Is Disodium Inosinate (E631) Vegan?

Also known as: IMP, Inosinic acid disodium salt

Depends on Source

Last checked 10 Sept 2026 How we decide Edited by Anna Polovnikova

Disodium inosinate depends on how it was made. The leading producers report making E631 by microbial fermentation on plant-based media, and it can also be made from fish, sardines and anchovies among them, or from meat. Seeing it beside MSG on an instant noodle packet is the usual pattern, and the packet will not say where it came from.

Which animal, and does it die

Comes from: fish or meat animals, via extracts
Requires slaughter: Yes

Vegetarian depends on the source

From a mammalRelevant to alpha-gal syndrome
Fish-derivedRelevant to a fish allergy

These flags describe sourcing. They are not an allergen assessment, and a vegan label is not a free-from claim. If you have an allergy, read the allergen declaration on the pack.

Ingredient Data

Vegan Status

Depends on Source

E-Number

E631

Also Known As

IMP; Inosinic acid disodium salt

Source

Made by microbial fermentation on plant-based media, the route the leading producers report, or derived from fish (sardines, anchovies) or meat. Every route gives the same name on the label.

Commonly Found In

Instant noodles, crisps/chips, flavored snack foods, bouillon cubes, fast food seasonings. Almost always used together with E627 and MSG.

Vegan Alternative

There is no direct flavor substitute. Avoid products listing E631 unless the manufacturer confirms a non-animal source.

Additional Notes

E631 is a flavor enhancer that synergizes with MSG. If a product contains MSG (E621) along with E631 or E635, the flavor is boosted with nucleotides made by fermentation or from fish or meat. Particularly common in Asian snack foods and instant noodles.

In depth

How Disodium Inosinate Is Produced

Disodium inosinate is the sodium salt of inosinic acid, a nucleotide that occurs naturally in animal muscle tissue and at much lower levels in other living tissues. The compound was first identified in dried bonito flakes, a traditional Japanese ingredient, and it can be made from fish and meat sources such as sardines, anchovies, and meat extracts.

Production can also proceed through microbial fermentation. Bacteria are cultured on sugars or starch to yield the nucleotide, with no direct use of animal tissue. The leading producers report using this route on plant-based media, and manufacturers rarely specify which method was used for a given batch.

Because the two sourcing routes produce a chemically identical additive, the finished ingredient carries no marker of its origin. Vegan reference work therefore treats it cautiously: the label reveals the substance but not its history.

Reading Labels and the E627 Connection

Disodium inosinate appears on ingredient lists as "disodium inosinate," "disodium 5'-inosinate," "IMP," or the European code E631. It almost never appears alone. Manufacturers routinely pair it with disodium guanylate (E627). The two nucleotides act together to amplify savory taste far more effectively than either does by itself.

When the two are blended in roughly equal proportion, they may be listed under a single combined name, disodium 5'-ribonucleotides, coded E635. Seeing E635 on a label therefore implies the presence of inosinate. These additives also work in synergy with monosodium glutamate (E621), so the trio E621 with E627 or E635 is a common signature on savory processed foods.

No standard label statement discloses whether the inosinate was fish-derived or fermentation-derived. The code alone does not settle the question of origin.

Alternatives and How They Compare

No single drop-in replacement reproduces the specific taste-amplifying effect of disodium inosinate. Several plant-based ingredients do deliver comparable savory depth. Dried shiitake mushrooms are one example, since they naturally contain guanylate-type nucleotides that boost umami. Yeast extract, nutritional yeast, tomato paste, seaweeds such as kombu, fermented soy products like miso and soy sauce, and slow-cooked vegetable or mushroom stocks all contribute glutamates and related compounds that build savory character.

These alternatives function differently from a purified additive. A purified additive sharply intensifies an existing flavor at very low doses. The plant-based sources add their own background taste, so recipes usually need adjusting, without a one-for-one swap.

For consumers avoiding animal-derived additives, choosing whole-food umami sources or products that explicitly state a plant or fermentation origin is the most reliable approach.

Products Where It Commonly Appears

Disodium inosinate is widespread in savory processed food. Instant noodle seasoning sachets, bouillon and stock cubes, potato and corn chips, flavored crackers, dry seasoning blends, and the coating or dip powders used in fast food and snack products all carry it frequently. Many Asian snack foods and instant meals use it especially often, where intense savory flavor is a defining characteristic.

