An E number is an EU code for a food additive that has been assessed for safety and authorized for specific uses: EFSA does the science, and the European Commission with the member states makes the decision. The FDA runs a parallel system in the United States built on premarket approval, with substances generally recognized as safe and prior-sanctioned substances as the exceptions. Neither regulator treats "additive" as a synonym for "harmful", and both have restricted or removed specific substances when the evidence changed.
This article is educational information, not medical advice.
What does an E number actually mean?
EFSA defines food additives as substances added to food and drinks to maintain or improve their safety, freshness, taste, texture or appearance. In the EU every authorized additive receives an E number, and more than 300 substances are authorized. The legal definition in Regulation (EC) No 1333/2008 is any substance not normally consumed as a food in itself, intentionally added for a technological purpose, that becomes a component of the food.
The UK's food additives guidance, which inherits the E number system, states the three conditions for the code: the additive has been tested and proved to be safe for its intended use, there is a justifiable technological need to use it, and its use does not mislead the consumer. It groups the additives shoppers meet most often as antioxidants, colors, emulsifiers, stabilizers, gelling agents and thickeners, preservatives, and sweeteners.
On a label the additive appears by function first, followed by its name or E number. "Preservative: potassium sorbate" and "preservative: E202" describe the same ingredient, so an E number on a label is not a signal of anything beyond authorization.
How does EFSA decide an additive is safe?
The central tool is the acceptable daily intake, which EFSA's glossary defines as an estimate of the amount of a substance in food or drinking water that can be consumed daily over a lifetime without presenting an appreciable risk to health, expressed in milligrams per kilogram of body weight per day. Approval is for specific uses at specific levels, and EFSA compares estimated exposure against the ADI for different population groups.
The assessment does not stop at approval. Under Regulation (EU) No 257/2010, EFSA is re-evaluating every additive authorized before 20 January 2009; the original 2020 deadline was extended for workload, and more than 70% of the 315 additives in scope have been re-evaluated. Where toxicological data are limited, EFSA can lower an ADI, and where exposure estimates suggest a population group may exceed it, the Commission can change the conditions of use.
Sweeteners show the program in motion. EFSA's sweeteners page lists 19 authorized sweeteners, nine with completed re-evaluations and ten ongoing: acesulfame K was found safe at authorized uses in 2025, saccharin's safety threshold was increased in 2024, and on 17 February 2026 EFSA found sucralose safe when used as currently authorized while declining to confirm the safety of extending its use.
How does the FDA regulate additives differently?
The FDA's definition of a food additive is any substance whose intended use results, or may reasonably be expected to result, in its becoming a component of or otherwise affecting the characteristic of any food. Such substances require premarket approval unless they fall into two categories: substances generally recognized as safe, and prior-sanctioned substances, meaning uses covered by a no-objection letter from FDA or USDA issued before 6 September 1958.
GRAS rests on sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act. A substance qualifies when it is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, either through scientific evidence or, for substances used before 1958, through a history of common use in food. A GRAS conclusion bypasses the formal petition process; companies can notify the FDA under a voluntary program and receive a letter stating whether the agency has questions.
Color additives are handled separately and always need premarket approval. The FDA's color additive Q&A distinguishes certified colors, the synthetic dyes such as FD&C Blue No. 1, Red No. 40 and Yellow No. 5, from colors exempt from certification, which come from sources such as vegetables, minerals and animals, for example annatto extract, dehydrated beets and caramel. Nine certified color additives are approved for food, and each batch of a certified color is analyzed by the FDA against its specifications before it can be used.
| European Union | United States | |
|---|---|---|
| Who assesses | EFSA | FDA |
| Who authorizes | European Commission and member states | FDA |
| Code on the label | E number or name, after the function | Name; certified colors carry FD&C numbers |
| Route without a full approval | None; all additives are authorized substances | GRAS or prior-sanctioned status |
| Systematic re-evaluation | Regulation (EU) No 257/2010, additives approved before 2009 | No equivalent program described on the FDA pages cited here |
| Synthetic colors | Authorized per use with ADIs | Nine approved for food, certified batch by batch |
What happened with titanium dioxide, aspartame and Red No. 3?
These three cases show how the systems behave when evidence changes, and they are not all the same story.
