Supplements follow food-allergen labeling law
Dietary supplements are regulated as a category of food, so they must follow the same major-allergen labeling rules as packaged foods. Under the Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA), labels must clearly identify the major food allergens [1]. The FASTER Act of 2021 added sesame as the ninth major allergen, effective January 1, 2023 [1].
The nine major allergens
Milk, egg, fish, crustacean shellfish, tree nuts, peanuts, wheat, soybeans, and sesame. A label must name these in plain language, either within the ingredient list or in a separate 'Contains' statement (for example, 'Contains: milk, soy').
Where allergens hide in supplements
Allergens often arrive through inactive ingredients, not the headline nutrient — which is why the 'other ingredients' line deserves attention:
- Gelatin capsules can be derived from fish or shellfish.
- Lactose is a common filler (milk).
- Soy lecithin appears as an emulsifier (soy).
- Fish oil, krill oil, and marine collagen are fish or shellfish sources.
- Wheat-derived ingredients can appear in some blends.
- Tree-nut oils or flours show up in certain food-based products.
How to read a label safely
- Read it every single time. Manufacturers reformulate, and a product that was safe last year may not be today.
- Check both the ingredient list and the 'Contains' line. The allergen may be disclosed in either place.
- Understand 'may contain' / cross-contact advisories. These voluntary statements (for example, 'made in a facility that also processes tree nuts') are not required and their absence does not guarantee freedom from cross-contact.
- When unsure, contact the manufacturer using the label's contact details, and review general label-reading guidance [2].
If a reaction happens
For a known allergy, follow your action plan. A severe allergic reaction (anaphylaxis) — trouble breathing, throat tightness, swelling, faintness — is an emergency: use prescribed epinephrine if available and call 911.