Supplement allergen labels follow one US rule set: if a product contains one of nine major allergens, the label must say so in plain words. The law applies to dietary supplements the same way it applies to packaged food. This guide shows what the rule covers and how to read the fine print on a bottle.
The nine major allergens
Congress passed the Food Allergen Labeling and Consumer Protection Act (FALCPA) in 2004. It named eight major allergens: milk, eggs, fish, crustacean shellfish, tree nuts, peanuts, wheat, and soybeans. At the time, those eight caused about 90 percent of food allergies and serious allergic reactions in the US, according to the FDA.
The ninth is sesame. The FASTER Act became law on April 23, 2021, and it made sesame a major allergen. The change took effect on January 1, 2023. From that date, the same labeling and manufacturing rules that cover the other eight also cover sesame.
Do the rules reach supplements?
Yes. The FDA says it enforces the law in most packaged food products, and that this includes dietary supplements. The listed exceptions are meat, poultry and egg products run by the USDA, alcoholic beverages under another agency, raw farm products, highly refined oils, drugs, and cosmetics.
So a capsule, powder or gummy sold as a supplement must follow the same allergen rules as a box of crackers. That matters because supplements often use fillers and carriers that come from food, such as soy lecithin or whey. Those two show up on the FDA's own examples of how a source can be named.
How the label must name an allergen
The law says the label must name the food source of every major allergen in the product. A maker can do this in one of two ways. The first is to put the source in parentheses inside the ingredient list, such as "lecithin (soy)" or "whey (milk)". The second is a "Contains" line right after or next to the ingredient list, such as "Contains wheat, milk, and soy."
Some allergens need more detail. The label must give the type of tree nut, such as almond, pecan or walnut. It must give the species of fish, such as cod or bass, and the kind of crustacean shellfish, such as crab, lobster or shrimp. "Tree nuts" alone is not enough.
Some terms are read narrowly. The FDA treats "milk" as milk from the domesticated cow and "eggs" as chicken eggs. Milk from goats or eggs from ducks are not covered by that wording, even though the proteins are similar. If you have a question about those, ask a health care provider.
What the sesame rule changed
Since January 1, 2023, sesame has to be named like the other eight when it is an ingredient, in the ingredient list or in a Contains line.
There was a transition. The FDA said products already in interstate commerce before January 1, 2023 did not have to be pulled or relabeled. A bottle made earlier could still be on a shelf without a sesame line. The agency told shoppers to check with the maker or distributor if they were unsure.
How to read "may contain" statements
You may see lines such as "may contain peanuts" or "made in a facility that also uses milk." These are advisory statements. The FDA says they are not required by law.
The agency says makers can use them to address unavoidable cross-contact, but only if they follow good manufacturing practices and take every precaution to prevent it. Cross-contact can happen when different foods share equipment or a production line, when cleaning is poor, or when dust or aerosols carry an allergen. The FDA also says an advisory line is not a substitute for good manufacturing practices, and it must be truthful and not misleading.
Two points follow from this. First, a missing "may contain" line does not prove a product is free of an allergen. Second, the FDA has not set a threshold for any allergen, meaning there is no legal amount below which a trace is considered safe. A simple habit helps: read the ingredient list, then the Contains line, then any advisory line, and contact the maker if something is unclear.
A short checklist for buyers
- Read the full ingredient list, including capsule shells, coatings and flavors.
- Look for the source in parentheses or a Contains line.
- Check for sesame on bottles made before 2023.
- Treat advisory lines as a signal, not a guarantee either way.
- Ask the maker when the label is vague.
This article is general information about labeling rules, not personal advice.
Sources
- U.S. Food and Drug Administration, "Food Allergies," fda.gov/food/food-labeling-nutrition/food-allergies (archived copy dated September 19, 2023).