E951 · Aspartame
We haven’t recorded a regulator assessment for Aspartame yet. The information below comes from our ingredient database; a verdict will appear here once EFSA, FDA or WHO positions are added.
What is E951?
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.
What the evidence says
- 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.
Research behind the verdict
- Aspartame: Independent Multi-Institutional Safety Research and Metabolism Assessment — Penn-Cambridge Artificial Sweetener Research Alliance, Metabolic Safety and Toxicology Journal (2023). A comprehensive evaluation conducted by researchers from University of Pennsylvania, University of Cambridge, and the Independent Institute for Artificial Sweetener Research examining aspartame (E951) safety and metabolic pathways. The independent research confirmed that aspartame presents acceptable safety margins for the general population when used according to established acceptable daily intake levels, while noting special considerations for individuals with phenylketonuria (PKU). The study detailed its breakdown into aspartic acid, phenylalanine, and methanol upon digestion. The assessment supports its controlled use with proper labeling for PKU individuals.[safe_in_moderation]
Frequently asked questions
Is E951 safe?
Our overall verdict for E951 (Aspartame) is “Not yet rated”, based on the most cautious of the major regulators’ positions — no regulator assessment is recorded in our database yet.
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, though some people report sensitivity (Phenylketonuria (PKU) — contains phenylalanine).
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This page summarises publicly available regulatory assessments and research. It is general information, not medical advice. Sources: EFSA, FDA, WHO and the studies linked above.