E951 / Glazing agents, gases & sweeteners
Aspartame
Safety in brief
Safe
Recorded EatMatrix rating, not a new clinical review. The amount, your sensitivities and country rules still matter.
- Watch for
- Recorded sensitivities: Phenylketonuria (PKU) — contains phenylalanine.
- Our advice
- The human studies here do not show that aspartame inevitably harms everyone, or that it provides a health benefit on its own. People with phenylketonuria need to avoid or restrict phenylalanine under their care plan; the general-population regulatory assessment does not remove that exception.
What it is
Aspartame is a low-calorie artificial sweetener roughly 200 times sweeter than sugar, used in diet sodas, sugar-free gum, and other \"diet\" foods. In the body it breaks down into aspartic acid, phenylalanine, and a small amount of methanol, which is why products containing it must warn people with phenylketonuria (PKU) — a rare inherited disorder — that it is a source of phenylalanine. It loses sweetness at high temperatures, so it's not typically used in baking. The FDA and EFSA maintain that aspartame is safe within the acceptable daily intake, though in 2023 the WHO's cancer research arm (IARC) classified it as \"possibly carcinogenic to humans\" (Group 2B) based on limited evidence, a classification that reflects hazard, not the level of risk at typical consumption.
Also appears on labels as: Aspartame, E951, E 951, E-951, NutraSweet, Equal, Canderel, APM, Artificial sweetener Aspartame, Methyl ester of aspartyl-phenylalanine, Aspartyl-phenylalanine-1-methyl ester, Low-calorie sweetener Aspartame.
Dietary information
- Vegan
- Yes
- Halal
- Yes
- Gluten-free
- Yes
- Allergens
- Caution
Recorded ingredient information. Check the product label or certification: sources, other ingredients and cross-contact can vary.
Research & body effects
What human studies mean for E951
Blood sugar and gut bacteria: a short experiment
A 2022 randomized study assigned 120 healthy adults to two weeks of saccharin, sucralose, aspartame or stevia sachets, a glucose-vehicle control, or no supplement. Saccharin and sucralose impaired measured glucose responses compared with controls; this finding was not uniform across all four sweeteners.
This ingredient was studied, but it was not one of the two identified in the abstract as significantly impairing glucose responses. That does not prove long-term benefit or safety for every preparation.
Changes in gut bacteria are not automatically gut damage. Transferring participants’ microbes into mice supported a possible mechanism; it was not a second human trial or a validated test of your personal sensitivity.
Four sweeteners, gut microbes and glucose responses. Indexed abstract and selected publisher text read; complete methods and supplements pending. Indexed comments were identified, not fully appraised. Some authors disclose microbiome-company interests.
Weight management: a drink comparison does not isolate this additive
In the SWITCH study, 493 adults started a weight-management programme using water or non-sugar-sweetened drinks; 220 completed 104 weeks. The 2026 report found no statistically significant difference in maintained weight loss between groups. Substantial dropout limits confidence in the estimate.
The drinks predominantly used aspartame, acesulfame K and sucralose. Participants could choose and change products, so this was not a test of one isolated ingredient. Earlier reports from the same programme are not independent replications. This weight outcome does not settle every health outcome.
Related beverage trial: water versus sweetened drinks over 104 weeks. Selected main-text methods, results, limitations and declarations read; supplements not fully appraised. Funded by the American Beverage Association; some authors disclose other industry relationships.
Related whole-diet evidence: a benefit and a trade-off
The 2025 SWEET trial compared low-sugar diets that allowed or excluded products with many sweeteners after an initial weight-loss phase. The analysis of 277 adults who reached the initial loss target favoured allowing these products by about 1.6 kg at one year. The difference was not statistically significant when only completers were analysed.
About 40% of recruited adults did not complete the study. The sweetener group reported more abdominal pain, loose stools and gas. Many products and ingredients varied together: neither the weight result nor the symptoms can be attributed to this one additive.
Related whole-diet SWEET trial: weight maintenance and gut symptoms. Selected main-text methods, results, limitations and declarations read; supplements not fully appraised. EU Horizon 2020 funding; several authors disclose food-industry relationships.
EatMatrix’s reading
The human studies here do not show that aspartame inevitably harms everyone, or that it provides a health benefit on its own. People with phenylketonuria need to avoid or restrict phenylalanine under their care plan; the general-population regulatory assessment does not remove that exception.
A practical choice
Compare the whole food and your usual alternative, including free sugars, fibre and how often you eat it. Water or an unsweetened drink is a straightforward option. A sweetener name alone cannot tell you the dose in a serving or predict your personal response.
