21 CFR 101.4 is the core FDA regulation governing the ingredient list on food and dietary supplement labels. It establishes the requirement to declare ingredients by common or usual name, in descending order of predominance by weight, and specifies how compound ingredients, spices, flavors, and coloring agents must be handled.
Ingredient list violations are among the most common findings in FDA warning letters and import alerts. Errors frequently arise from sub-ingredient disclosure, allergen-in-ingredient issues, and incorrect name use for standardized ingredients.
The Basic Rule: Common or Usual Name, Descending by Weight
Under 21 CFR 101.4(a)(1), ingredients must be:
Listed by common or usual name — not trade names, supplier codes, or chemical IUPAC names (unless those are the common or usual names)
In descending order of predominance by weight — the heaviest ingredient first, the lightest last
On the information panel or principal display panel — in accordance with 21 CFR 101.2
Weight is determined at the time the ingredient is added during manufacturing — not after cooking, processing, or moisture changes that affect the finished product. This distinction matters for products where moisture is driven off during processing (e.g., baked goods, dried snacks).
The 2% Threshold Rule
Under 21 CFR 101.4(a)(2), ingredients present at 2% or less by weight may be listed in any order, provided they appear at the end of the ingredient statement following a quantifying statement such as:
"Contains 2% or less of: ____"
"Less than 2% of: ____"
This allows brands to group minor ingredients without strictly ordering them by weight. However, no ingredient listed after the threshold statement may be present in an amount greater than the stated threshold.
Multi-Component (Compound) Ingredients and Sub-Ingredients
When a food contains a multi-component ingredient — an ingredient that is itself made from multiple sub-ingredients (e.g., "chocolate chips" or "seasoning blend") — the sub-ingredients must be disclosed in one of two ways under 21 CFR 101.4(b):
Parenthetical declaration: List the compound ingredient by name, followed by its sub-ingredients in parentheses: "Chocolate Chips (Sugar, Chocolate Liquor, Cocoa Butter, Vanilla Extract)"
Incorporation into the main ingredient list: Disassemble the compound ingredient entirely and list each sub-ingredient individually in its appropriate place in the overall descending-weight order, without listing the compound ingredient itself
The parenthetical method is most common. The key compliance trap: if a sub-ingredient contains a major food allergen, that allergen must appear in the parenthetical — it cannot be hidden within a compound ingredient name.
Spices, Flavors, and Colors
Spices
Under 21 CFR 101.4(b)(1), spices may be declared collectively as "spices" rather than by individual name. However, if a spice is also an allergen source (e.g., sesame), it must be individually declared for allergen compliance under FALCPA/FASTER Act.
Artificial and Natural Flavors
Artificial flavors must be declared as "artificial flavor," "artificial flavoring," or the specific flavor name
Natural flavors may be declared as "natural flavor" or "natural flavoring" under 21 CFR 101.22 — the specific characterizing flavor source need not be disclosed unless it is an allergen
If both natural and artificial flavors are present, the label may state "natural and artificial flavor"
Post-FASTER Act sesame requirement: If a natural flavor blend contains sesame, "sesame" must be separately declared as an allergen — "natural flavor (sesame)" or in a "Contains: Sesame" statement.
Color Additives
Under 21 CFR 101.4(b)(4):
Certified color additives (FD&C dyes) must be listed by their specific name: "FD&C Red No. 40," "FD&C Blue No. 1," etc. — they cannot be grouped under "artificial color"
Exempt color additives (natural colorings derived from vegetable, animal, or mineral sources) may be declared by specific name or as "artificial color," though using the specific name is preferred
Colors that are also ingredients (e.g., beet juice used for color) may be listed as "beet juice (for color)"
Ingredient List for Dietary Supplements
Under 21 CFR 101.4(g), dietary supplements have a modified ingredient list requirement:
Dietary ingredients listed in the Supplement Facts panel under 21 CFR 101.36 need not be repeated in a separate ingredient list
Other ingredients — those that are not dietary ingredients but are present in the supplement (e.g., binders, fillers, coatings, excipients, capsule materials) — must be declared in a separate ingredient list on the label
The "Other Ingredients" list typically appears immediately below the Supplement Facts panel and includes items like: microcrystalline cellulose, magnesium stearate, silicon dioxide, gelatin (capsule), rice flour
Placement and Prominence Requirements
Under 21 CFR 101.2 and 21 CFR 101.4:
The ingredient list must appear on the information panel (the panel immediately to the right of the principal display panel) or on the principal display panel itself
The ingredient list must appear as a continuous block of text — it cannot be split across multiple panels
The heading "Ingredients:" must precede the list
Type size must be no smaller than the minimum type size required for the net quantity declaration under 21 CFR 101.7, with a minimum of 1/16 inch
Common Ingredient List Violations
FDA warning letters and import refusals frequently cite:
Allergen in sub-ingredient not disclosed — a compound ingredient contains milk, wheat, or sesame that does not appear in the main ingredient list or a "Contains" statement
Ingredients out of order — incorrect descending-by-weight order, often from inaccurate formulation records
Trade names instead of common names — using a supplier's branded ingredient name instead of the regulatory common name
Missing "Other Ingredients" on supplements — excipients omitted from the label
Natural flavor containing sesame not declared — post-FASTER Act (January 1, 2023) violation
Certified color not declared by specific name — listing "artificial color" instead of "FD&C Red No. 40"
Compound ingredient sub-ingredients not parenthetically disclosed
How Truli Helps with Ingredient List Compliance
Allergen-in-ingredient detection: Truli scans formulation ingredient trees for allergens embedded in compound or flavoring ingredients not declared on the finished product label
Sub-ingredient disclosure audit: Truli checks that parenthetical sub-ingredient declarations are complete
Color additive name verification: Truli flags collective "artificial color" declarations where certified color names are required
Supplement "Other Ingredients" check: Truli identifies excipients typically present in supplement forms that should appear in the Other Ingredients declaration
Related Regulations
21 CFR Part 101 — FDA food labeling overview
FALCPA and FASTER Act — Allergen declaration requirements that interact directly with ingredient list rules
21 CFR 101.36 — Supplement Facts Panel — How dietary supplement ingredient declaration relates to the ingredient list
Frequently Asked Questions
Does "natural flavor" need to disclose the specific flavor source?
Generally no — 21 CFR 101.22 permits grouping under "natural flavor" without naming the specific source. The exception is allergens: if the natural flavor contains milk, wheat, soy, sesame, or another major allergen, the allergen source must be disclosed.
Can I list water as an ingredient?
Water added to a food must be listed in the ingredient list if it is a significant component of the finished product. Water used only as a processing aid that is evaporated off during manufacturing may be omitted under 21 CFR 101.100. Incidental additives present at insignificant levels with no technical function in the finished food may also be omitted.
If I reformulate and change ingredient suppliers, do I need to update the ingredient list?
Yes, if the new supplier's ingredient has different sub-ingredients or if the allergen profile changes. If a new natural flavor supplier uses sesame and the prior supplier did not, the label must be updated immediately to add sesame allergen disclosure — selling existing labeled inventory may be acceptable for a transition period, but any new production runs must use compliant labels.
A note from Truli: Truli is not a law firm, and this article does not constitute or contain legal advice or create an attorney-client relationship. When determining your obligations and compliance with respect to relevant laws and regulations, you should consult a licensed attorney.
Last updated: April 2026. Reflects 21 CFR 101.4 as of April 2026. Truli monitors FDA guidance on ingredient labeling for food and supplement brands. Book a demo to see how.