Titanium dioxide (E171) is the case of an assessment being withdrawn. On 6 May 2021 EFSA concluded that it could no longer be considered safe as a food additive, because the panel could not exclude a genotoxicity concern after consumption of the particles, which can accumulate in the body. E171 contains up to 50% particles below 100 nanometers, and because no safe level could be established, no ADI could be set.
Aspartame (E951) is the case of two different questions being asked. EFSA's 2013 re-evaluation found aspartame and its breakdown products, phenylalanine, methanol and aspartic acid, safe at current exposure levels, with an ADI of 40 mg per kg of body weight per day that does not apply to people with phenylketonuria. On 14 July 2023 IARC classified aspartame as possibly carcinogenic to humans, Group 2B, on limited evidence, while JECFA kept the ADI at 0 to 40 mg per kg. WHO's example: a 70 kg adult drinking cans containing 200 to 300 mg each would need more than 9 to 14 cans a day to exceed the ADI. As IARC explains, its classification is hazard identification, whether a substance can cause cancer, and JECFA's is risk assessment at actual consumption.
Red No. 3 is the case of a legal rule rather than a new risk finding. On 15 January 2025 the FDA revoked authorization for FD&C Red No. 3 in food and ingested drugs under the Delaney Clause, which prohibits authorizing a color additive found to induce cancer in humans or animals. The FDA stated at the same time that the way the dye causes cancer in male rats does not occur in humans and that human exposure is typically far lower. Food makers have until 15 January 2027 and drug makers until 18 January 2028 to comply.
Which additives carry a warning label in the EU?
Six synthetic colors. Article 24 and Annex V of Regulation (EC) No 1333/2008 require foods containing Sunset Yellow FCF (E110), Quinoline Yellow (E104), Carmoisine (E122), Allura Red (E129), Tartrazine (E102) or Ponceau 4R (E124) to carry the statement "may have an adverse effect on activity and attention in children". The UK guidance lists the same six and the same wording.
The warning is a labeling rule, not a ban. The six remain authorized, EFSA has re-evaluated all previously authorized food colors, and for Sunset Yellow it refined the exposure assessment and reconsidered the temporary ADI in 2014. A product that carries the warning is telling you which colors it contains; a product without it may still contain other authorized colors.
How should you read an additive claim in an app or an article?
Ask five questions. Which regulator or body made the finding, and is it a hazard classification like IARC's or a risk assessment with an ADI like EFSA's or JECFA's? What intake does the finding assume, and how does that compare with a realistic serving? Is the finding about a specific use, such as E171 in food, or about the substance in every form? When was it published, given that EFSA re-evaluates continuously and the FDA changed Red No. 3 in 2025? And does the claim link to the opinion, so you can read it yourself?
That last question is why we built QScan to explain every deduction and cite each one to EFSA, IARC, FDA or peer reviewed research. A number without a source is an opinion; a number with one is a starting point.
Frequently asked questions
Are E numbers bad for you?
An E number only tells you an additive is authorized in the EU after a safety assessment, with conditions of use and, where data allow, an acceptable daily intake.
More than 300 substances carry one, from ascorbic acid to synthetic colors.
Individual additives have been restricted when evidence changed, such as titanium dioxide in 2021, so judge the substance and the dose, not the code.
What is the difference between IARC and EFSA saying something is safe?
IARC classifies hazard: whether a substance can cause cancer under some conditions, which is why aspartame is Group 2B on limited evidence.
EFSA and JECFA assess risk at actual intake and set an ADI, which for aspartame is 40 mg per kg of body weight per day.
Both statements can be true at once about the same substance.
Does the FDA test every food additive before it is sold?
Food additives need premarket approval, but substances generally recognized as safe by qualified experts, and uses sanctioned before 6 September 1958, do not go through that petition.
GRAS notification to the FDA is voluntary.
Color additives are stricter: all need approval, and each batch of the nine certified synthetic colors approved for food is analyzed by the FDA before use.
Why was Red No. 3 banned if the FDA says it does not cause cancer in humans?
Because the Delaney Clause prohibits authorizing any color additive found to induce cancer in humans or animals, and the dye did so in male rats.
The FDA revoked the authorization on 15 January 2025 while stating that the rat mechanism does not occur in humans.
Compliance deadlines are 15 January 2027 for food and 18 January 2028 for ingested drugs.