Sweeteners/Artificial high-intensity

Aspartame

Also known as: Equal, NutraSweet

PoorArtificial high-intensityE951

Methyl ester of aspartic acid + phenylalanine. WHO/IARC classified 2B (possibly carcinogenic) in 2023.

38
SweetSpot score
Sweetness vs sugar
200×
Glycemic index
0
no glucose response
Calories
4 kcal/g
Verdict
Poor

At a glance

6 of 10 metrics graded

How Aspartame compares to table sugar on the three numbers most people actually want.

Sweetness vs sugar
200×
vs sugar 1×
Used in trace amounts
Glycemic index
0
vs sugar 65
No glucose response
Calories per gram
4 kcal
vs sugar 4 kcal
Same as sugar
SweetSpot score
38/100
AvoidPoorModerateGoodExcellent

Ten-metric breakdown

See methodology →
  • Taste quality
    Weight 20%
    80
  • Glycemic impact
    Weight 18%
    40
  • Naturalness
    Weight 10%
    10
  • Tooth friendliness
    Weight 8%
    90
  • Overall safety
    Weight 14%
    Pending
  • Digestive comfort
    Weight 8%
    70
  • Gut microbiome
    Weight 8%
    Pending
  • Aftertaste
    Weight 6%
    Pending
  • Sustainability
    Weight 4%
    Pending
  • Allergen safety
    Weight 4%
    60

Source: public.sweeteners snapshot, refreshed 2026-04-27. "Pending" cells are catalogued but not yet graded by SweetSpot research.

What it actually is

Aspartame is a dipeptide of aspartic acid and phenylalanine, methylated. In the gut it is hydrolysed to its three constituents — methanol, aspartic acid, phenylalanine — and absorbed normally. It is technically caloric (4 kcal/g) but used at such low doses that the contribution is negligible.

In July 2023 IARC classified aspartame as Group 2B — 'possibly carcinogenic to humans' — citing limited evidence in humans for hepatocellular carcinoma. JECFA simultaneously reaffirmed the existing ADI. Real-world reading: a 70 kg adult would need to drink around 14 cans of diet soda (≈180 mg aspartame each) every day to reach the JECFA / EFSA ADI of 40 mg/kg — the FDA limit allows roughly 19. The 2B designation is a hazard signal, not a risk verdict at typical intake.

There is one absolute contraindication: PKU (phenylketonuria). People with PKU cannot metabolise phenylalanine and must avoid aspartame entirely — which is why every aspartame-containing product carries a phenylalanine warning.

What it does well
  • Long history (since 1981) of regulatory study
  • Effectively zero calories at use levels
  • Cheap — used in most diet sodas
Where it falls short
  • WHO/IARC Group 2B 'possibly carcinogenic' (2023)
  • Absolute contraindication in phenylketonuria
  • Bitter aftertaste at higher concentrations

Regulatory status

FDA (United States)
Approved (1981)
EFSA (Europe)
Authorised E951
Acceptable daily intake
JECFA / EFSA: 40 mg/kg bw/day · FDA: 50 mg/kg bw/day

In practice

Best for
  • Diet soda — if you tolerate the taste and have no PKU
Avoid if
  • Phenylketonuria (absolute)
  • Pregnancy (some maternal-health groups recommend reducing — formal ADI unchanged)
  • Heavy daily diet-soda use
Where you'll find it

Diet Coke, Diet Pepsi, Equal, sugar-free yogurts

The evidence

Selected peer-reviewed sources behind the score. Open access where possible. Read our scoring methodology for how we weight evidence tiers.

Recommended swaps

Higher-scoring alternatives that perform similarly in use.

Monk Fruit
86

Mogrosides from Siraitia grosvenorii. 150–250× sweeter, no glycemic effect, cleaner aftertaste than stevia.

Stevia
78

Steviol glycosides from Stevia rebaudiana. 200–400× sweeter than sugar, zero glycemic.

Allulose
88

A rare sugar that tastes 70% as sweet as sucrose with ~10% the calories and a negligible — sometimes mildly suppressive — insulin response.