Under DSHEA and 21 CFR 101.93, dietary supplement labels may make structure/function claims: statements that describe the role of a nutrient or dietary ingredient in maintaining the normal structure or function of the human body. "Supports healthy immune function." "Promotes joint comfort." "Helps maintain healthy energy levels." These claims are permitted without pre-market FDA approval, provided they are truthful, not misleading, substantiated, and accompanied by the DSHEA disclaimer.
Disease claims — claims that a product diagnoses, cures, treats, mitigates, or prevents a specific disease or condition — are prohibited on dietary supplements. A product making disease claims is an unapproved drug, regardless of whether it's formulated and marketed as a supplement. Disease claims require the FDA approval process that supplements cannot obtain.
The compliance challenge is that the line between these two categories is not always obvious, and FDA's enforcement position is evaluated against the net impression of all the language, imagery, and context on the label and in advertising — not just the literal words of a single claim.
The FDA Framework: How the Line Is Drawn
FDA published a guidance document explaining how it distinguishes structure/function claims from disease claims. The guidance identifies the key factors:
Does the claim name a specific disease? "Helps with arthritis" is a disease claim. "Supports joint comfort" is a structure/function claim.
Does the claim name a symptom or characteristic associated with a specific disease? "Reduces blood pressure" is a disease claim even though it doesn't name hypertension — because consumers understand that blood pressure reduction relates to a disease. "Helps maintain blood pressure levels already within the normal range" is a structure/function claim because it's about maintaining normal function, not treating a disease state.
Does the claim refer to an abnormal condition? Claims about returning an abnormal condition to normal are disease claims. Claims about maintaining a normal condition are structure/function claims. "Helps normalize blood sugar" is a disease claim. "Helps maintain healthy blood sugar levels already within the normal range" may be a structure/function claim.
Does the product name, imagery, or advertising context create a disease claim impression? A product called "Cholesterol Away" carrying the claim "supports cardiovascular health" is making a disease claim through its name. A product whose advertising is placed exclusively in healthcare settings for patients with a specific condition is marketing a disease treatment regardless of label language.
The Most Commonly Crossed Lines
These are the specific claim patterns that generate the most FDA warning letters to supplement brands.
Cardiovascular claims
Disease claims: "lowers cholesterol," "reduces LDL," "decreases blood pressure," "reduces cardiovascular risk," "prevents heart disease," "reduces the risk of heart attack"
Structure/function claims: "supports healthy cholesterol levels already within the normal range," "promotes cardiovascular health," "supports healthy circulation," "helps maintain healthy blood lipid levels already in the normal range"
The "already within the normal range" qualifier does a lot of regulatory work in supplement claims. It signals that the claim is about maintenance, not treatment — the product supports a system that's functioning normally, not a system that's diseased. But FDA evaluates whether this qualifier is credible given the advertising context. A product marketed to people with elevated cholesterol, with "already within the normal range" in the fine print, may be read as a disease claim regardless of the qualifier.
Blood sugar and diabetes claims
Disease claims: "controls blood sugar," "lowers blood glucose," "helps manage diabetes," "reduces insulin resistance," "prevents type 2 diabetes"
Structure/function claims: "helps maintain healthy blood sugar levels already within the normal range," "supports healthy glucose metabolism," "promotes healthy insulin sensitivity"
Blood sugar claims are among the most heavily scrutinized in the supplement space. Products with ingredients commonly associated with diabetes management — berberine, chromium, bitter melon — are regularly flagged for disease claims even when the claims use compliant structure/function language, because FDA and FTC evaluate the totality of the marketing — including where the product is sold, who the target audience is, and whether the advertising implies disease treatment.
Inflammation and immune claims
Disease claims: "reduces inflammation," "treats inflammatory conditions," "reduces arthritis symptoms," "prevents autoimmune flare-ups," "cures infections"
Structure/function claims: "supports a healthy inflammatory response," "promotes immune function," "helps the body maintain its normal immune defenses," "supports healthy joints"
"Reduces inflammation" is a disease claim — inflammation is a symptom associated with multiple diseases. "Supports a healthy inflammatory response" is a structure/function claim — it describes the body's normal process. The wording difference is small; the regulatory difference is significant.
