Soy protein isolate (Isolated soy protein)

No E-numberEmulsifiersOrigin: Plant

Get a personal answer

Pick your family’s diets in the bar above.

Every diet

VeganYes

The isolate is soybean protein.

Gluten-freeYes

HalalYes

KosherYes

Soy is kitniyot for Passover.

KetoYes

It is protein, with little carbohydrate left.

Low-FODMAPYes

Most of the GOS went out with the carbohydrate fraction.

The short answer

Soy protein isolate is soybean protein with most of the fat and carbohydrate removed. It is vegan and gluten-free. A soy allergy still applies, and it is a highly refined powder, not a whole bean.

72/100

Use in moderation

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

E-numberNone

Comes fromPlant

What it doesEmulsifiers

Glycemic index—

Daily limitNot set

Also calledSoy protein isolate, Isolated soy protein

Rules by country

🇺🇸 US FDANot evaluated as an additive

🇪🇺 European UnionNot evaluated as an additive

🇨🇦 Health CanadaNot evaluated as an additive

CaliforniaNo extra rules

Soy protein isolate is a food protein, not an E-number. A soy allergy applies to it. A heart-disease claim for 25 grams of soy protein a day is still written at 21 CFR 101.82, and the FDA has proposed revoking that claim. The isolate itself is not banned.

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

What is it?

The powder emulsifies, binds water and adds protein to a bar or a meat alternative. It tastes milder than soy flour.

Where it comes from: Soy protein isolate is the protein of the soybean, separated from most of the fat and carbohydrate. Flakes are defatted, the protein is dissolved, and then it is precipitated and dried. What remains is a powder around 90 percent protein.

Why it’s in food

Builds a vegan burger or a sausage
Raises the protein in a bar
Emulsifies a drink
Binds water in processed meat

Often found in

Veggie burgersProtein barsMeat alternativesProcessed meatsInfant formula in some brandsProtein shakes

Also listed as: Soy protein isolate, Isolated soy protein, Soy protein isolated, ISP

Health & gut impact

Soy allergyConcern

Isolate is concentrated soy protein. Anyone with a soy allergy has to avoid it, whatever the health-claim language on the front.

Major-allergen labeling for soy

Not the whole beanUnder study

Making the isolate removes fiber and most of the carbohydrate, and it concentrates the protein. That is a different food from edamame or tofu.

Process description of isolated soy protein

What can I use instead?

Pea protein

Ratio: Match the protein grams, not the scoops

Best for: A soy-free vegan protein

Vital wheat gluten

Ratio: Only where gluten is wanted

Best for: A chewy vegan loaf

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 moderation Ammonium 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 safe Brominated 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 avoid Calcium 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 soy protein isolate vegan?

Yes.

Is it safe?

Regulators allow it as food. The clear reason to skip it is a soy allergy, not a ban.

Is Soy protein isolate safe?

Use in moderation (72/100). Soy protein isolate is a food protein, not an E-number. A soy allergy applies to it. A heart-disease claim for 25 grams of soy protein a day is still written at 21 CFR 101.82, and the FDA has proposed revoking that claim. The isolate itself is not banned.

Is Soy protein isolate vegan?

Yes. The isolate is soybean protein.

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Scientific sources & regulatory citations

Major-allergen labeling for soy
Process description of isolated soy protein