What is E626?

Complete guide to understanding guanylic acid in your food

The Quick Answer

E626 is guanylic acid, a flavor-enhancing food additive derived from nucleotides.

It’s used in food to boost savory flavors and reduce the amount of salt needed.

Most people who eat processed snacks and instant noodles consume it regularly.

What Exactly Is E626?

E626 is guanylic acid (5′-guanylic acid), also known as guanosine monophosphate (GMP).

It’s a white crystalline powder that occurs naturally in the genetic material (DNA and RNA) of every living cell. In fact, guanylic acid is one of the building blocks of RNA—the molecule that carries genetic instructions in all organisms.

The name “guanylic acid” comes from “guanine,” one of the nucleobases found in DNA and RNA.

In technical terms, it’s a nucleotide monophosphate, but you don’t need to understand the chemistry. What matters is that your body already contains this substance naturally.

E626 vs. Related Guanylates (E627-E629)

E626 is the pure form, but it’s rarely used directly in food.

Instead, manufacturers use salt forms of guanylic acid:

– E626 = Guanylic acid (pure form)
– E627 = Disodium guanylate (most common in foods)
– E628 = Dipotassium guanylate
– E629 = Calcium guanylate

All work identically as flavor enhancers. The main difference is which mineral (sodium, potassium, or calcium) is paired with the guanylic acid.

Where You’ll Find E626 and Its Salts

E626/E627 appears in savory processed foods, especially:

– Instant noodles and ramen
– Potato chips and snacks
– Canned and packet soups
– Convenience prepared meals
– Savoury rice dishes
– Cured meats
– Canned vegetables
– Sauces and seasonings

Approximately 50% of processed convenience foods in supermarkets contain E626 or its related salts.

Why Do Food Companies Use E626?

E626 has one main job: enhance savory flavors.

Unlike MSG (E621), which creates umami taste directly, E626 does NOT provide its own taste. Instead, it amplifies existing flavors in food—making convenience meals taste more flavorful despite ingredient loss during industrial processing like drying.

E626 and its salts are up to 20 times more potent than glutamates (like MSG), which means food manufacturers need to add very little.

Most importantly, E626 allows companies to reduce salt content. When combined with small amounts of salt, it delivers full flavor impact with less sodium—valuable for reducing dietary salt intake.

So food companies use it because it’s effective, inexpensive, and allows healthier formulations.

Is It Safe?

Regulatory authorities say E626 is safe.

The FDA includes it in the GRAS (Generally Recognized As Safe) list. The EFSA and WHO’s JECFA committee both approved it. A 1993 JECFA review found no evidence of carcinogenicity, genotoxicity, or adverse reproductive effects.

An Acceptable Daily Intake (ADI) was not specifically quantified—it was designated as “not specific”—which indicates no clear safety threshold needed to be set because the compound posed no identifiable risk at tested doses.

No reported side effects exist in healthy individuals at normal consumption levels.

The Gout Connection – Why This Matters

This is the key health distinction for E626.

When your body breaks down guanylic acid, it converts it to uric acid as a metabolic byproduct. Humans lack an enzyme (uricase) that other mammals possess to further break down uric acid, so it accumulates in the bloodstream.

For people with normal uric acid metabolism, consuming E626 in typical food amounts poses no issue. But for those with gout (a painful condition caused by uric acid crystal accumulation in joints) or those prone to uric acid kidney stones, additional dietary sources of purines—including E626—can trigger or worsen symptoms.

This is not an acute toxicity concern like spoiled food might cause. Rather, it’s a metabolic concern for a specific population.

Natural Sources of Guanylic Acid

E626 isn’t a man-made chemical invented in a lab.

Guanylic acid occurs naturally in all living cells as part of their genetic material. It’s especially abundant in dried mushrooms—the drying process breaks down RNA, releasing significant amounts of GMP.

So if you’ve eaten mushrooms, aged cheese, or meat, you’ve consumed natural guanylic acid. The additive form is chemically identical to the natural version.

How E626 Is Made

Modern E626 production uses microbial fermentation.

The process typically involves:

1. Fermenting sugars using bacteria to produce guanosine
2. Chemically converting guanosine to GMP (guanylic acid)
3. Neutralizing with sodium hydroxide (or potassium/calcium compounds) to create the salt form used in foods

This is the same type of fermentation used to make yogurt, beer, and antibiotics—nothing exotic or artificial.

How E626 Differs from MSG (E621)

This is crucial to understand.

Many people confuse E626 with MSG, but they work differently:

– E621 (MSG) creates umami taste directly. It tastes savory/meaty on its own.
– E626 (Guanylic acid) does NOT taste like umami. It enhances other flavors and works best when combined with MSG.

In fact, E626 and E627 are often added together with MSG to create a synergistic effect—the combination is more potent than either ingredient alone.

Natural vs. Synthetic E626

Modern commercial production of E626 uses industrial fermentation from sugar sources, making it neither purely “natural” nor purely “synthetic”—it’s manufactured using biological processes.

However, the final molecule is identical to guanylic acid that occurs naturally in mushrooms, meat, and other foods. Your body cannot distinguish between the two sources.

Vegan, Halal, Kosher, and Gluten-Free Status

E626/E627 is generally suitable for:

– Vegan diets (when produced via fermentation methods)
– Halal diets (generally recognized as halal)
– Kosher diets (kosher pareve classification)
– Gluten-free diets

However, verify with manufacturers, as some sources may use animal-derived materials.

Alternatives to E626

Want to avoid E626 and related guanylates?

Food companies sometimes use:

– Disodium inosinate (E631)—another nucleotide flavor enhancer
– Disodium 5′-ribonucleotides (E635)—a mixture of guanylates and inosinates
– Regular salt and MSG (E621)
– Natural herbs and spices

These alternatives typically cost more, explaining why E626 remains the industry standard.

The Bottom Line

E626 (guanylic acid) is a naturally occurring nucleotide used as a flavor enhancer in processed foods.

Regulatory authorities worldwide classify it as safe for the general population at typical consumption levels.

It does not create umami taste itself but enhances existing savory flavors, and it’s significantly more potent than glutamate-based enhancers.

Unlike MSG (E621), E626 has no documented acute toxicity or allergic reactions in humans.

However, people with gout or a history of uric acid kidney stones should avoid or strictly limit E626 consumption, as it metabolizes to uric acid in the body.

As always, food labels must declare E626 and related additives by name or E-number, so you can make informed dietary choices.