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E303 · Antioxidants

Potassium ascorbate

No known risk

A safe and highly beneficial Vitamin C salt.

Category
Antioxidants
Vegan
Yes
Vegetarian
Yes

What it is

The potassium salt of Vitamin C (ascorbic acid), used as a dietary supplement and antioxidant.

How it is used in food

Potassium ascorbate is a neutral-tasting salt of vitamin C that scavenges oxygen and free radicals without the tartness or metal-corroding acidity of ascorbic acid. It preserves colour and flavour in low-acid foods and beverages while contributing genuine vitamin C activity and a small amount of potassium.

Commonly found in
  • Dietary supplements
  • Beverages

Health and safety

Completely safe, providing both Vitamin C and potassium. Not formally listed on the main EU food additive Annex, but used in supplements.

EFSA's re-evaluation of ascorbic acid and its sodium and calcium salts (E 300–E 302) found no safety concern and set no numerical ADI. Potassium ascorbate is not on the EU's main additive Annex, but it is a permitted vitamin C source in food supplements and fortified foods under the EU nutrient-source rules.

Regulatory status

RegionStatusNotes
Australia & New Zealand
FSANZ
Permitted Permitted under the FSANZ Food Standards Code.
European Union
EFSA / European Commission
Not approved Not on the EU authorised list of food additives (Annex II).
United States
FDA (Food and Drug Administration)
Permitted Authorised for food use by the FDA (often GRAS for standard additives).

Identification on labels

E-number
E303

Worth knowing

The buffered form exists mainly for palatability: because it is close to pH-neutral, it can be taken in gram quantities or added to delicate drinks without the sour bite or dental-enamel concerns that come with plain ascorbic acid.

Conclusion

A safe and highly beneficial Vitamin C salt.

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Entry last reviewed 2026-07-28.

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