Aspartame

Regulators consider aspartame safe within recommended limits. In July 2023 the WHO’s JECFA expert committee reviewed the evidence and reaffirmed the acceptable daily intake of 0–40 mg per kg of body weight per day, finding no sufficient reason to change it. The UK NHS likewise lists aspartame among approved sweeteners that pass a rigorous safety assessment. The main exception is people with the genetic condition PKU (see below).

In July 2023 the WHO’s cancer agency IARC classified aspartame as “possibly carcinogenic to humans” (Group 2B) based on limited evidence, chiefly for liver cancer. Group 2B is a hazard identification meaning the evidence is not strong — the same category as aloe vera extract — and says nothing about how much exposure would pose a real-world risk. On the risk question, JECFA kept the safe intake unchanged, and Cancer Research UK states there is no strong evidence aspartame causes cancer at normal consumption levels.

JECFA’s acceptable daily intake is 0–40 mg per kg of body weight per day, reaffirmed in July 2023. To put that in context, WHO estimates a 70 kg adult would need to drink more than about 9 to 14 cans of a diet soft drink every day to exceed the limit, assuming no other aspartame in the diet. Typical consumption is well below this threshold.

People with phenylketonuria (PKU), a rare inherited condition, must avoid or strictly limit aspartame because it contains phenylalanine, which their bodies cannot properly break down. For this reason products containing aspartame carry the E number E951 plus a mandatory warning that they contain a source of phenylalanine. For everyone else, phenylalanine from aspartame is not a concern at normal intakes.

Aspartame is roughly 200 times sweeter than sugar and adds virtually no calories, so replacing sugar with it can cut sugar and calorie intake in the short term. However, in 2023 the WHO advised against using non-sugar sweeteners (including aspartame) as a long-term strategy for weight control, saying the evidence shows no lasting benefit for reducing body fat and pointing to possible long-term risks. So it is not a proven route to weight loss, though it remains safe within the acceptable daily intake.

Health authorities consider aspartame acceptable for the general population, including during pregnancy, when consumed within the acceptable daily intake (JECFA’s 40 mg/kg/day, reaffirmed in 2023); the NHS lists approved sweeteners as a safe alternative to sugar. The important exception is a pregnant person who has PKU or raised blood phenylalanine, who must avoid aspartame. As with any diet question in pregnancy, moderation is sensible and a midwife or doctor can advise on individual circumstances.

Yes — it contains no animal-derived material. It is a synthetic dipeptide built from two amino acids. The same applies to a vegetarian diet.

Yes — the additive itself contains no gluten. A gluten-free claim belongs to the finished product, though — check the pack, not the additive.

It is a synthetic dipeptide built from two amino acids and contains no animal-derived material, so the additive itself is not inherently non-halal. Certification applies to a finished product rather than to an additive, so a halal certification mark on the pack is the authoritative signal.

Aspartame releases phenylalanine when digested, so people with phenylketonuria (PKU) must avoid it — EU law requires a label warning for exactly that reason. For everyone else EFSA re-confirmed an acceptable daily intake of 40 mg per kg of body weight. In 2023 the IARC classified aspartame as "possibly carcinogenic" (Group 2B) while the JECFA kept the same intake limit, so the practical guidance did not change.