Guanylic acid, 5'-
GUANYLIC ACID, 5'- · 626INS 626
Used as a flavour enhancer.
Guanylic acid is a savoury flavour enhancer, the mushroom counterpart to inosinate. Dried shiitake are rich in it, which is why drying mushrooms makes them taste more intensely of themselves than fresh ones do.
Where it is and isn’t permitted
| Jurisdiction | Status | Scope and limits | Citation |
|---|---|---|---|
| United States | Not listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited. | ||
| Codex Alimentarius | Permitted, with conditions | 1 food category no numerical limit (good manufacturing practice) | CXS 192-1995 Table Three, INS 626and 1 further provisionretrieved 2026-09-07 |
What it is made from
Produced by bacterial fermentation or by hydrolysing yeast RNA. It occurs naturally in dried mushrooms.
- Vegan status depends on the source
- Vegetarian status depends on the source
- May raise a halal question
- May raise a kosher question
This is not an omission. What this additive is made from is not fixed — depending on the manufacturer it may be plant, animal or microbial in origin, nobody is required to say which, and the same product can change source between production runs. Ask the manufacturer if it matters to you; a label cannot answer it.
Every name it appears under
2 recorded names. A label may use any of them.
INS number
- 626
Other names
- GUANYLIC ACID, 5'-
Hazard reference values
No reference value for this substance in the sources we hold.
Evidence and how bodies read it
Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.
Sources for this page
- gsfa retrieved 2026-09-07
Full licence terms and publisher details on Sources. How this page is built and updated: Method.
Machine-readable:/api/v1/additives/guanylic-acid-5.json