WHO’s 2023 recommendation against using non-sugar sweeteners for long-term weight control is conditional and excludes people with pre-existing diabetes. It is nutrition guidance, not a country ban or a replacement for an additive safety assessment. Read WHO’s scope and limits.
Selected sources checked . The reading scope is stated beside each source. These are selected findings, not an exhaustive clinical review or a personal diet prescription. Indexed notices were checked where accessible; missing notices do not prove that no correction or later version exists. The research does not by itself change recorded ratings or country permissions. Use the country section for the separate legal question.
Selected research on E951
How to read study types- Regulator reviewEFSA re-evaluation of aspartame-acesulfame salt
Re-checked aspartame and acesulfame K as part of this review. Confirmed aspartame’s safe daily limit of 40 mg per kg of body weight and found no safety concern at current uses for E950, E951 and E962.
- Randomized trialRelated beverage trial: water versus sweetened drinks over 104 weeks
Related mixed-beverage trial: 220 of 493 starters completed 104 weeks. Maintained weight loss did not significantly differ from water. Drinks predominantly used aspartame, acesulfame K and sucralose; the study cannot isolate one additive.
- Randomized trialRelated whole-diet SWEET trial: weight maintenance and gut symptoms
Related whole-diet trial favoured sweetener-containing products for weight maintenance in one analysis, but not the completer analysis. Dropout was high and gut symptoms were more frequent. Many ingredients varied together; no individual-additive effect was isolated.
- Randomized trialFour sweeteners, gut microbes and glucose responses
Two-week trial in 120 healthy adults: saccharin and sucralose impaired measured glucose responses; this was not uniform across all four sweeteners. Microbiome changes and mouse transfers do not establish future diabetes or a personal sensitivity test.
- Regulator reviewEFSA re-evaluation of aspartame
Aspartame is not a safety concern at current intake or at its safe daily limit of 40 mg per kg of body weight. The limit does not apply to people with PKU.
Earlier source summaries checked ; latest additions checked . See the detailed research section for what was read and the remaining limits. This is a selection of sources, not a complete literature review. Authority assessments apply to the uses and places they cover.
Health notes from our ingredient record
- Contains phenylalanine and must be avoided by people with phenylketonuria (PKU).
- In 2023, IARC classified aspartame as 'possibly carcinogenic' (Group 2B) based on limited evidence, while EFSA and the FDA maintain it is safe within the established acceptable daily intake.
Other references from our ingredient record
These links come from the original ingredient record. They are separate from the source reviews above and have not all been checked for the exact ingredient, amount consumed or claim. Dates are shown newest first.
- Scientific Opinion on the re‐evaluation of aspartame (E 951) as a food additive — EFSA Panel on Food Additives, EFSA Journal (2013). Official EFSA scientific opinion (bibliographic reference, imported 2026-10-13). It covers the additive as a group assessment and is not an individual human study; read the opinion for its findings.
Country rules
Country checks for E951
Permission depends on the market, type of food, amount and conditions. A scientific opinion or an E-number alone does not establish a legal use. These checks are separate from the stored EatMatrix rating.
Compare all eight markets and their sources
| Market | What is checked |
|---|---|
| European Union | Regulation (EC) 1333/2008, Annex II Part B, version , contains the exact code E951: Aspartame. Listing alone does not allow every food use. Part E food categories, limits, specifications and applicable later acts still need a product-specific check. Source read: . |
| Great Britain | The FSA register record for E951 (Aspartame) lists “Authorised” in England, Scotland and Wales. Register updated: 01 April 2025; record checked: . Food-specific conditions and specifications still need a separate legal check. |
| United States | Selected US conditions for Aspartame Official federal text current through ; read . Food uses, limits and exceptionsNamed preparation and use conditions The specified sweetener/flavour enhancer may be used under good manufacturing practice where food standards permit it. Foods containing it must prominently state “PHENYLKETONURICS: CONTAINS PHENYLALANINE”. Baked goods/mixes have a 0.5% maximum before baking with other ingredients to ensure sweetening functionality; table-use sugar substitutes carry instructions not to use in cooking or baking. Those product rules are different and must not be swapped. EatMatrix’s reading: a legal use condition answers where and how an ingredient may be used. It is not a test of your product, a personal safe intake or a claim that the ingredient benefits your body. Match the named substance, food and amount. Other federal provisions, food standards, state rules and later changes may also apply; this is a selected source review, not a complete product-compliance decision. |
| Northern Ireland | Review pending. Check the applicable EU rules and territory arrangements; the GB register alone does not establish this status. FSA guidance is a starting source, not a verified permission for this entry. |
| Canada | Named food-use records located. Health Canada lists the preparations below for specified foods and purposes. This is conditional permission for those uses, not approval of every product or a personal safety verdict. Only the named records and conditions below were located. Exact composition and specifications still need matching. Source tables captured . List publication dates are shown separately. Good Manufacturing Practice (GMP) is a condition of use, not an unlimited amount or a recommended intake. Food and Drug Regulations B.16.003 requires the listed source, purpose, amount and other conditions to match. The official consolidation read was current to 21 September 2026; product specifications and applicable later changes still need checking. Read 11 listed food-use conditionsAspartameHealth Canada: List of Permitted Sweeteners. List published ; item A.3.