People are sometimes surprised to find it in products marketed as simple or vegetable-based, such as certain vegetable-flavored chips or plant-forward instant soups. The additive itself carries no obvious animal name on the label.

The code E631 gives no indication of source. Shoppers who wish to avoid animal-derived nucleotides generally scan for E631, E627, and E635 together. Where origin matters to them, they look for a manufacturer statement.

What E631 Is and What It Does

E631 is the code under which the EU authorizes disodium inosinate as a food additive, and international specifications list the same substance as INS 631. Its chemical name is disodium inosine-5'-monophosphate. The additive itself comes as colorless or white crystals or as a white crystalline powder, odorless and soluble in water.

Its job is taste. Alone its umami taste is weak. Mixed with glutamate it multiplies savory flavor, and a review of umami research reports that in people the taste response to a mixture of glutamate and inosinate is about eight times the response to glutamate alone. That is why a small dose sits beside MSG (E621) in so many seasonings.

In the United States, labels give the name disodium inosinate in place of a code, and federal rules permit it as a flavoring adjuvant.

How to Find Out Which Route a Product Used

A vegan certification mark or a clear answer from the manufacturer settles it, because the ingredient list stays silent on origin. EU rules have a flavor enhancer declared by its category name followed by its specific name or E number, so "flavor enhancer (E631)" is a complete declaration whether the inosinate came from fish, meat, or microbial fermentation. Official records are thin too: in March 2024 the European Food Safety Authority reported a manufacturing data gap for the whole E626 to E635 group then under re-evaluation.

Certification is the quickest check, because vegan standards reach into how each ingredient was made. The Vegan Society Trademark and V-Label Vegan both cover every stage of production, processing aids included, and Certified Vegan requires verification that every ingredient and sub-ingredient was made free of animal products and by-products. A certified product that lists E631 therefore uses an animal-free version.

For an uncertified product, ask the manufacturer one precise question: does the disodium inosinate in this product, or the E635 that contains it, come from microbial fermentation or from fish or meat? Ask for the reply to be checked with their ingredient supplier, and keep its date, because producers change formulas quietly.

Two familiar marks answer a different question. A kosher pareve mark allows fish, and a halal mark allows fish and meat from permitted animals, so both leave an animal route open.

Frequently asked questions

Is disodium inosinate vegan?

Disodium inosinate depends on how it was made. The additive can be derived from fish or meat, and labels do not disclose the source. The leading producers report making it by microbial fermentation on plant-based media, a route that uses no animal tissue. Unless a manufacturer confirms a non-animal origin, the additive is best regarded as potentially animal-derived.

What is E631 made from?

E631 is the sodium salt of inosinic acid. That nucleotide occurs naturally in animal muscle. Commercially it can be sourced from fish such as sardines and anchovies or from meat extracts. Bacterial fermentation of sugars or starch can also produce it, and the leading producers report using that route. The finished additive is chemically the same regardless of route, so the label does not indicate which was used.

Is disodium inosinate the same as MSG?

No, disodium inosinate is not the same as MSG. MSG (monosodium glutamate, E621) is the salt of glutamic acid. Disodium inosinate (E631) is a nucleotide salt. They are different compounds. Cooks and manufacturers use them together because inosinate strongly amplifies the savory effect of glutamate.

What can I use instead of disodium inosinate?

There is no exact substitute. Plant-based umami sources can provide similar savory depth. Dried shiitake mushrooms, yeast extract, nutritional yeast, kombu seaweed, miso, soy sauce, and tomato paste all add savory character. Each brings its own flavor, and none of them simply intensifies at trace levels. Recipes usually need adjusting, without a one-for-one swap.

Is disodium inosinate found in chips and instant noodles?

Yes, disodium inosinate is very common in chips, flavored snacks, and instant noodle seasoning. Makers use it to intensify savory flavor, almost always paired with disodium guanylate (E627) and often MSG (E621). If you see the codes E631, E627, or E635 on a snack or noodle label, the flavor is being boosted with these nucleotides.

Is E631 vegetarian?

E631 is vegetarian when it comes from microbial fermentation, the route three leading manufacturers described to the Vegetarian Resource Group in 2011. A version extracted from fish or meat would come from slaughtered animals. Every route gives the same name on the label, so a vegan mark or a statement from the manufacturer confirms which one a product used.