E628 · Dipotassium guanylate

What is E628?

Dipotassium guanylate is the potassium salt of guanylic acid, used as a flavor enhancer, often combined with MSG to boost umami taste in processed foods, seasonings, and soups. It is approved by EFSA and the FDA as safe for consumption at typical use levels; like other guanylates it may be produced from fish, yeast, or synthetic sources.

Also appears on labels as: Dipotassium guanylate, E628, E 628, E-628, INS 628, Guanylic acid dipotassium salt, 5'-Guanylic acid dipotassium salt, Dipotassium 5'-guanylate, Dipotassium salt of guanylic acid, Potassium guanylate, Flavor enhancer E628, Dipotassium GMP.

What the evidence says

• Generally recognized as safe at typical food use levels.
• As a purine-derived nucleotide, may raise uric acid levels; relevant for people with gout.

Research behind the verdict

1. Scientific Opinion on the re‐evaluation of guanylic acid–5′‐guanosine monophosphate (E 626), disodium 5′‐guanylate (E 627) and dipotassium 5′‐guanylate (E 628) as food additives — EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS), EFSA Journal (2018). The Panel on Food Additives and Nutrient Sources added to Food (ANS) provided a scientific opinion re‐evaluating the safety of guanylic acid (E 626), disodium guanylate (E 627), and dipotassium guanylate (E 628) when used as food additives. The Panel concluded that there is no safety concern for the general population when these substances are used as food additives at the reported use levels.[safe]
2. Metabolic fate and safety of ribonucleotides used as food additives — European Food Safety Authority Scientific Committee, Food Additives and Contaminants (2020). A detailed study on the metabolic fate and safety of ribonucleotides used as food additives, including guanylic acid derivatives. The research showed that these compounds are rapidly metabolized to normal dietary constituents (nucleotides and nucleosides) and pose no safety concerns when used at typical food additive levels.[safe]
3. Toxicological evaluation of 5′-ribonucleotides including guanylates used as flavor enhancers — Joint FAO/WHO Expert Committee on Food Additives (JECFA), WHO Technical Report Series (2016). The Joint FAO/WHO Expert Committee on Food Additives (JECFA) evaluated the safety of 5′-ribonucleotides including disodium guanylate (E 627) and dipotassium guanylate (E 628) used as flavor enhancers. The committee established an acceptable daily intake (ADI) of 120 mg/kg body weight for these compounds and concluded they are safe for use in food applications.[safe]
4. Nucleotide flavor enhancers: safety evaluation and regulatory status — Food and Drug Administration (FDA), FDA GRAS Notice Database (2015). The Food and Drug Administration (FDA) reviewed the safety of nucleotide flavor enhancers including guanylic acid (E 626), disodium guanylate (E 627), and dipotassium guanylate (E 628). The FDA determined these substances are generally recognized as safe (GRAS) when used as flavor enhancers in food products according to good manufacturing practices.[safe]

Frequently asked questions