One sentence on your product label can be the difference between a compliant dietary supplement and an unapproved new drug — at least in the eyes of the FDA. Over my eight-plus years advising more than 200 dietary supplement, food, and beverage companies, I've watched this single issue — the line between structure-function claims and drug claims — generate more Warning Letters, import alerts, and consent decrees than almost any other labeling topic.
This guide is designed to be the most practical, thorough resource available on the subject. Whether you're formulating a new product, reviewing existing labels, or preparing for a regulatory audit, understanding these distinctions isn't optional — it's foundational.
What Are FDA Label Claims, and Why Do They Matter?
FDA label claims describe the relationship between a product (or its ingredients) and the human body. The type of claim you make determines how your product is regulated — as a food, a dietary supplement, or a drug — and therefore what rules, pre-market requirements, and enforcement risks apply.
Get this wrong and you're not facing a minor paperwork issue. You're potentially marketing an unapproved new drug without FDA approval, which carries significant legal exposure including product seizure, injunctions, and criminal prosecution.
Citation hook: Under 21 U.S.C. § 321(g)(1)(B), a product is legally classified as a drug if its labeling claims it is "intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease" — regardless of what the manufacturer believes it to be.
The Four Main Types of FDA Label Claims
Before diving into structure-function versus drug claims specifically, it helps to understand where those categories sit within the broader FDA claim landscape.
| Claim Type | Regulatory Basis | Pre-Market FDA Approval? | Applies To |
|---|---|---|---|
| Nutrient Content Claim | 21 CFR Part 101 | No (must meet defined criteria) | Foods, supplements |
| Health Claim | 21 CFR 101.14 | Yes (authorized) or significant scientific agreement | Foods, supplements |
| Qualified Health Claim | FDA Modernization Act 1997 | Petitioned; requires disclaimer | Foods, supplements |
| Structure-Function Claim | 21 CFR 101.93 / DSHEA 1994 | No (notification required) | Dietary supplements, conventional foods |
| Disease Claim (Drug Claim) | 21 U.S.C. § 321(g) | Yes — full NDA/BLA required | Drugs only |
Understanding which column your label language falls into is the entire game.
Structure-Function Claims: The Fundamentals
What Is a Structure-Function Claim?
A structure-function claim describes the role of a nutrient or dietary ingredient in affecting the normal structure or function of the human body. These claims are authorized under the Dietary Supplement Health and Education Act (DSHEA) of 1994 for dietary supplements, and have a parallel pathway for conventional foods.
Examples of permissible structure-function claims:
- "Calcium builds strong bones."
- "Fiber maintains bowel regularity."
- "Zinc supports immune function."
- "Vitamin C contributes to normal collagen formation."
These statements describe what the ingredient does in a healthy body. They do not reference any disease state, and they do not imply the product will cure, treat, mitigate, or prevent any condition.
The Three Requirements for a Lawful Structure-Function Claim
Under 21 CFR 101.93 and FDA's 2000 final rule on structure-function claims, a dietary supplement manufacturer must meet three criteria to use a structure-function claim legally:
- Substantiation: The claim must be truthful, not misleading, and substantiated by competent and reliable scientific evidence.
- Disclaimer: 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."
- Notification: The manufacturer must notify FDA within 30 days of first marketing a product with a structure-function claim (21 CFR 101.93(a)).
Citation hook: FDA's 2000 final rule on structure-function claims established that claims must be based on the product's effect on "the structure or function of the body in general," not on any disease state — a distinction that turns entirely on the wording, context, and consumer perception of the claim.
Drug Claims: Where the Line Gets Drawn
What Triggers a Drug Claim?
A claim crosses into drug claim territory when it explicitly or implicitly suggests the product is intended to:
- Diagnose a disease or condition
- Cure a disease or condition
- Mitigate (lessen) a disease or condition
- Treat a disease or condition
- Prevent a disease or condition
This is the "DCTMP" framework, and it comes directly from the statutory definition of a drug at 21 U.S.C. § 321(g)(1)(B).
The Explicit vs. Implied Drug Claim Problem
Most manufacturers know not to write "This product cures diabetes" on their label. The real danger lies in implied drug claims — language that a reasonable consumer would interpret as disease-related, even without using the word "disease."
FDA evaluates label claims holistically, considering:
- The name of the product itself (e.g., "ArthriEase" or "DiabetAssist" suggest disease treatment)
- Product labeling and company website copy, ads, and social media
- Statements made by sales representatives
- Consumer testimonials posted on company-controlled platforms
- The overall context and imagery of the label
According to FDA's Warning Letter database, implied disease claims on websites and social media are among the top three enforcement triggers for dietary supplement companies — and FDA absolutely considers off-label digital marketing as part of a product's labeling for regulatory purposes.