EatMatrix reading: match the exact preparation and food first. A manufacturing limit is not an acceptable daily intake (ADI). A label without the amount cannot establish exposure, and an unlisted name here does not establish a ban. |
| Australia | Review pending. Food Standards Code permissions and conditions need an additive-specific check. FSANZ food-additive rules is a starting source, not a verified permission for this entry. |
| New Zealand | Review pending. Food Standards Code permissions and conditions need an additive-specific check. FSANZ food-additive rules is a starting source, not a verified permission for this entry. |
| Japan | Review pending. The relevant list, identity and use standards need an additive-specific check. CAA food-additive lists is a starting source, not a verified permission for this entry. |
Sources & review status
Check what each source covers: an authority’s conclusion, a research finding and a country’s legal permission answer different questions.
What this guide covers
- Selected research
- 5 source summaries, with publication dates and study types. Several publications may describe the same study population.
- Official assessment sources
- Commission-listed EFSA references for E951. Bibliographic identity checked; latest findings and current use rules need separate review.
- Original ingredient record
- 1 research link; newest recorded date: . Sources added separately to this guide are not included in this count.
This guide brings together our ingredient record and the dated sources shown here. Missing information describes a gap in this guide; it does not mean an ingredient is untested, safe or harmful. This is not a complete review of every study, preparation or current country rule. The amount in a product and how it is used still matter.
How to read the ratings, research and country checksAgency labels recorded by EatMatrix
These are imported database classifications, not verified current statements from each authority. Use the dated official sources below for their actual scope and conclusions.
| Authority | Database label |
|---|---|
| FDA | Safe |
| WHO | Safe |
| EFSA | Safe |
| FSANZ | Safe |
| Japan | Safe |
| UK FSA | Safe |
Official assessment sources for E951
The European Commission’s re-evaluation table lists official EFSA documents for this additive. Their identifiers and subjects were checked against publisher bibliographic records. A missing research link in the EatMatrix database does not mean the additive has never been assessed.
Name in the Commission table: Aspartame.
- Scientific Opinion on the re‐evaluation of aspartame (E 951) as a food additive
EFSA scientific opinion. Publication month: .
These are assessment references, including historical or group assessments. They do not establish the latest scientific conclusion, a human health benefit or risk, or current permission to use the additive in a particular food. Later assessments, corrections and food-use conditions need separate review. The recorded EatMatrix rating above is unchanged.
European Commission re-evaluation table, status as of . EatMatrix checked this bibliography on .
Database updated: . What does an E number mean on a food label?
Common questions
Frequently asked questions
What is EatMatrix's recorded rating for E951?
The recorded EatMatrix rating for E951 (Aspartame) is “Safe”. It is calculated from labels stored in our ingredient database. These labels are not verified current regulator decisions or country permissions. A database update date is not a scientific review date.
Is E951 vegan, halal or gluten-free?
According to our ingredient data for Aspartame — vegan: yes, vegetarian: yes, halal: yes, kosher: yes, gluten-free: yes, dairy-free: yes. Manufacturing sources can vary between products; check the label if it matters to you.
What is E951 and why is it used?
Aspartame is a low-calorie artificial sweetener roughly 200 times sweeter than sugar, used in diet sodas, sugar-free gum, and other \"diet\" foods. In the body it breaks down into aspartic acid, phenylalanine, and a small amount of methanol, which is why products containing it must warn people with phenylketonuria (PKU) — a rare inherited disorder — that it is a source of phenylalanine. It loses sweetness at high temperatures, so it's not typically used in baking. The FDA and EFSA maintain that aspartame is safe within the acceptable daily intake, though in 2023 the WHO's cancer research arm (IARC) classified it as \"possibly carcinogenic to humans\" (Group 2B) based on limited evidence, a classification that reflects hazard, not the level of risk at typical consumption.
Does E951 contain allergens?
No known allergens are recorded for Aspartame, with a caution: Phenylketonuria (PKU) — contains phenylalanine.
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This page shows information and classifications recorded in our ingredient database. Current scientific and market-specific verification remains pending as described above. It is general information, not medical advice.