiency is in the United States. This exception is specific and doesn't extend to chronic diseases like heart disease or diabetes, so it's not a workaround for the general rule.
For brand owners working with a contract manufacturer, it's worth remembering that the manufacturer can flag obvious claims risks during label proofing, but the legal responsibility for what the label and marketing say rests with the brand bringing the product to market. Building a claims review step into the launch process — ideally with someone who understands both the FDA framework and how it's actually enforced — is far cheaper than discovering a problem after a print run, a retail listing, or an ad campaign is already live.