Structure-Function vs. Drug Claims: Side-by-Side Comparison
This is the table I walk every client through during label reviews. Small word changes make a massive regulatory difference.
| Intended Meaning | Permissible Structure-Function Claim | Impermissible Drug Claim |
|---|---|---|
| Bone health | "Supports healthy bone density" | "Prevents osteoporosis" |
| Blood sugar | "Helps maintain healthy blood sugar levels already within the normal range" | "Lowers blood sugar in diabetics" |
| Cardiovascular | "Supports healthy cholesterol levels already within the normal range" | "Reduces the risk of heart disease" |
| Immunity | "Supports immune function" | "Prevents colds and flu" |
| Joint health | "Promotes comfortable joint movement" | "Treats arthritis pain" |
| Mental health | "Supports a positive mood" | "Treats depression" |
| Gut health | "Supports healthy digestion" | "Treats irritable bowel syndrome" |
| Weight | "Supports healthy weight management" | "Treats obesity" |
Notice the pattern: structure-function language describes support of normal function in a healthy individual. Drug claims name a disease and assert treatment, prevention, cure, or mitigation.
The phrase "already within the normal range" is not just clever wordsmithing — it's a substantive legal distinction that signals the product is intended for healthy people maintaining normal parameters, not for patients managing a diagnosed condition.
The "Disease" Definition: Broader Than You Think
One of the most common mistakes I see is manufacturers assuming that only formal medical diagnoses constitute "diseases" under FDA's framework. FDA's 2000 final rule (65 FR 1000) defines disease as:
"…damage to an organ, part, structure, or system of the body such that it does not function properly (e.g., cardiovascular disease), or a state of health leading to such dysfunctioning (e.g., hypertension)…"
This definition is intentionally broad. It includes:
- Common conditions not typically thought of as "diseases" — FDA has clarified that morning sickness, hot flashes, and mild memory problems associated with aging can still fall under this definition in context
- Symptoms associated with disease — claiming a product "relieves chest tightness" can imply cardiovascular disease treatment
- Disease risk factors — claiming to "lower high blood pressure" implies treating hypertension, a disease
Citation hook: FDA's 2000 final rule explicitly states that a claim referencing a sign, symptom, or characteristic that is "recognizable to consumers as being associated with a disease" constitutes an implied disease claim, even if the word "disease" never appears on the label.
High-Risk Claim Areas: Where Companies Most Often Go Wrong
Based on my work with clients and analysis of FDA Warning Letters from 2018 through 2024, the highest-risk claim categories are:
1. Cancer Claims
Any reference to "anti-tumor," "anti-carcinogenic," "anti-cancer," or even "supports cellular health" combined with cancer-adjacent marketing language is extremely high risk. FDA has issued Warning Letters for claims like "antioxidants that fight free radical damage" when paired with cancer-related website content.
2. COVID-19 and Infectious Disease Claims
Between 2020 and 2022, FDA issued more than 500 Warning Letters to companies making COVID-19-related claims on dietary supplements. Statements like "boosts immunity to fight COVID" are unambiguous drug claims regardless of the underlying ingredient.
3. Mental Health and Neurological Claims
"Supports a calm, focused mind" is likely permissible. "Reduces anxiety disorder symptoms" is not. The former describes normal cognitive function; the latter names a DSM-diagnosed condition. This is a thin line that mental wellness brands frequently cross.
4. Metabolic and Endocrine Claims
Weight management, blood sugar, and thyroid-related claims are among the most scrutinized categories. FDA considers any claim referencing insulin sensitivity, glucose regulation in diabetics, or thyroid hormone levels to be drug claims.
5. Pediatric and Pregnancy Claims
Claims related to developmental conditions (e.g., ADHD, autism spectrum) or pregnancy complications (e.g., preeclampsia) are virtually always drug claims. Even softened language like "may support focus in children with attention challenges" is a drug claim.
The Substantiation Requirement: You Need Science Behind Every Claim
Many companies treat substantiation as an afterthought. It shouldn't be. The FTC and FDA both have authority over supplement claim substantiation, and the standard is "competent and reliable scientific evidence" — typically interpreted as randomized controlled human clinical trials or, at a minimum, a body of consistent peer-reviewed research.
Key substantiation principles:
- Ingredient-level evidence is not automatically product-level evidence. Studies on isolated curcumin extract at 500mg don't automatically substantiate claims for a product containing 50mg of generic turmeric powder.
- Mechanistic studies and animal studies are generally insufficient to substantiate structure-function claims on their own.
- The studied population must match your product's intended users. A study conducted in elderly, deficient populations doesn't substantiate a claim for a healthy adult supplement.
- Dosage must be comparable. The clinical dose in the study should align with the dose in your product.
According to a 2022 GAO report, the FDA receives tens of thousands of structure-function claim notifications annually, yet resources for active enforcement remain limited — which does not mean enforcement is rare, only that it is targeted and often triggered by consumer complaints or competitive intelligence.
