How a Structure/Function Claim Gets FDA Review

A structure/function claim is the type of statement most commonly found on dietary supplement labels — phrases such as "supports healthy immune function" or "helps maintain bone density." These statements describe a role a nutrient or ingredient is said to play in the normal structure or function of the human body. They are legally distinct from disease claims, which assert that a product diagnoses, treats, cures, or prevents a specific illness, and that distinction is the axis around which the entire regulatory process turns.

The pathway through which such claims reach a consumer's label is governed by the Dietary Supplement Health and Education Act of 1994 (DSHEA) and the regulations the Food and Drug Administration has issued under it. Understanding that pathway — what it requires, what it checks, and what it does not check — is the subject of this piece. The process involves the manufacturer, the FDA, and a required label disclosure, but it does not involve pre-market approval of the kind applied to pharmaceutical drugs.

The Notification Pathway: What Happens Before a Claim Appears on a Label

Under 21 CFR Part 101.93, a dietary supplement manufacturer that wishes to use a structure/function claim must notify the FDA no later than 30 days after the product bearing that claim first enters commerce. This is a post-market notification, not a pre-market approval. The product may legally be sold before the FDA has reviewed or responded to the notification.

The notification itself must include the text of the claim, the name and address of the manufacturer or distributor, and the name of the dietary ingredient to which the claim applies. The FDA then has the opportunity to evaluate whether the claim crosses the line from a permissible structure/function statement into a prohibited disease claim. If the agency determines that a submitted claim does constitute a disease claim in disguise — for example, by naming a recognized disease or referencing a clinical sign strongly associated with one — it can issue a warning letter or take enforcement action.

Crucially, the notification process does not include a review of the underlying scientific evidence. The FDA does not evaluate, during the 30-day window, whether the claim is actually substantiated by competent and reliable scientific evidence. That substantiation requirement exists independently under FTC jurisdiction for advertising and under FDA regulations for labeling, but no agency formally approves the evidence package before the product ships. The burden of substantiation rests with the manufacturer.

As part of how supplements are regulated by the FDA, this notification model is one of the clearest illustrations of the difference between the supplement and drug frameworks: drugs require demonstrated efficacy before market entry; supplements do not.

The Regulatory Bodies, Label Requirements, and Manufacturer Obligations Involved

The Food and Drug Administration (FDA) receives the 30-day notification and holds authority to challenge claims it classifies as disease claims. It also enforces Good Manufacturing Practice (GMP) regulations under 21 CFR Part 111, which govern how a supplement is produced — though GMP compliance speaks to manufacturing quality rather than to the validity of a structure/function claim. The FDA's post-market surveillance system, which tracks consumer and healthcare provider reports of adverse events, can also surface safety concerns that ultimately affect how a product is labeled or whether it remains on the market. That adverse event reporting system is a separate but parallel mechanism; how FDA adverse event reports shape supplement safety describes how that data pipeline functions.

The Federal Trade Commission (FTC) shares oversight responsibility for supplement claims, specifically in advertising. While the FDA governs the product label, the FTC governs claims made in commercials, online advertisements, and promotional materials. Both agencies apply a "competent and reliable scientific evidence" standard, but they operate through different enforcement mechanisms. The FTC does not receive the 30-day notification; it monitors advertising independently.

The manufacturer or distributor is the party legally responsible for ensuring that a structure/function claim is truthful, not misleading, and substantiated. The manufacturer must also ensure that the label bears a mandatory disclaimer — prescribed verbatim by regulation — stating that the claim has not been evaluated by the FDA and that the product is not intended to diagnose, treat, cure, or prevent any disease. This disclaimer must appear prominently and conspicuously on the label, and its absence is itself a regulatory violation.

Third-party certification bodies (such as USP, NSF International, or Informed Sport) play no formal role in the structure/function claim review process. Their programs address ingredient identity, potency, and purity — not the legal or scientific validity of label claims. The distinction between what a third-party seal covers and what FDA oversight covers is explored in detail when examining how USP verification differs from FDA approval.

Where the Process Breaks Down: Ambiguity, Enforcement Gaps, and the Disease-Claim Boundary

The most persistent friction in the structure/function claim system is the boundary between a permissible structure/function statement and a prohibited disease claim. The FDA has published guidance outlining factors it considers — including whether the claim names a specific disease, references a sign or symptom that is characteristic of a disease, or implies a disease relationship through consumer perception. But the line is not always bright. A claim like "supports healthy blood sugar levels already within the normal range" is generally treated differently from "lowers blood sugar," yet both concern the same physiological variable. Manufacturers and the FDA have disagreed repeatedly about where specific claims fall.

The 30-day notification window creates a second area of friction: the FDA does not have the resources or legal authority under DSHEA to pre-screen every claim before it reaches consumers. Thousands of notifications are filed annually. The agency's response capacity is limited, which means that claims that might ultimately be found impermissible can remain on shelves for extended periods before enforcement action occurs.

Substantiation is a third gap. While both the FDA and FTC require that structure/function claims be backed by competent and reliable scientific evidence, neither agency reviews that evidence at the time of notification or product launch. A manufacturer may hold a thin file of preliminary studies, or studies conducted in animal models, and still legally file a notification. The quality and quantity of supporting evidence are not assessed unless and until an enforcement action is initiated — at which point the manufacturer must produce its substantiation file.

Finally, the mandatory disclaimer — though required — does not appear to meaningfully alter consumer interpretation in all cases. Research has shown that consumers sometimes read a structure/function claim and infer a therapeutic benefit regardless of the disclaimer's presence. This is a documented limitation of the current labeling framework, not a failure of any individual product.

What the Label and the Notification Record Actually Show — and What They Do Not

A dietary supplement label that carries a structure/function claim and the required disclaimer reflects, at minimum, that the manufacturer filed a notification with the FDA within the required 30-day window. It does not reflect that the FDA reviewed and approved the claim, that the underlying science was evaluated by any regulatory body, or that the product was tested for the accuracy of its Supplement Facts panel before reaching market.

The Supplement Facts panel itself — the standardized label box listing serving size, ingredient amounts, and percent daily values where applicable — is a separate regulatory requirement from the structure/function claim. Its format is mandated by 21 CFR Part 101, but the accuracy of the values it contains is not verified by the FDA prior to sale. A label may declare a specific milligram quantity of an ingredient; whether the product actually contains that amount is a manufacturing quality question governed by GMP regulations, not by the claim notification process.

Third-party testing programs address this gap by independently verifying that a product's contents match its label. Those programs — and what a Certificate of Analysis from such testing actually documents — are a distinct layer of the quality record. The notification filed with the FDA under 21 CFR Part 101.93 is a public record accessible through the FDA's database, but it contains only the claim text and basic manufacturer information, not any scientific dossier.

For consumers and researchers examining a supplement's regulatory record, the presence of a structure/function claim on a label is therefore evidence of a notification, not evidence of efficacy, safety review, or manufacturing accuracy. Each of those dimensions has its own documentation trail, and none of them is fully captured by the claim or its disclaimer alone.

The structure/function claim system reflects a deliberate legislative choice made in 1994 to treat dietary supplements as a category distinct from drugs — one where market entry does not require demonstrated efficacy and where the primary accountability mechanism is post-market enforcement rather than pre-market review. The framework's strengths and limitations both flow directly from that foundational design decision.

Note: This explains how supplements work. This statement has not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease, and it is not a substitute for advice from a physician, pharmacist, or registered dietitian.