U.S. · Food additives · 21 CFR 172.804
Aspartame in food.
21 CFR 172.804 permits aspartame as a sweetening agent and flavor enhancer, caps it at 0.5 percent in baked goods and requires a phenylketonuria statement on labels.
21 CFR 172.804 says aspartame may be safely used in food in accordance with good manufacturing practice as a sweetening agent and a flavor enhancer in foods where a standard of identity does not preclude it. Baked goods and baking mixes are capped at 0.5 percent by weight, L-leucine as a lubricant in sugar substitute tablets for hot beverages is capped at 3.5 percent of tablet weight, and any food containing aspartame must bear the statement PHENYLKETONURICS: CONTAINS PHENYLALANINE.
Check weights against the numeric limits
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What 21 CFR 172.804 says
Section 172.804 opens with the core permission: "The food additive aspartame may be safely used in food in accordance with good manufacturing practice as a sweetening agent and a flavor enhancer in foods for which standards of identity established under section 401 of the Federal Food, Drug, and Cosmetic Act do not preclude such use under the following conditions." The conditions then follow in lettered paragraphs (a) to (e). The text reproduced here is the eCFR version current through October 29, 2026; the section history shows it was issued at 39 FR 27319 on July 26, 1974.
Identity and specifications: (a) and (b)
- (a) Aspartame is the chemical 1-methyl N-L-alpha-aspartyl-L-phenylalanine (C14H18N2O5).
- (b) The additive meets the specifications of the Food Chemicals Codex, 7th ed. (2010), pages 73 to 74, which the section incorporates by reference. Copies may be obtained from the United States Pharmacopeial Convention and examined at the FDA Dockets Management Staff or the National Archives.
Numeric limits: paragraph (c)
| Use | Limit in the section | Paragraph |
|---|---|---|
| Sugar substitute tablets for sweetening hot beverages, including coffee and tea | L-leucine may be used as a lubricant at a level not to exceed 3.5 percent of the weight of the tablet | (c)(1) |
| Baked goods and baking mixes | Aspartame not to exceed 0.5 percent by weight of ready-to-bake products or of finished formulations prior to baking | (c)(2) |
For baked goods the section adds two more points. Generally recognized as safe (GRAS) ingredients, or food additives approved for use in baked goods, "shall be used in combination with aspartame to ensure its functionality as a sweetener in the final baked product." And the level of aspartame in those products is determined by an analytical method entitled "Analytical Method for the Determination of Aspartame and Diketopiperazine in Baked Goods and Baking Mixes," dated October 8, 1992, developed by the Nutrasweet Co. The section says copies are available from the FDA Office of Food Additive Safety.
Other food categories are not given a numeric ceiling in 172.804. They fall under the general permission for good manufacturing practice, subject to labeling.
Labeling: paragraph (d)
Paragraph (d) begins "To assure safe use of the additive, in addition to the other information required by the Act" and then sets four labeling requirements:
- (d)(1) The principal display panel of any intermediate mix of the additive for manufacturing purposes shall bear a statement of the concentration of the additive in it.
- (d)(2) The label of any food containing the additive shall bear, on the principal display panel or the information panel, the statement PHENYLKETONURICS: CONTAINS PHENYLALANINE. It must appear prominently and conspicuously as compared to other words, statements, designs or devices, in bold type and on a clear contrasting background, so that it is likely to be read and understood by the ordinary individual under customary conditions of purchase and use.
- (d)(3) When aspartame is used in a sugar substitute for table use, the label shall bear instructions not to use it in cooking or baking.
- (d)(4) Packages of the dry, free-flowing additive shall prominently display the sweetening equivalence in teaspoons of sugar.
Paragraph (e) adds that if the food "purports to be or is represented for special dietary uses," it shall be labeled in compliance with part 105 of Title 21.
Worked example
A bakery tests a muffin batter with 4 grams of aspartame in 1,000 grams of finished formulation before baking. That is 0.4 percent by weight, under the 0.5 percent ceiling in (c)(2). At 6 grams the ratio becomes 0.6 percent, over the ceiling. A tablet maker using 3 grams of L-leucine in a 100 gram batch of tablets is at 3 percent, within the 3.5 percent figure in (c)(1). Whatever the numbers, the finished package would carry the (d)(2) phenylalanine statement. The checker above does the two divisions for you and nothing else.
What the section does not say
It does not discuss health outcomes, acceptable daily intake or any consumer guidance, and this page does not either. It does not set a ceiling for beverages or other categories, and it does not decide whether a product claim such as "sugar free" is allowed, which is a separate labeling rule. People with phenylketonuria follow medical advice from their clinicians; the labeling statement exists so they can identify products containing phenylalanine.
Sources
Sources opened and read November 2, 2026.
Frequently asked questions
What does 21 CFR 172.804 permit?
Aspartame as a sweetening agent and a flavor enhancer in food, in accordance with good manufacturing practice, where a standard of identity does not preclude it.
What is the aspartame limit in baked goods?
Not to exceed 0.5 percent by weight of ready-to-bake products or of finished formulations prior to baking (172.804(c)(2)).
What statement must foods with aspartame carry?
PHENYLKETONURICS: CONTAINS PHENYLALANINE, on the principal display panel or the information panel, prominently and conspicuously and in bold type on a clear contrasting background (172.804(d)(2)).
Can a tabletop aspartame sweetener say to use it in cooking?
No. When used in a sugar substitute for table use, the label must bear instructions not to use it in cooking or baking (172.804(d)(3)).
What is the L-leucine limit in aspartame tablets?
L-leucine used as a lubricant in sugar substitute tablets for hot beverages must not exceed 3.5 percent of the tablet weight (172.804(c)(1)).
What specifications must aspartame meet?
Those of the Food Chemicals Codex, 7th ed. (2010), pages 73 to 74, incorporated by reference in 172.804(b).
Is this page medical advice about aspartame?
No. It reports the text of the regulation only. Ask a clinician about personal health questions.
Not legal or compliance advice
This page is general information drawn from the sources listed, not legal, tax or compliance advice, and it is not run by any government agency. Rules, forms and dates change and your agency, base jurisdiction or enforcement officer decides your case, so confirm with the office named on this page before you rely on it. Everything runs in your browser; nothing you enter is sent anywhere.