The 30-Day Notification Requirement: Don't Skip It
Under 21 CFR 101.93(a), dietary supplement manufacturers must submit a notification to FDA no later than 30 days after first marketing a product with a structure-function claim. The notification must include:
- The text of the claim
- The name and address of the manufacturer or distributor
- A certification that the manufacturer has substantiation for the claim
This notification does not constitute FDA approval or endorsement of the claim. FDA will respond with a letter confirming receipt, and the claim remains the manufacturer's legal responsibility. Failure to notify is an independent violation — companies have received Warning Letters solely for missing this requirement even when the underlying claim was permissible.
Website and Social Media: The Overlooked Labeling Risk
Under 21 CFR 1.3(b), FDA defines "labeling" broadly to include all written, printed, or graphic matter accompanying a product — which courts have interpreted to include a company's website when it promotes a specific product.
This means:
- A blog post on your website claiming your probiotic "cures leaky gut syndrome" can reclassify your probiotic as a drug
- An Instagram caption stating your turmeric supplement "fights cancer" is labeling, not free speech
- Customer testimonials you curate and display on your product page are, for regulatory purposes, your claims
Best practice: Conduct a full digital audit alongside every label review. Your label may be perfectly written while your website is generating Warning Letter exposure.
How to Build a Compliant Label Review Process
Here's the systematic approach I use at Certify Consulting when reviewing label claims for clients:
Step 1: Identify Every Claim
List every explicit and implied claim across the label, including: product name, front panel statements, back panel copy, directions for use, and any structure-function claim disclosures.
Step 2: Classify Each Claim
Apply the DCTMP test to each statement. Ask: "Would a reasonable consumer interpret this as suggesting the product diagnoses, cures, mitigates, treats, or prevents a disease?"
Step 3: Evaluate the Disease Definition
For borderline claims, apply FDA's 2000 final rule disease definition. Does the claim reference a condition that is "damage to an organ, part, structure, or system such that it does not function properly"?
Step 4: Review Supporting Science
For each surviving structure-function claim, document the substantiation file. Confirm dosage alignment, population relevance, and study quality.
Step 5: Audit Digital Presence
Review all company-controlled digital content for claims that could be attributed to the product.
Step 6: Confirm Disclaimer and Notification
Verify the mandatory disclaimer is present on all labeling and that a 30-day notification has been submitted to FDA.
Enforcement Landscape: What the Numbers Tell Us
Understanding FDA's enforcement priorities helps contextualize risk:
- FDA issues approximately 100–200 dietary supplement Warning Letters per year, with label claims being the most common cited violation category.
- The FTC filed 29 enforcement actions related to dietary supplement advertising claims between 2019 and 2023, many involving implied disease claims on digital platforms.
- Import alerts related to unapproved new drug claims have affected hundreds of foreign-manufactured supplement brands attempting to enter the U.S. market.
- Products marketed for weight loss, sexual enhancement, and bodybuilding are the three highest-frequency targets for FDA sampling and Warning Letter issuance, according to FDA's annual dietary supplement report.
These numbers underscore a critical reality: the FDA does not catch every violation, but when it does, the consequences are disproportionately severe relative to the cost of proactive compliance.
Working With a Regulatory Consultant: What to Expect
At Certify Consulting, my team has helped clients across the dietary supplement, functional food, beverage, and medical food categories navigate label claim compliance with a 100% first-time audit pass rate. Our label review process typically involves:
- Full claim classification against the DCTMP framework
- Substantiation file review and gap analysis
- Digital content audit
- Competitor benchmarking to identify industry norms and risk levels
- 30-day notification preparation and submission support
- Written regulatory opinion letter for manufacturer records
If your company is introducing a new product line, reformulating, or has received a Warning Letter, a professional label review is one of the highest-ROI compliance investments available. Learn more about how we support supplement companies at thefdaexpert.com or visit our full consulting services overview.
Key Takeaways
- The legal distinction between structure-function and drug claims turns on a single question: Does the claim imply the product diagnoses, cures, mitigates, treats, or prevents a disease?
- Implied claims are as legally dangerous as explicit claims. Product names, website copy, testimonials, and social media posts all count as labeling.
- FDA's disease definition is broader than common usage — it includes conditions consumers associate with disease, not just formal diagnoses.
- Every structure-function claim requires substantiation, a disclaimer, and a 30-day notification to FDA — all three, not just the disclaimer.
- A holistic compliance review covers the label and all company-controlled digital content.
Last updated: 2026-03-25
Jared Clark, JD, MBA, PMP, CMQ-OE, CPGP, CFSQA, RAC is the Principal Consultant at Certify Consulting, with 8+ years of FDA regulatory experience and a 100% first-time audit pass rate across 200+ clients. Visit certify.consulting for more.
Jared Clark
Principal Consultant, Certify Consulting
Jared Clark is the founder of Certify Consulting, helping organizations achieve and maintain compliance with international standards and regulatory requirements.