Structure/Function Claims in Dietary Supplements: What Brands Must Know to Stay Compliant

Structure/function claims are among the most commercially important tools available to dietary supplement brands in the United States. They allow manufacturers to communicate meaningful health benefits to consumers — without the burden of a full drug approval process. However, these claims carry significant regulatory obligations that are frequently misunderstood or overlooked, exposing brands to FDA warning letters, FTC enforcement actions, and reputational risk.

What Is a Structure/Function Claim?

Under the Dietary Supplement Health and Education Act of 1994 (DSHEA), a structure/function claim describes the role of a nutrient or dietary ingredient in affecting the normal structure or function of the human body. Permissible examples include statements such as "Calcium builds strong bones" or "Antioxidants maintain cell integrity." These claims do not require FDA pre-approval. However, they must meet a specific set of statutory and regulatory requirements to be lawful.

The Four Core Compliance Requirements

To use a structure/function claim lawfully on a dietary supplement label or in advertising, brands must satisfy four requirements established under 21 CFR Part 101.93 and FDA guidance:

• The claim must be truthful and not misleading.

• The claim must be substantiated by competent and reliable scientific evidence at the time the claim is made.

• The label must carry the mandatory disclaimer: "This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease."

• The manufacturer must notify the FDA of the claim no later than 30 days after first marketing the product bearing the claim, as required under 21 CFR 101.93(a).

The Substantiation Standard: A Frequently Misunderstood Obligation

The substantiation requirement is the area where compliance failures most commonly occur. FDA and FTC both apply a "competent and reliable scientific evidence" standard, which generally means well-designed human clinical studies. Importantly, the evidence must be specific to the product formulation and the population for which the claim is made. Extrapolating data from studies conducted on a different extract composition, dose, or population introduces substantiation risk.

This is particularly relevant in the botanical and herbal ingredient space, where significant compositional variability exists across suppliers and extraction methods. A clinical study conducted on a standardized botanical extract cannot reliably substantiate a claim made for a non-standardized or differently processed version of the same plant material. Brands sourcing from multiple ingredient suppliers should evaluate substantiation on a supplier-specific and formulation-specific basis.

Common Violations That Trigger FDA and FTC Action

FDA warning letters and FTC enforcement actions related to structure/function claims most commonly involve one or more of the following violations:

• Claims that imply the product can diagnose, treat, cure, or prevent a disease — converting a permissible structure/function claim into an unlawful drug claim.

• Missing, incorrectly positioned, or insufficiently prominent FDA disclaimer language on the label.

• Use of disease terminology, including references to named conditions (e.g., diabetes, hypertension, Alzheimer's disease) in claims or product names.

• Failure to file the 30-day notification with FDA as required under 21 CFR 101.93(a).

• Testimonials or endorsements on product websites that imply disease treatment, even when the label itself is compliant.

Implications for Ingredient Suppliers and Finished Product Brands

For ingredient suppliers, the claims landscape affects B2B commercialization strategy. Suppliers who invest in clinical substantiation for their branded ingredients create a defensible platform that enables their customers — finished product brands — to make compliant and credible claims. This translates into measurable commercial value: documented clinical evidence supports higher price positioning, retailer acceptance, and consumer trust.

For finished product brands, pre-launch regulatory review of all label text, marketing copy, website content, and social media materials is essential. Reactive compliance — addressing violations after an FDA warning letter or FTC inquiry — is significantly more costly, both financially and reputationally, than proactive review.

How Blessed Harbor LLC Can Support Your Compliance Program

Blessed Harbor LLC provides structure/function claim development, substantiation brief preparation, label compliance audits, and 30-day FDA notification filing support for dietary supplement brands and ingredient suppliers. Our regulatory consulting practice is grounded in a working knowledge of FDA enforcement priorities and FTC advertising standards, helping clients build claims programs that are both commercially effective and legally defensible.

To discuss your specific claims compliance needs, please contact us via the Blessed Harbor LLC website.

References: 21 CFR Part 101.93; DSHEA 1994 (Public Law 103-417); FTC Dietary Supplements: An Advertising Guide for Industry (2001, updated 2022); FDA Guidance for Industry: Substantiation for Dietary Supplement Claims Made Under Section 403(r)(6) of the Federal Food, Drug, and Cosmetic Act (2008).