Pick up a bottle of elderberry in a drugstore in January. The front probably says something like “supports immune health.” It almost certainly does not say “prevents colds.”
That’s not modesty. It’s federal law, and the line between those two sentences is one of the most consequential rules in American consumer health. Once you can see it, every supplement label in the store reads differently.
This is the rule in one sentence. A dietary supplement may claim that an ingredient supports, maintains or affects a normal structure or function of the body. The moment it claims to treat, prevent, cure or mitigate a disease, it stops being a supplement in the eyes of the law and becomes an unapproved drug.
Everything else on the label flows from that. The hedged verbs, the vague nouns, the asterisk, the small print on the back. None of it is accidental.
Structure and function on one side, disease on the other
The rule lives in federal regulation at 21 CFR 101.93. Paragraph (f) says a label may describe the role of a nutrient or dietary ingredient in affecting a structure or function in humans, or describe the documented mechanism by which it maintains that structure or function. The same paragraph says that if a product bears a disease claim, it is regulated as a drug, unless the claim is an authorized health claim the product qualifies for.
The regulation also defines what counts as a disease. It’s “damage to an organ, part, structure, or system of the body such that it does not function properly,” or a state of health leading to that kind of dysfunction. Nutrient deficiency diseases such as scurvy and pellagra are carved out, which is why a vitamin C product can legally mention scurvy when nothing else can mention a disease.
That’s the whole architecture. “Supports a healthy inflammatory response” is a structure/function claim. “Relieves arthritis” is a drug claim. The ingredient inside the capsule can be identical.
How FDA decides a claim crossed the line
This is where the rule gets more interesting than most people expect, because FDA does not just look for disease names. The regulation lists ten ways a statement can become a disease claim, and several of them catch things that are never said out loud.
A claim crosses the line if it refers to a specific disease or class of diseases. It also crosses if it refers to the characteristic signs or symptoms of a disease, in plain language or technical language. So “supports healthy blood sugar” and “lowers high blood sugar” sit on opposite sides, and the second one is a drug claim even though it never says diabetes.
The product’s own name can be a disease claim. So can the formulation, if the product contains an ingredient well known for treating a disease. So can a citation to a published study, if the study is about treating disease and the context implies the product does the same. So can a picture, a symbol or a vignette. A heartbeat tracing across the front panel, an image of a swollen joint, a cartoon of a clogged artery: all of those can convert a legal structure/function claim into an illegal drug claim without a single word changing.
FDA says explicitly that it considers context. That’s why reading one phrase in isolation can mislead you about what a package is really communicating.
The asterisk you have read a thousand times
Every structure/function claim has to carry a disclaimer, and the wording is fixed by regulation. You cannot modify it. It reads: “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 formatting is regulated too. The disclaimer must sit immediately next to the claim with nothing in between, or be linked to it by a symbol such as an asterisk and set off in a box on the same panel. It has to be in boldface type, no smaller than one sixteenth of an inch.
Most people read that sentence as a shrug. It’s a precise statement, and the precision is the point.
It does not mean FDA looked at the claim and disagreed. It means FDA never looked at all. Under 21 CFR 101.93, a company making a structure/function claim must notify FDA no later than 30 days after it starts marketing the product. The notification includes the firm’s name and address, the exact text of the statement, the ingredient involved and the product name. A responsible person signs it, certifying that the firm holds substantiation that the claim is truthful and not misleading.
Read that sequence again. The notice arrives after the product is already on shelves. The evidence stays with the company. Nobody at FDA reviews or approves it as part of that process. The disclaimer is telling you that the burden of proof was never externally checked, which is useful information, just not the information most shoppers think they’re getting.
Four kinds of claims, and only two get reviewed
Supplement and food labels carry four categories of claim, and they are not equally serious.
Nutrient content claims describe how much of a nutrient is present. These are defined in regulation with actual numbers. “High” in a nutrient requires at least 20 percent of the Daily Value per serving. “Good source” requires 10 to 19 percent. “High potency” for a single vitamin or mineral means 100 percent or more of the reference daily intake. These words mean something specific, which makes them among the most trustworthy words on a package.
Health claims describe a relationship between a substance and a disease or health-related condition. These require significant scientific agreement among qualified experts and FDA authorization through rulemaking. There are relatively few of them, and they’re the closest thing to a government-vetted health statement on a food or supplement label.
