A structure/function claim describes how a nutrient or dietary ingredient affects the body's normal structure or function, such as "calcium builds strong bones." Making one legally requires three things at once: the mandatory FDA disclaimer on the label, a notification filed with FDA promptly after first marketing the product, and documented substantiation proving the claim is truthful and not misleading.
TL;DR:
- Filing a proper notification within 30 days of first marketing is crucial, and any changes to the claim after submission can render it unnotified.
- Building a comprehensive evidence dossier that includes human clinical trials and explains how each supports the claim is essential for FDA scrutiny.
- Marketing claims must align precisely with notified label claims, as exaggerations in advertising can trigger separate FTC enforcement actions.
- Key compliance failures include late or missing notifications, disclaimers placed improperly, and language that implies disease treatment rather than supporting normal functions.
- Maintaining updated documentation and integrating evidence-based review early in product development minimizes risk of enforcement and legal issues.
Table of Contents
- What Qualifies as a Structure/Function Claim
- Notification and Disclaimer Requirements Under 403(r)(6)
- Building Substantiation That Holds Up Under Scrutiny
- Advertising vs. Labeling: Where FTC Enforcement Enters
- A Step-by-Step Compliance Checklist for Manufacturers
- Where Compliance Breaks Down in Practice
- How NutraSmarts Supports Substantiation and Label Compliance
- A Realistic Roadmap for Claims Compliance
- Turn Your Claim Dossier Into a Working Label
- Sources
What Qualifies as a Structure/Function Claim
The Dietary Supplement Health and Education Act (DSHEA) created this claim category to let manufacturers describe how an ingredient supports normal body function without claiming to treat disease. FDA's label-claims guidance sets the boundary: a claim can describe a nutrient's role in maintaining structure or function, but it cannot imply diagnosis, cure, mitigation, treatment, or prevention of disease. That second category belongs to drugs and FDA-authorized health claims, not supplements.
21 CFR 101.93 and the Federal Register's 10-point framework from January 2000 spell out how FDA tells the two apart. Examples that usually pass muster versus wording that crosses the line:
- Acceptable: "Supports healthy joint function" or "Helps maintain normal cholesterol levels already within a healthy range."
- Prohibited: "Relieves arthritis pain" or "Lowers cholesterol" without the healthy-range qualifier, since both imply treating a diagnosed condition.
Context matters as much as the words themselves. A claim referencing a body system tied to a specific disease (say, blood sugar and diabetes) draws closer FDA scrutiny than one about general wellness.
Notification and Disclaimer Requirements Under 403(r)(6)
Section 403(r)(6) of the FD&C Act requires a specific notification, not a request for approval. FDA reviews it and can respond, but silence doesn't mean you're cleared. Regulatory specialists stress this point often: notifications are procedural, and firms need documentation showing they had substantiation in hand before the product ever shipped.
Here's the sequence to follow:
- Draft the exact claim text as it will appear on the label or labeling, word for word.
- Identify the product and dietary ingredient the claim is based on.
- Obtain the signature of a responsible company official who can attest to the claim's accuracy.
- Submit the notification to FDA no later than 30 days after first marketing the product with that claim.
- Retain a copy of the submission and any FDA correspondence, including courtesy letters raising objections.
The most common procedural failure is timing. Companies market a product with a new claim, then treat notification as an afterthought weeks or months later. A close second is submitting the notification but changing the label wording afterward without updating FDA. If the language on your bottle diverges from what you filed, you have effectively made an unnotified claim. Our FDA disclaimer requirement guide walks through exact placement rules so the disclaimer and the claim stay tied together on the physical label.
Building Substantiation That Holds Up Under Scrutiny
FDA does not publish a fixed evidence threshold for structure/function claims. That absence of a bright line is not a loophole. It shifts the burden onto you to build a record that would satisfy a skeptical FDA reviewer or FTC investigator, whichever comes knocking first. Legal analyses of the framework note that manufacturers must rely on the totality of the evidence rather than any single study, and document why that evidence supports the specific words on the label.
Evidence carries different weight depending on design:
- Randomized controlled trials on the specific ingredient, at the dose used in your product, carry the most weight.
- Well-designed observational studies add support but rarely stand alone.
- Mechanistic or in vitro research explains plausibility but doesn't substitute for human data.
- Systematic reviews and meta-analyses strengthen a claim when individual trials are small or mixed.
For multi-ingredient formulas, document the evidence chain for each active ingredient separately, then add a short rationale explaining why the combination supports the claim without drifting into disease territory.
Pro Tip: Build a one-page "claim dossier" for every statement on your label: the claim text, the key studies backing it with quality notes, known limitations, and a single sentence tying the evidence to the exact wording. This format turns a scattered research folder into something you can hand an FDA or FTC reviewer in minutes, not weeks.
