Sweeteners
Aspartame
Definition
What it is
Artificial sweetener: non-caloric synthetic sweetener with contested long-term health effects; IARC classified aspartame as 'possibly carcinogenic' in 2023.
On the label
How it appears on labels
- aspartame
Regulation
Regulatory status
No bans or restrictions are recorded for this ingredient in the jurisdictions clearlabel tracks (US, EU, UK, Canada, Japan, Australia/NZ, Brazil).
Explainer
In plain language
Aspartame is an artificial sweetener roughly 200 times sweeter than table sugar, approved by the FDA in 1981 and used in thousands of sugar-free and diet products, most famously diet sodas. Chemically it is two amino acids, aspartic acid and phenylalanine, joined by a methyl ester. Because so little is needed for sweetness, it adds effectively zero calories.
Assessment
Why it is flagged
In 2023 the International Agency for Research on Cancer classified aspartame as possibly carcinogenic to humans (Group 2B), a category that signals limited evidence, not proof of harm. The same year, the WHO and FAO expert committee on additives reviewed the data and kept the acceptable daily intake unchanged, and the FDA continues to permit it. Clear Label flags aspartame because its long-term effects remain contested between major scientific bodies, and because some users track headaches or mood changes against it in their own logs. Those are correlations to test, not diagnoses. Separately, people with the genetic condition phenylketonuria cannot break down phenylalanine, which is why US products carry a phenylalanine notice.
In the aisle
Where it commonly shows up
- Diet and zero-sugar sodas
- Sugar-free gum and mints
- Light or sugar-free yogurts
- Tabletop sweetener packets
- Sugar-free gelatin and pudding mixes
- Reduced-sugar drink powders and flavored waters
Practical
Reading the label
Aspartame is usually named outright in US ingredient lists. The phrase 'Phenylketonurics: contains phenylalanine' near the ingredient list is another reliable signal that a product contains it. In the EU it can appear as E951.
Alternatives
If you want to avoid it
Some people who want fewer artificial sweeteners choose unsweetened sparkling water, or products sweetened with stevia or monk fruit, which Clear Label tracks as separate lower-severity flags. Plain water, coffee, or tea without sweetener sidesteps the question entirely.
FAQ
Common questions
Is aspartame banned anywhere?
No major market has banned aspartame as of 2026. The 2023 IARC review placed it in Group 2B, possibly carcinogenic, but regulators in the US, EU, Canada, and Australia continue to permit it with a defined acceptable daily intake.
How much aspartame do regulators consider acceptable?
The WHO and FAO expert committee sets the acceptable daily intake at 40 mg per kg of body weight per day, and the FDA uses 50. For a 70 kg adult that works out to roughly 9 to 14 cans of diet soda every day, far above typical consumption.
Why do some people avoid it anyway?
Some users report headaches, mood changes, or cravings that track with aspartame in their own food and symptom logs. The published evidence on these effects is mixed, which makes it exactly the kind of personal pattern Clear Label is built to help you test rather than assume.
Citations
Sources
Citation
Primary reference
About this page: the definition, label names, severity, and regulatory chips come from the clearlabel ingredient taxonomy, the same data the scanner uses to score products. Research summaries describe associations reported in published studies, not diagnoses; individual responses vary. Scan any product with clearlabel to see which of its ingredients carry flags.