Guanylic Acid
The short version
The free-acid form of the umami nucleotide — the parent of disodium and dipotassium guanylates.
It's widely considered safe at the amounts used in food, so we mark it green. The Safety section below has the details.
Where it comes from
Produced by enzymatic hydrolysis of yeast RNA, followed by chromatographic separation of the guanosine fraction. The natural umami nucleotide of dried mushrooms, particularly shiitake.
How it's used
Less common than the sodium salt (E627) — when used, primarily in dry seasoning blends where the free-acid form is paired with bicarbonate for in-situ salt generation, or in low-sodium formulations.
Safety profile
ADI not specified (combined nucleotides). Endogenous purine nucleotide. May modestly raise uric acid in susceptible individuals (gout); the dietary contribution is small compared with high-purine foods.
Physical & chemical properties
White to off-white crystalline powder. Sparingly soluble in water (more soluble as the sodium salt). Heat-stable.
Regulation worldwide
Permitted globally with maximum-use limits per category.
Educational information only. Not medical or dietary advice.