Is Direct Red 81 vegan?
Direct Red 81
Vegan
Vegan
Vegetarian
Vegetarian
Sirius Red 4B, also known as Chlorantine Fast Red 5B or Direct Red 81, is a synthetic azo dye used in histological staining applications. It is listed in the Colour Index as CI 28160.
| Also known as | 2-Naphthalenesulfonic acid, 7-(benzoylamino)-4-hydroxy-3-[[4-[(4-sulfophenyl)azo]phenyl]azo]-, Chlorantine Fast Red 5B, Direct Red 81, Disodium 7-benzamido-4-hydroxy-3-[[4-[(4-sulphonatophenyl)azo]phenyl]azo]naphthalene-2-sulphonate (CI 28160) |
|---|---|
| INCI name | Direct Red 81 |
| CAS number | 2610-11-9 |
| EC number | 220-028-9 |
| CI number | CI 28160 |
| CosIng ID | 33568 |
| Last reviewed | 3 June 2026 |
An ingredient is considered vegan if it contains no animal-derived components at any point in its production.
Classifications are made to the best of our knowledge based on available scientific and regulatory sources. We cannot guarantee the accuracy of every entry, errors in the sources we draw from can always occur. This tool also cannot account for cross-contamination, which depends entirely on individual suppliers and producers. If you believe a classification is incorrect, you can report an issue.