Qualified health claims sit one rung down. FDA’s guidance describes these as claims supported by credible evidence that falls short of significant scientific agreement. A company petitions FDA, and if the evidence is credible, FDA issues a letter of enforcement discretion specifying the exact wording it won’t object to. FDA is clear that it does not approve these petitions, and the claim must carry qualifying language that conveys how weak the evidence is.
Structure/function claims require no preapproval and no evidence review. Just the disclaimer and the 30-day notice.
This is the practical upshot. The overwhelming majority of claims you read on supplement packaging are in the fourth category, the one with the least oversight. The categories with real scientific review are the ones you almost never see.
FDA writes the label rules, and FTC polices the ad
This split surprises people, and it explains a lot of marketing behavior.
FDA has primary responsibility for claims in labeling: the package, the insert, point-of-sale material. The Federal Trade Commission has primary responsibility for claims in advertising, which covers television, print, websites, email, social posts and search ads.
The FTC published its Health Products Compliance Guidance in December 2022, replacing a 1998 advertising guide for dietary supplements. It applies well beyond supplements, covering foods, over-the-counter drugs, homeopathic products, health equipment, diagnostic tests and health apps.
Three things in it matter to anyone reading an ad.
First, substantiation. An advertiser must have adequate support for an objective product claim before the ad runs. For health benefit and safety claims, the standard is competent and reliable scientific evidence, meaning research conducted and evaluated objectively by qualified experts using procedures generally accepted as yielding accurate results. FTC says randomized controlled trials are generally what’s needed for health benefit claims, and that animal studies, test-tube studies and testimonials are usually not enough on their own.
Second, FTC analyzes what an ad communicates, not only what it literally says. The guidance describes a two-step process: figure out what express and implied claims the ad conveys to consumers, then ask whether the evidence supports those claims. An implied claim counts.
Third, and this is the part almost nobody knows: FTC says the disclaimer required under the Dietary Supplement Health and Education Act of 1994, the law known as DSHEA that set up this whole system, does not cure a deceptive health claim. The asterisk on the back of the bottle is not a legal shield. If the ad conveys a disease claim, the disclaimer doesn’t fix it.
FTC also notes that it does not sort health claims into categories the way FDA does, and it does not require preapproval or notification for structure/function claims. And although FDA handles labeling, FTC has stated its jurisdiction isn’t limited by that division. The same sentence can be legal on a package and actionable in an ad.
Putting the claim in someone else’s mouth doesn’t work
The obvious workaround is to let a customer or an influencer say the thing the brand can’t say. FTC closed that door a long time ago.
The agency’s Endorsement Guides, revised in 2023, hold that an endorsement cannot be used to make a claim the product’s marketer could not legally make on its own. So a disease claim isn’t laundered by routing it through a testimonial, a creator video or a customer quote on a landing page. The advertiser remains responsible for substantiating the objective claims an endorsement conveys, and endorsers themselves can be liable for statements that go beyond their own experience.
There’s a second rule worth knowing when you read testimonials. An ad built on an exceptional or above-average outcome has to tell you what people generally achieve, unless the advertiser can prove the exceptional outcome is the ordinary one. “I lost 60 pounds” without that context is a problem, not a feature.
FTC adds that its guidance provides no safe harbor. Whether something is deceptive depends on the facts. How and when influencers must disclose a paid relationship is a separate subject, covered in its own article on this site.
How to read a claim for what it isn’t saying
This is a reading method, built for this article. Run any health claim through it in about ten seconds.
Check the verb. Supports, promotes, maintains, helps and contributes are structure/function verbs. Treats, prevents, relieves, cures, reverses and lowers are disease verbs. If a package uses only the first set, the company is telling you, in the one place it’s legally required to be careful, that it isn’t claiming a medical effect.
Check the noun. “Supports a healthy immune system” attaches the verb to a normal body function. “Reduces cold symptoms” attaches it to a disease state. The noun carries more information than the verb.
Ask who the subject is. Many claims are about an ingredient, not the product. “Vitamin C contributes to normal immune function” is a statement about vitamin C. It says nothing about whether this bottle contains a useful amount of it.
Ask what the study was on. “Clinically studied ingredient” means a study exists on that ingredient somewhere, at some dose, in some population. It does not mean this product was tested, or that the dose here matches the studied dose.
Notice the pictures. Charts, body diagrams, lab coats and before-and-after images often carry the implied claim the words carefully avoid.
