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Is aspartame safe? What IARC, WHO and the FDA concluded.

Updated

What aspartame is, what the IARC 2023 “possibly carcinogenic” rating means next to the unchanged WHO and FDA intake limits, how the other artificial sweeteners compare, and which catalog products list aspartame or other artificial sweeteners.

Quick answer

Aspartame is an artificial sweetener found in diet soda, sugar-free gum and some yogurts. In July 2023 IARC classified it as “possibly carcinogenic to humans” (Group 2B) based on limited evidence, while the WHO and FAO’s JECFA kept its acceptable daily intake at 40 mg per kg of body weight. The FDA’s limit is 50 mg per kg and it says it has no safety concerns under approved conditions. People with PKU must avoid it.

IARC (2023)
Group 2B, possibly carcinogenic
JECFA ADI
40 mg/kg body weight
FDA ADI
50 mg/kg body weight
Must avoid
People with PKU

Your avoid list

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01 · A closer look

What the 2023 IARC and JECFA reviews found.

On July 14, 2023 IARC classified aspartame in Group 2B, “possibly carcinogenic to humans”, citing limited evidence mainly for liver cancer in humans, with limited evidence in animals. That rating reflects how strong the evidence is that a hazard exists, not the risk at ordinary intake. The same day JECFA reaffirmed an acceptable daily intake of 0 to 40 mg per kg of body weight, found the human cancer evidence unconvincing, and said safety is not a major concern at commonly used doses. WHO notes roughly 9 to 14 cans of diet soft drink a day for a 70 kg adult would be needed to exceed it, with no other sources.

WHO: aspartame hazard and risk assessment results released (July 14, 2023)

02 · A closer look

What the FDA says.

The FDA lists acceptable daily intakes of 50 mg per kg of body weight for aspartame, 5 for sucralose, 15 for saccharin and 15 for acesulfame potassium, and says its scientists have no safety concerns when aspartame is used under approved conditions. It disagrees with IARC’s classification, and notes people with phenylketonuria (PKU) should avoid or restrict aspartame.

FDA: aspartame and other sweeteners in food (current as of Feb 27, 2025)

03 · A closer look

Aspartame names on labels.

Look for aspartame, NutraSweet, Equal or E951, and a “Phenylketonurics: contains phenylalanine” statement. Other artificial sweeteners this checker flags are sucralose (Splenda, E955), saccharin (Sweet’N Low, E954), acesulfame potassium (Ace-K, E950), neotame (E961) and advantame (E969). Stevia, monk fruit, allulose and sugar alcohols are not flagged. The catalog products below list at least one flagged sweetener on their recorded label.

04 · A closer look

Aspartame vs sucralose.

Both are FDA-approved, with different intake limits and chemistry. The detailed side-by-side table is on the artificial sweeteners additive guide linked below.

05 · A closer look

How to avoid them.

Read the ingredient list, not the front-of-pack claim: “zero sugar” and “sugar free” products usually contain at least one. Choose products sweetened with sugar, honey, maple syrup or fruit, or with a plant-based sweetener if you accept those. Whether to avoid any sweetener is your call; this page is a label reference.

The short answer

Our picks for aspartame and artificial sweeteners

No pick yetEvery scored aspartame and artificial sweeteners label lists at least one of the groups we check, so nothing here earns a pick.

Clear noAtkins Stone Fired Three Meat Pepperoni, Italian Sausage & Bacon with a Blend of Three Cheeses Pizza (lists seed oils, artificial sweeteners and artificial preservatives), Signature Select Hazelnut Flavored Coffee Creamer (lists seed oils, artificial sweeteners and corn syrups), Nissin Sweet Chili Cup Noodles (lists seed oils, artificial sweeteners and artificial preservatives), plus 21 more with a listed group.

Ranked from 24 of 24 products with current labels. Every product is in the table below; a score reflects labels and claims, not nutrition, allergies or safety.

Compare the recorded labels

Find the ingredients that matter to you.

24 of 24 products

“No …” columns: None found on the label · Listed on the label · Unknown. Diet fit: Fits · Doesn’t fit · Unknown (rules; not medical advice). Claims: verified · not established. Default: most check marks first; not a health score.

Compare product claims and recorded ingredients. Click a column heading to sort.
Buy
63 / 1008 of 9 groups clear · no organic claimProduct details →3
63 / 1008 of 9 groups clear · no organic claimFind where to buy ↗Product details →3
63 / 1008 of 9 groups clear · no organic claimProduct details →3
63 / 1008 of 9 groups clear · no organic claimProduct details →3
63 / 1008 of 9 groups clear · no organic claimProduct details →3
63 / 1008 of 9 groups clear · no organic claimFind where to buy ↗Product details →3
63 / 1008 of 9 groups clear · no organic claimProduct details →3
55 / 1007 of 9 groups clear · no organic claimFind where to buy ↗Product details →3
55 / 1007 of 9 groups clear · no organic claimFind where to buy ↗Product details →3
55 / 1007 of 9 groups clear · no organic claimFind where to buy ↗Product details →2
55 / 1007 of 9 groups clear · no organic claimProduct details →3
55 / 1007 of 9 groups clear · no organic claimProduct details →2
55 / 1007 of 9 groups clear · no organic claimProduct details →3
55 / 1007 of 9 groups clear · no organic claimFind where to buy ↗Product details →2
55 / 1007 of 9 groups clear · no organic claimProduct details →3
55 / 1007 of 9 groups clear · no organic claimProduct details →2
55 / 1007 of 9 groups clear · no organic claimFind where to buy ↗Product details →2
55 / 1007 of 9 groups clear · no organic claimFind where to buy ↗Product details →2
53 / 1008 of 9 groups clear · no organic claimProduct details →3
53 / 1008 of 9 groups clear · no organic claimFind where to buy ↗Product details →3
47 / 1006 of 9 groups clear · no organic claimProduct details →2
47 / 1007 of 9 groups clear · no organic claimFind where to buy ↗Product details →3
47 / 1006 of 9 groups clear · no organic claimProduct details →2
47 / 1006 of 9 groups clear · no organic claimProduct details →2
How the clean score works

No setup needed, and strict: a full 100 needs every additive group clear and a verified organic claim (animal foods also need a verified grass-fed or pasture-raised claim; wild seafood and salt, which have no USDA organic standard, are scored without the organic points, and plant-based milks, cheeses and proteins without the feeding claim). Points: the nine additive groups (seed oils, artificial dyes, MSG, artificial sweeteners, carrageenan, artificial preservatives, hydrogenated oils, corn syrups, banned-abroad additives) share 60 points equally — not found earns a group’s full share, “may contain” earns half, listed earns 0; a verified organic claim is worth 25; a verified grass-fed or pasture-raised claim is worth 15 and counts only for animal foods. No claim, or an expired or unverified claim, earns nothing, so products without those claims cannot reach 100. Unverified or expired ingredient labels receive no score. Equal scores are equal. Ties are ordered by brand. Unknown and stale evidence never passes “Only show matches.” Producer claims and prices do not affect this score. This is not a nutrition, allergy, or safety rating.

As an Amazon Associate I earn from qualifying purchases. Buying links do not influence ingredient results. “Buy on Amazon” opens a reviewed product listing; “Find where to buy” opens the maker’s page. Confirm the package, seller, stock, and current price before checkout. Price observations expire after 30 days.

Primary sources

Sources

  1. WHO: aspartame hazard and risk assessment results released (July 14, 2023) who.int
  2. FDA: aspartame and other sweeteners in food (current as of Feb 27, 2025) fda.gov