My diet:

Lactose (Milk sugar)

No E-numberSweetenersOrigin: Animal
Get a personal answer

Pick your family’s diets in the bar above.

Every diet

VeganNo

Lactose comes from milk.

Gluten-freeYes
HalalYes

Milk sugar from milk is generally halal.

KosherYes

It is dairy, so it is not pareve.

KetoNo

Lactose is a sugar.

Low-FODMAPNo

Lactose is one of the FODMAPs.

The short answer
Lactose is milk sugar. It is not vegan, it is a FODMAP, and it bothers people who do not make lactase. It is not the same thing as a milk-protein allergy.
Use in moderation

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

E-numberNone
Comes fromAnimal
What it doesSweeteners
Glycemic index46
Daily limitNot set
Also calledLactose, Milk sugar

Rules by country

🇺🇸 US FDANot evaluated as an additive
🇪🇺 European UnionNot evaluated as an additive
🇨🇦 Health CanadaNot evaluated as an additive
CaliforniaNo extra rules

Lactose is a milk food, not an E-number. People who lack the enzyme lactase get gas and cramps from it. That is intolerance, not a milk-protein allergy. A milk allergy is a reaction to proteins such as casein, and those proteins are a different ingredient.

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

What is it?

Lactose crystals are white and only slightly sweet. Formula, whey powders and many tablets use it as a filler that the body can digest when lactase is present.

Where it comes from: Lactose is the sugar in milk, a glucose joined to a galactose. Refiners crystallize it out of whey, the liquid left from cheesemaking. It tastes only mildly sweet, which is why pills and infant formula can use a lot of it without tasting like candy.

Why it’s in food

  • Fills tablets and capsules
  • Feeds the browning of baked goods
  • Sweetens infant formula mildly
  • Standardizes milk powders

Often found in

Infant formulaWhey powder and dried milkTabletsBaked goodsChocolate that uses milk solidsSome sausages

Also listed as: Lactose, Milk sugar, Lactose monohydrate, Milk lactose

Health & gut impact

IntoleranceConcern

Without enough lactase, lactose reaches the colon and ferments. The result is gas, cramps and loose stools, and the amount that does it varies by person.

NIDDK, lactose intolerance

Not a milk allergyBenefit

A milk allergy is an immune reaction to milk proteins. Lactose is the sugar. Someone can have one problem and not the other.

NIAID descriptions of milk allergy versus lactose intolerance

What can I use instead?

Table sugar

Ratio: Expect more sweetness from the same spoon

Best for: A recipe that does not need milk sugar

Dextrose

Ratio: Use it when a mild, vegan sugar is the goal

Best for: Tablets and bakery browning

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 safeAgave syrup (Agave nectar)Agave syrup is a plant sweetener that is mostly fructose. It barely moves blood sugar, and it is still sugar: skip it on keto and in a low-FODMAP elimination.Use in moderationAlluloseAllulose 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 safe

Common questions

Is lactose vegan?

No. It is crystallized from whey.

I am lactose intolerant. Is that a milk allergy?

No. Intolerance is missing lactase. A milk allergy is a reaction to proteins such as casein.

Is Lactose safe?

Use in moderation (72/100). Lactose is a milk food, not an E-number. People who lack the enzyme lactase get gas and cramps from it. That is intolerance, not a milk-protein allergy. A milk allergy is a reaction to proteins such as casein, and those proteins are a different ingredient.

Is Lactose vegan?

No. Lactose comes from milk.

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Scientific sources & regulatory citations
  • NIDDK, lactose intolerance
  • NIAID descriptions of milk allergy versus lactose intolerance

CAS 63-42-3