Supports Immune Health Is Allowed. Prevents the Flu Is Not. Here Is Where Your Store Crosses the Line.

The line is not subtle. A dietary supplement can say it “supports immune health.” It cannot say it “prevents the flu.” One describes what the body does. The other names a disease and claims to stop it. Under DSHEA, that distinction determines whether you are selling a supplement or, in regulators’ eyes, an unapproved drug.

Most stores know this in theory. Where they get into trouble is in practice: the collection page headline a marketer wrote during cold-and-flu season, the product description imported from a manufacturer’s feed, the email subject line that went out in January. The claim does not have to be on the label to count. The FTC treats every consumer-facing touchpoint as an advertising claim, and it enforces accordingly.

The question is not just whether your label is clean. It is whether your store is.

What is the difference between a structure/function claim and a disease claim?

A structure/function claim describes what a nutrient or ingredient does to a healthy body. A disease claim describes what a product does to a sick one.

FDA’s Small Entity Compliance Guide lays out 10 criteria for telling them apart. The most useful one is also the simplest: does the statement mention or imply a specific disease or class of diseases? If yes, it is a disease claim. No premarket approval exists for that on a supplement. The product is now regulated as a drug, and you are not selling a drug.

The word “prevents” is almost always the tell. So are “treats,” “cures,” “fights,” and “relieves” when paired with a named condition. But the line is not purely about word choice. Context matters too. A claim that says “helps maintain cholesterol levels already within the normal range” survives because it describes maintenance of a healthy state. “Lowers cholesterol” fails because elevated cholesterol is a recognized disease marker, and the claim implies treatment.

The test: Is the product being positioned as something a healthy person takes to stay healthy, or something a sick person takes to get better? The first is a supplement. The second is a drug.

Where the words are safe

These are illustrative examples of claims that describe function without naming disease:

• “Supports immune health”
• “Promotes healthy inflammatory response”
• “Helps maintain cardiovascular function”
• “Supports a healthy stress response”
• “Promotes joint health and flexibility”

Where the words cross the line

These are illustrative examples of claims that name or imply disease:

• “Prevents colds and flu”
• “Reduces inflammation” (without the “already within normal range” qualifier)
• “Fights infection”
• “Relieves joint pain”
• “Helps manage blood sugar in people with diabetes”

The difference between the two lists is not marketing boldness. It is regulatory category.

Where does a store cross the line without realizing it?

The label is not the only place regulators look. FDA evaluates the entire labeling context, which includes anything accompanying the product: the product page, the collection description, the insert in the box. The FTC goes further. It treats any consumer-facing representation as an advertising claim subject to substantiation, regardless of where it appears.

That means three places in your Shopify store deserve the same scrutiny as the physical label.

The collection page headline

A collection called “Immune Support” is fine. It is a category descriptor. But the headline above the grid often says something else: “Stay protected this winter” or “Fight back against seasonal illness.” Those phrases do not describe a function. They describe a defensive action against a disease event. The collection page is consumer-facing copy. The FTC reads it.

The merchandising blurb

The short paragraph below the collection title, the one that explains what the category is about, is where stores tend to editorialize. “Our immune formulas are designed to keep you healthy when everyone around you is getting sick” sounds like marketing. To a regulator, it sounds like a prevention claim. “When everyone around you is getting sick” is context that implies the product works on disease exposure, not on normal immune function.

Imported manufacturer copy

This is the highest-risk surface for most stores. A manufacturer writes a product description that says “clinically shown to reduce the duration and severity of cold symptoms.” You import it via a feed. It goes live on your PDP. You did not write it, but it is on your store, and you are the seller. FDA and the FTC hold the seller responsible for claims made on the product page, regardless of who authored them.

The practical implication: every claim in your catalog, regardless of its source, is your claim the moment it goes live on your storefront.

Does the FDA gray area protect you from the FTC?

FDA acknowledges that the boundary between structure/function and disease claims is not always perfectly clear. The FTC does not draw that line at all. It does not ask which category a claim falls into. It asks only whether the claim is truthful, not misleading, and substantiated by competent and reliable scientific evidence before the claim is made.

“Before the claim is made” is the operative phrase. There is no post-hoc correction path where you make the claim, wait to see if a regulator objects, and then fix it. The substantiation has to exist first.

More importantly, the FTC does not distinguish between a claim on the label and a claim in an ad, on a website, or in an email. The FTC’s Health Products Compliance Guidance makes clear that all consumer-facing representations are held to the same standard. A disease claim in your Google Shopping feed is treated the same as one on your bottle.

This is why the FDA gray area gives a store no cover. The FTC’s practical position is simple: if a claim is close enough to a disease claim that a reasonable consumer might read it that way, it is held to the substantiation that claim would require. The benefit of the doubt goes to the consumer, not the store.

Key takeaway: The gray area in the FDA guidance is not a safe harbor. It is a description of how hard these determinations can be. The FTC does not grade on a curve.

How do you audit your own store for disease claims?

You do not need a compliance attorney to do a first pass. You need a disciplined read of the copy that actually faces customers.

Work through these five checks on every surface where claims appear: collection pages, PDPs, email templates, ad copy, and any manufacturer descriptions you have imported.

1. Does the copy name a disease? Look for explicit disease names (flu, cold, arthritis, diabetes, depression) and for disease synonyms (infection, inflammation, high blood pressure). Either one triggers the disease claim threshold.

2. Does the copy describe a sick-person use case? Phrases like “when you’re feeling run down,” “during cold season,” or “when everyone around you is getting sick” imply the product is for someone who is already ill or imminently threatened by illness. That is disease territory.

3. Does the copy use drug-class language? Words like “antiviral,” “antibacterial,” “antibiotic,” “analgesic,” or “anti-inflammatory” belong to drug categories. Using them on a supplement is an implied disease claim even if no disease is named.

4. Does the product name itself make a claim? A product called “Cold Fighter” or “Flu Shield” carries an implied disease claim in the name. The name is part of the labeling context.

5. Did you audit the manufacturer copy before it went live? If you imported product descriptions from a supplier feed without reviewing each one, this is the first thing to fix. Build a review step into your import workflow. One unreviewed PDP with “reduces cold duration” is enough to create exposure across the entire catalog.

This is not an exhaustive compliance review. It is a first filter. If a claim fails any of these checks, it needs to be rewritten before it goes live, not after.

Why is a compliance problem also an AI visibility problem?

There is a second reason to get this right beyond regulatory risk. AI answer engines, including ChatGPT, Perplexity, and Gemini, are increasingly where supplement buyers go to research what to take. Those engines are trained to be careful about health claims. A product page loaded with disease-adjacent language is less likely to be cited, not more. The copy that sounds boldest to a human reader often reads as unreliable to a model.

Compliant claims, written with precision, are also the claims that AI engines can quote without hesitation. “Supports immune health” is a statement a model can cite. “Prevents the flu” is one it will not repeat, because the model has been trained to avoid making medical promises.

Getting the claims right is not just about staying out of trouble with the FTC. It is about writing copy that works in the environment your buyers are actually using.

If you want a read on where your catalog currently stands, Taranoki’s free audit reviews your claims against FTC and FDA standards and flags the specific pages and phrases that create exposure.