Our guide on evaluating supplement clinical evidence breaks down which quality markers matter most when you're triaging dozens of studies into one defensible dossier.
Advertising vs. Labeling: Where FTC Enforcement Enters
FDA regulates what's on the label. The FTC regulates what's in your advertising, and the two agencies don't always draw the line in the same place. A claim that clears FDA's structure/function standard on the bottle can still trigger an FTC inquiry if your marketing copy pushes the same words further than the underlying evidence supports.
This split catches manufacturers off guard constantly. A label might say "supports joint comfort," carefully hedged and notified. Then a social media ad for the same product says "eliminates joint pain in days," a leap the label never made and the substantiation never covered.
Keep marketing and label claims in lockstep with a few guardrails:
- Route every ad and product page claim through the same review process as label copy, not a separate marketing sign-off.
- Match advertising language to the exact notified claim text, not a looser paraphrase.
- Flag testimonials and influencer content for disease-implication language before it publishes.
- Treat FTC's truthful-advertising standard as at least as strict as FDA's, since it often is.
A Step-by-Step Compliance Checklist for Manufacturers
Treat structure/function compliance as a workflow with checkpoints, not a one-time legal sign-off before launch.
- Draft the claim using structure/function language that describes a body function, never a disease outcome, symptom, or diagnosis.
- Assemble your substantiation dossier, prioritizing human clinical evidence and noting where mechanistic or observational data fills gaps.
- Place the mandatory disclaimer directly on the label near the claim, not buried in an insert or relegated to a website page.
- File the 403(r)(6) notification within 30 days of first marketing, using the exact claim text, and keep a dated copy of the submission.
- Cross-check marketing materials against the notified claim before any campaign or product page goes live.
- Monitor adverse event reports and FDA enforcement letters in your category for early warning signs that regulatory attitudes toward similar claims are shifting.
- Revisit the dossier annually or whenever new research on the ingredient publishes, so your substantiation doesn't quietly go stale.
Pro Tip: Set a recurring calendar reminder tied to your product launch date, not just your notification filing date. The 30-day clock starts at first marketing, which sometimes happens before your regulatory team even knows the product shipped.
Our FDA-compliant label requirements guide and 2026 supplement label checklist both map directly onto these steps if you want a longer walkthrough for your compliance team.
Where Compliance Breaks Down in Practice
Most enforcement actions trace back to a handful of repeat mistakes. The biggest is the implied disease claim: language that sounds like structure/function support but reads, in context, as a treatment promise. FDA weighs the whole label, not just the sentence in question, so a claim next to imagery of a specific disease state or a testimonial describing symptom relief can get reclassified even when the wording itself looks careful.
Disclaimer placement causes a steady stream of problems too. Small manufacturers frequently put the required disclaimer on a separate insert or their website instead of on the product label itself, right where the claim appears. That separation is a common trigger for FDA follow-up.
- Late or missing 403(r)(6) notifications remain a frequent, avoidable error.
- Disclaimer language altered from the required wording, even slightly, invites scrutiny.
- Marketing claims that outpace the notified label language draw FTC attention independent of FDA status.
Outcomes typically escalate from a courtesy letter, to a formal warning letter, to an advertising enforcement action if the FTC gets involved. Each stage gives you a window to correct course before penalties or product seizure enter the picture.
How NutraSmarts Supports Substantiation and Label Compliance
NutraSmarts maintains evidence-rated ingredient profiles linked to peer-reviewed studies, letting you pull a research summary instead of starting from a blank search. The free Supplement Facts label creator formats disclaimer placement and label fields correctly, so the compliance details covered above become a repeatable step in your workflow rather than a one-off legal review.
A Realistic Roadmap for Claims Compliance
Manufacturers that treat substantiation as a launch-day checkbox get caught eventually. The ones who stay clean build evidence into product development from the start, not after a claim is already printed. Centralize claim review so legal, regulatory, and marketing teams are reading the same dossier, not three different drafts. Keep the notification proof and the substantiation file together and current. That habit, more than any single filing, is what protects a company when scrutiny arrives.
— NutraSmarts
Turn Your Claim Dossier Into a Working Label
Most manufacturers lose time bouncing between spreadsheets, PDF studies, and label templates just to get one claim label-ready. NutraSmarts consolidates that work: evidence-rated ingredient profiles give you the study citations behind a claim in one place, and the free Supplement Facts label creator formats your disclaimer and label fields without a design file or a spreadsheet formula in sight.
If you're drafting a new structure/function claim, start by pulling the ingredient's evidence profile on NutraSmarts to see what research already exists before you write a word of label copy. It's a faster starting point than a blank search, and it keeps your substantiation dossier and your label language built from the same source.
This article is general information, not a substitute for advice from a qualified lawyer. Consult a qualified legal professional about your own circumstances before acting on anything here.