Aspartame

Additive · E 951

Aspartame is a sweetener used in diet drinks, gum and other foods. It is about 200 times sweeter than sugar, so only small amounts are needed. Digestion breaks it into two amino acids, including phenylalanine, and a small amount of methanol.

Also known as

aspartame · E 951 · INS 951 · aspartyl phenylalanine methyl ester · L-aspartyl-L-phenylalanine methyl ester

Why PRūF tracks it

Aspartame requires avoidance or restriction for people with PKU, while limited cancer associations and experimental findings leave uncertainty about long-term effects without establishing that ordinary dietary exposure causes those harms.

Read the research

Aspartame provides sweetness with little energy because only small amounts are needed. Its phenylalanine content is important for people with phenylketonuria, or PKU, who should avoid or restrict it as part of their prescribed diet. Cancer evidence remains unsettled. IARC classified aspartame as possibly carcinogenic based on limited evidence, especially for liver cancer; this describes a possible hazard and does not show the risk from a serving.

JECFA retained a daily intake benchmark of 40 milligrams per kilogram of body weight, while FDA uses 50. A newer US cohort reported higher cancer incidence among consumers without a clear dose–response pattern, while a separate long-running study found no overall breast-cancer association. These observational findings cannot establish causation. Recent animal and cell studies raise questions about inflammation, gut-barrier function and cardiovascular effects, but exposure and model limitations prevent direct translation to ordinary food consumption.

Human glucose and insulin trials have generally been reassuring for the measured outcomes, although long-term evidence remains limited. Rhode Island excludes artificial sweeteners from specified school foods under nutrition standards, and Louisiana has enacted a future school-food restriction.

Research reviewed on September 5, 2026 · 12 sources