Treat the disclaimer as information. It tells you no outside body evaluated this statement. That’s not a scandal. It’s a fact about the review process, and it should calibrate how much the sentence above it is worth.
What the rules don’t do
This is the honest trade-off. This framework does a decent job of keeping outright drug claims off supplement labels. It does very little to tell you whether a legal claim is a good one.
A structure/function claim can be truthful, properly substantiated and completely useless to you. “Supports energy metabolism” is defensible for almost any B vitamin, because B vitamins participate in energy metabolism in everyone, including people with no deficiency and no symptoms. Nothing about that claim predicts that you will feel more energetic.
The marketing effect of vague claims is measurable. A 2020 content analysis in BMJ Open examined 227 webpages returned by Google searches in Canada and the United States for “boost immunity” combined with “coronavirus” in April 2020. Immune boosting was portrayed as beneficial for avoiding COVID-19 on 85.5 percent of pages, and supplements were portrayed as beneficial on 40 percent, with commercial sites more likely to make those portrayals. Fewer than 10 percent of pages offered any critique of the idea. The authors’ point is subtle and important: pairing real advice such as sleep and diet with an unproven phrase like immune boosting helps legitimize the phrase, turning it into a marketing tool.
Enforcement is also uneven. A 2002 study in Family Medicine reviewed 61 websites about herbal supplements and cancer found through searches run in late 2000. Among the commercial sites, 92 percent discussed prevention, 89 percent discussed treatment and 58 percent discussed cure, while only 36 percent carried the required DSHEA disclaimer. Commercial sites cited referenced research 31 percent of the time, against 93 percent for noncommercial sites. That study is old, and the web has changed, but it documents the core dynamic: the rules on the package are tighter than the rules people follow online.
When a claim should send you to a clinician
Some claims are a signal to stop and get advice, not just weak.
If a product is marketed as an alternative to a prescription you take, or as something you can switch to, talk to your prescriber before changing anything. That applies especially to blood pressure, blood sugar, thyroid, blood thinning and mental health medications.
If marketing says a product works “as well as” a named drug, treat that as a disease claim wearing a costume, and treat the seller as unreliable about everything else.
If you have a diagnosed condition and you’re considering a supplement for it, bring the bottle to your appointment. Real interactions exist, and NIH’s Office of Dietary Supplements documents them. Vitamin K can weaken warfarin. St. John’s wort makes the body clear many medicines faster. Some supplements raise bleeding risk, which matters before surgery.
And if you’re taking something for a symptom that isn’t improving, that’s a reason to get the symptom looked at, not a reason to increase the dose.
The one test worth remembering
Verb and noun. That’s it.
If the verb is supportive and the noun is a normal body function, you’re reading the strongest claim US law allows a supplement to make without becoming a drug. That claim required no government review, no published evidence and no advance notice. It required a company to hold substantiation it never has to show you.
Knowing that doesn’t mean the product is worthless. It means the sentence on the front of the box was never evidence in the first place, and you’ll have to look somewhere else for that.
Sources
- US Food and Drug Administration. “Dietary Supplement Labeling Guide: Chapter VI, Claims.” fda.gov
- Electronic Code of Federal Regulations. “21 CFR 101.93: Certain Types of Statements for Dietary Supplements.” ecfr.gov
- Federal Trade Commission. “Health Products Compliance Guidance.” ftc.gov
- Federal Trade Commission. “FTC’s Endorsement Guides: What People Are Asking.” ftc.gov
- Electronic Code of Federal Regulations. “16 CFR Part 255: Guides Concerning the Use of Endorsements and Testimonials in Advertising.” ecfr.gov
- US Food and Drug Administration. “Label Claims for Conventional Foods and Dietary Supplements.” fda.gov
- US Food and Drug Administration. “Qualified Health Claims.” fda.gov
- US Food and Drug Administration. “Dietary Supplements.” fda.gov
- National Institutes of Health, Office of Dietary Supplements. “Dietary Supplements: What You Need to Know.” ods.od.nih.gov
- PubMed. “Rachul C et al. “COVID-19 and ‘immune boosting’ on the internet: a content analysis of Google search results.” BMJ Open, 2020. DOI: 10.1136/bmjopen-2020-040989.” doi.org
- PubMed. “Bonakdar RA. “Herbal cancer cures on the Web: noncompliance with The Dietary Supplement Health and Education Act.” Family Medicine, 2002. PMID: 12144007.” pubmed.ncbi.nlm.nih.gov