Mental health and cognitive claims
Disease claims: "treats depression," "reduces anxiety," "prevents Alzheimer's disease," "treats ADHD," "helps with PTSD"
Structure/function claims: "supports a calm mood," "promotes mental clarity," "helps maintain healthy cognitive function," "supports memory and focus"
Mental health claims are an area of increasing FDA and FTC enforcement attention. Products marketed for stress, mood, focus, and sleep often cross the disease claim line — particularly when the advertising imagery or audience targeting implies disease treatment.
The Marketing Channel Problem
The most important thing to understand about structure/function claim enforcement: FDA and FTC evaluate the entire marketing ecosystem, not just the label.
A label with compliant structure/function claims, paired with a website that makes disease claims about the same product, is making disease claims. A social media post by a brand-paid influencer who says "this product cured my anxiety" creates disease claim exposure for the brand, even if the post doesn't appear on the label. An Amazon listing description that describes the product as "anti-inflammatory" is a disease claim.
FDA routinely cites marketing copy, website language, and social media content alongside label language in warning letters. The compliance obligation runs across every channel where the brand or its affiliates communicate about the product.
Substantiation: The Other Half of the Obligation
A structure/function claim that is truthful and compliant with the disease-claim boundary still requires substantiation. Under DSHEA, structure/function claims must be substantiated by competent and reliable scientific evidence. FDA has interpreted this in alignment with FTC's standard: the level of substantiation should be appropriate to the specificity of the claim.
A claim that a specific ingredient "supports healthy immune function" requires evidence that the ingredient actually has an effect on immune function in humans, at the doses used in the product. Mechanistic data (it works in a test tube) and animal studies generally are not sufficient alone. Human clinical trials are generally required for disease-adjacent claims. Expert opinions and ingredient GRAS status are not substantiation for efficacy claims.
Substantiation documentation should be maintained for every structure/function claim — not just available in principle, but documented and linked to the claim in a compliance record. When a warning letter arrives asking for substantiation, the documentation needs to exist already.
The DSHEA Disclaimer: Non-Negotiable
Every structure/function claim on a dietary supplement label or in advertising requires the exact DSHEA 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."
Under 21 CFR 101.93, this language must be:
Exact — no paraphrasing, no abbreviation
Placed prominently — on the label adjacent to the claim, not buried in fine print at the bottom of a back panel
Present with every structure/function claim — including in advertising and on websites, not just on the physical label
Brands that modify the disclaimer ("This statement has not been evaluated by the FDA") or omit it from one channel while including it on another are in violation.
Building a Compliant Claims Process
The brands that stay out of FDA enforcement are the ones who've built claim review into how marketing operates — not as a final review gate, but as a stage in the content creation process.
Every proposed claim should be evaluated before it's used: does it describe normal structure/function or does it imply disease treatment? Is it substantiated? Does it require a specific accompanying disclosure? The answers should be documented, linked to the claim, and accessible if enforcement ever comes.
Claims approved for one channel should not automatically be used in others without review. A claim that works on a label may create disease claim implications in a different advertising context. Each channel and campaign should be treated as a new claim review trigger.
Structure/Function Claims Can Work — When They're Reviewed Properly
The supplement marketing landscape is not without compliant options. Hundreds of ingredients have well-documented effects on normal body structure and function that can be communicated compliantly. The constraint is precision: the claims have to describe those effects accurately, within the regulatory framework, with the substantiation to back them up.
Truli's AI compliance platform evaluates structure/function claims against the disease claim boundary — flagging language that crosses the line and suggesting compliant alternatives. The Claims Hub documents the regulatory basis and substantiation notes for every claim, with full review history. Social monitoring catches disease claims in influencer and affiliate content before FDA does. Book a demo to see how Truli manages structure/function claim compliance across your brand.
