My diet:

Whey

No E-numberEmulsifiersOrigin: Animal
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Every diet

VeganNo

Whey is the liquid from cheesemaking.

Gluten-freeYes
HalalYes

Milk is the source. Rennet, if used upstream, is a separate certification question.

KosherYes

Whey is dairy.

KetoDepends

Sweet whey and dried whey are mostly lactose, a sugar. A whey protein isolate has most of that sugar removed.

Low-FODMAPDepends

Lactose is a FODMAP. Isolates with the lactose removed are a different case.

The short answer
Whey is the liquid left from making cheese. Dried whey is mostly milk sugar, so it is not vegan and often not keto. A whey protein isolate is the same stream with most of that sugar taken out.
Use in moderation

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

E-numberNone
Comes fromAnimal
What it doesEmulsifiers
Glycemic index—
Daily limitNot set
Also calledWhey, Sweet whey

Rules by country

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

The FDA affirms whey, concentrated whey and dried whey as GRAS (21 CFR 184.1979). A finished food lists them as whey. Europe and Canada treat whey as a dairy food, not as an E-number. Sweet whey powder is mostly lactose. A protein isolate is a different product with most of that sugar removed.

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

What is it?

Liquid whey is pale and tart or sweet depending on the cheese. Dried, it browns baked goods and adds dairy solids. Concentrated protein is what shaker bottles use.

Where it comes from: The FDA defines whey as the liquid left when the curd is separated from milk, cream or skim milk in cheesemaking. Sweet whey comes from rennet curds and is mostly lactose plus protein. Acid whey comes from acid-set cheeses and is tarter. Whey protein concentrate is that liquid with enough of the non-protein part removed that the dry powder is at least 25 percent protein (21 CFR 184.1979c).

Why it’s in food

  • Adds dairy solids to bread and crackers
  • Browns a crust
  • Feeds a protein shake when it is the concentrate or isolate
  • Carries flavor in a seasoning

Often found in

Bread and crackersProtein shakesBaked goodsSeasoning blendsInfant formulaProcessed cheese

Also listed as: Whey, Sweet whey, Dried whey, Whey powder, Whey protein concentrate

Health & gut impact

Lactose in the powderConcern

The FDA's identity of dried whey still contains a large share of lactose. People who do not make lactase feel that sugar.

21 CFR 184.1979

Concentrate is not the same powderBenefit

Whey protein concentrate has to be at least 25 percent protein on a dry basis. More of the lactose has been removed than in plain dried whey.

21 CFR 184.1979c

What can I use instead?

Pea protein

Ratio: Use it in a shake, not as a browning sugar

Best for: A vegan protein

Soy protein isolate

Ratio: Expect a different flavor

Best for: A vegan dairy-style protein

Related

More emulsifiers:

Acetylated monoglycerides E472aAcetylated monoglycerides (E472a) are fat-based emulsifiers that help bread hold air and keep whipped toppings stable. They are common in bakery and generally considered safe; check the source fat if you avoid animal ingredients.Use in moderationAmmonium phosphatides E442Ammonium phosphatides (E442) are a chocolate emulsifier made from vegetable oil. They are an alternative to soy lecithin when a recipe needs chocolate to flow, and they are considered safe.Generally safeBrominated vegetable oil (BVO)Brominated vegetable oil (BVO) kept the citrus flavor from floating to the top of some sodas. The FDA banned it in 2024 because of thyroid effects, so check older or imported citrus drinks.Best to avoidCalcium stearoyl lactylate E482Calcium stearoyl lactylate (E482) is a dough strengthener that helps bread rise and stay soft. Its fat source varies, so vegans and people following halal or kosher rules should check the label.Use in moderation

Common questions

Is whey vegan?

No. It comes from milk.

Is whey keto?

Dried sweet whey is mostly lactose, so no. A protein isolate with the lactose removed can fit a keto count. Read which one the label names.

Is Whey safe?

Use in moderation (76/100). The FDA affirms whey, concentrated whey and dried whey as GRAS (21 CFR 184.1979). A finished food lists them as whey. Europe and Canada treat whey as a dairy food, not as an E-number. Sweet whey powder is mostly lactose. A protein isolate is a different product with most of that sugar removed.

Is Whey vegan?

No. Whey is the liquid from cheesemaking.

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Scientific sources & regulatory citations
  • 21 CFR 184.1979 (US FDA)
  • 21 CFR 184.1979
  • 21 CFR 184.1979c