My diet:

E421 Mannitol

E421SweetenersOrigin: Plant
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Every diet

VeganYes
Gluten-freeYes
HalalYes
KosherYes
KetoDepends

Mannitol is only partly absorbed. Many people count about half the grams.

Low-FODMAPNo

Mannitol is a polyol, so it is out during a FODMAP elimination.

The short answer
Mannitol (E421) is a sugar alcohol, about 60% as sweet as sugar, found in mushrooms and made from fructose. It barely moves blood sugar, but it is high-FODMAP and too much causes diarrhea.
Use in moderation

Safe in small amounts; may bother some people or raise blood sugar.

E-numberE421
Comes fromPlant
What it doesSweeteners
Glycemic index0
Daily limitNot set
Also calledMannitol, D-mannitol

Rules by country

🇺🇸 US FDAApproved
🇪🇺 European UnionWarning label required
🇨🇦 Health CanadaApproved with limits
CaliforniaNo extra rules

Mannitol is GRAS in the US. In the EU, foods with more than 10% added polyols must warn that too much can have a laxative effect. Mannitol itself has no numbered daily cap.

Daily limit: Experts haven’t set a number because normal food amounts are far below any level of concern.

What is it?

Mannitol passes through the small intestine slowly. What is not absorbed draws water into the bowel. That is useful in sugar-free candy and also the reason labels warn about a laxative effect.

Where it comes from: Food mannitol is made by adding hydrogen to fructose from corn or other starch. Seaweed and mushrooms contain smaller natural amounts.

Why it’s in food

  • Sweetens sugar-free candy
  • Dusts chewing gum
  • Keeps bars soft
  • Adds a cooling taste

Often found in

Sugar-free mintsChewing gumDiabetic chocolateDried fruit coatingsMedicinal tablets

Also listed as: Mannitol, D-mannitol, Mannite

Health & gut impact

Laxative effectConcern

Mannitol in larger amounts causes bloating and diarrhea, which is why EU polyol foods carry a laxative warning.

EU Regulation 1333/2008, Annex III

Blood sugarBenefit

Mannitol is poorly metabolized, so it has almost no glycemic index.

FDA GRAS listing for mannitol, 21 CFR 180.25

Sweeteners that are easier on digestion

For your pantry
Pantry staple

Erythritol

A sugar alcohol most people tolerate in larger amounts than mannitol.

Shop erythritol Opens your country’s Amazon store
Pantry staple

Allulose

Browns in the oven and is low FODMAP for many servings.

Shop allulose Opens your country’s Amazon store
Pantry staple

Monk fruit blend

A non-polyol sweetener for drinks.

Shop monk fruit Opens your country’s Amazon store

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What can I use instead?

Erythritol

Ratio: About 1:1

Best for: Usually gentler on the gut

Allulose

Ratio: About 1:1

Best for: Baking

Related

More sweeteners:

Acesulfame Potassium (Ace-K) E950Acesulfame potassium (Ace-K, E950) is a zero-calorie sweetener approved in the US, EU and Canada. EFSA re-checked it in 2025 and raised its daily limit. It's usually paired with sucralose or aspartame to hide a slightly bitter aftertaste.Use in moderationAdvantame E969Advantame (E969) is an extremely intense sweetener related to aspartame. Regulators approve it, and the amount in a food is tiny next to the daily limit. It does not carry aspartame's phenylalanine warning at normal use.Generally safeAlluloseAllulose is a "rare sugar" that tastes like sugar but has almost no calories and doesn't raise blood sugar. It's keto-friendly and browns like real sugar in baking.Generally safeAspartame E951Aspartame (E951) is a zero-calorie sweetener in diet soda. It's approved, but WHO's cancer agency called it "possibly carcinogenic" in 2023, and people with PKU must avoid it.Use in moderation

Common questions

Why do mushrooms bother some people on a low-FODMAP diet?

Common mushrooms are rich in mannitol, the same polyol as E421. Both are avoided in the elimination phase.

Is Mannitol safe?

Use in moderation (70/100). Mannitol is GRAS in the US. In the EU, foods with more than 10% added polyols must warn that too much can have a laxative effect. Mannitol itself has no numbered daily cap.

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Scientific sources & regulatory citations
  • 21 CFR 180.25 (US FDA)
  • EFSA OpenFoodTox: E421
  • EU Regulation 1333/2008, Annex III
  • FDA GRAS listing for mannitol, 21 CFR 180.25

INS 421 · CAS 69-65-8