E626 - Guanylic acid

At a glance

• What it is: A 5'-ribonucleotide (GMP) that enhances umami taste.
• What it does: Intensifies savory flavors and works especially well with glutamate.
• Where it’s used: Savory snacks, instant noodles, bouillon and stocks, sauces, and ready meals.
• Also seen as: “Guanylic acid,” “guanosine monophosphate,” or “E626” on labels.
• Related additives: Its salts include E627, E628, and E629; it is often blended with E631 or E635.

Why is Guanylic acid added to food?

Food makers add E626 to lift umami, the savory taste that makes broths, meats, mushrooms, and aged cheeses so satisfying. Guanylic acid is very potent, so only small amounts are needed. It is often combined with glutamate (for example, monosodium glutamate) because the two work together to create a stronger, fuller savory flavor than either alone.

What foods contain Guanylic acid?

You’ll most often find E626 in:

• Bouillon cubes, soup bases, and gravies
• Instant noodles and seasoning sachets
• Savory snacks like chips and crackers
• Sauces, dressings, and marinades
• Ready-to-eat and ready-to-heat meals

In the European Union, guanylic acid (and its related salts) is authorized as a food additive in various food categories under the Union list of permitted additives.¹

What can replace Guanylic acid?

• Monosodium glutamate (MSG) can deliver umami on its own in many recipes.
• Inosinates such as disodium inosinate or inosinic acid provide a similar savory lift.
• Blends of 5'-ribonucleotides like disodium 5'-ribonucleotide are designed to mimic the synergy of guanylates and inosinates.
• The salts of guanylic acid—disodium guanylate, dipotassium guanylate, and calcium guanylate—are functionally similar and are used when a salt form fits the product better.

How is Guanylic acid made?

Commercially, E626 is typically produced by fermenting a food-grade microorganism, generating RNA (ribonucleic acid) that is then enzymatically processed to yield guanosine 5'-monophosphate (GMP). The product is purified, dried, and standardized to meet identity and purity specifications for food use.² Chemically, guanylic acid is the free-acid form of GMP, the guanine nucleotide found naturally in living cells.³

Is Guanylic acid safe to eat?

In the European Union, guanylic acid is authorized as a food additive and may be used only in the foods and at the levels laid down in EU additive law.¹ Its composition and purity criteria are defined in EU specifications to help ensure consistent quality and safety in commerce.² In the United States, FDA’s Food Additive Status List includes guanosine 5'-monophosphate among substances added to food, reflecting its recognized use as a flavor enhancer.⁴

Does Guanylic acid have any benefits?

From a culinary standpoint, E626 helps foods taste richer and more satisfying, especially when paired with glutamate. Because it is highly potent, manufacturers can use very small amounts to achieve a noticeable flavor improvement.

Who should avoid Guanylic acid?

If your healthcare provider has advised you to limit dietary purines (for example, to manage high uric acid or gout), you may wish to moderate foods with added 5'-ribonucleotides such as guanylic acid. When in doubt, check labels for “E626,” “guanylic acid,” or “guanosine monophosphate.”

Myths & facts

• Myth: “E626 is the same as MSG.” Fact: They are different compounds; guanylic acid is a nucleotide, while MSG is a glutamate salt. They are often used together because they complement each other.
• Myth: “It adds a strong artificial taste.” Fact: At typical levels, E626 boosts the food’s own savory notes rather than adding a distinct new flavor.
• Myth: “It always raises sodium.” Fact: Guanylic acid is the acid form; some salt forms (like disodium guanylate) add sodium, but E626 itself does not add much sodium.

Guanylic acid in branded foods

On ingredient lists, look for “E626,” “guanylic acid,” or “guanosine monophosphate.” It often appears alongside monosodium glutamate or other nucleotides such as disodium inosinate or disodium 5'-ribonucleotide. Common places to see it include stock cubes, instant noodle seasonings, savory snack coatings, and jarred or canned sauces.

References

Footnotes

1. Regulation (EC) No 1333/2008 on food additives — Union list and conditions of use. https://eur-lex.europa.eu/eli/reg/2008/1333/oj ↩ ↩²

2. Commission Regulation (EU) No 231/2012 — Specifications for food additives listed in Annexes II and III to Regulation (EC) No 1333/2008. https://eur-lex.europa.eu/eli/reg/2012/231/oj ↩ ↩²

3. Guanosine 5'-monophosphate — PubChem, National Institutes of Health. https://pubchem.ncbi.nlm.nih.gov/compound/Guanosine-5%27-monophosphate ↩

4. Food Additive Status List — U.S. Food and Drug Administration (FDA). https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