Back to catalogSafety
E421SweetenerLow concern
Mannitol
In plain words
The short version
A sugar alcohol from seaweed and tree saps — used as a non-cariogenic sweetener and tablet excipient.
Why it's green
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Safety profile
ADI not specified — considered safe. Like other polyols, large oral doses (~20 g) can cause a laxative effect. Slow GI absorption and partial colonic fermentation. Non-cariogenic — does not feed dental-plaque bacteria.
The detail
Naturally present in seaweed, manna ash sap (the historical source — the name comes from biblical 'manna'), and many fungi. Industrially produced by hydrogenation of fructose or sucrose hydrolysates. The C-2 epimer of sorbitol.
About 60% as sweet as sucrose with strong cooling sensation on the tongue. Used in sugar-free gums and confectionery, diabetic foods, and as a tablet excipient (non-hygroscopic and compresses well). Outside food, clinical use as an intravenous osmotic diuretic for cerebral edema.
White crystalline powder. Sparingly soluble in water at room temperature (less hygroscopic than sorbitol — a key tabletting advantage). Heat-stable.
Permitted globally with mandatory laxative-effect labeling at higher intake.
Sources
- WHO JECFA database: Mannitol (INS 421), ADI not specified (30th meeting, 1986) — WHO / FAO Joint Expert Committee on Food Additives, 1986. ADI not specified
- US eCFR: 21 CFR 180.25 Mannitol (interim food additive, use limits and laxative statement) — US Office of the Federal Register / FDA, 2026. Laxative-effect labelling at about 20 g/day; US regulatory status
- EU: Regulation (EU) No 1169/2011 on food information to consumers, Annex III point 2.4 (polyols laxative warning) — European Union (Publications Office), 2011. Mandatory laxative-effect labelling in the EU
- EU: Commission Regulation (EU) No 1129/2011 establishing the Union list of food additives (Annex II to Reg. 1333/2008), as adopted — European Union (Publications Office), 2011. E 421 authorised in the EU (polyols group)
Checked against these sources on .
Educational information only. Not medical, dietary or veterinary advice. Spotted an error? Tell us.