Staff Answer
May 29, 2026 - 02:21 PM
Both are specially denatured alcohols, but with different denaturants and different intended uses. SDA 40B (tert-butyl alcohol + denatonium benzoate) is approved for cosmetic, fragrance, and topical OTC use because the denaturants don't affect skin feel or finished-product properties. SDA 3C (isopropyl alcohol) is more common in industrial cleaning, solvent recovery, and bulk processing where skin contact isn't a factor. For perfumery and cosmetics, 40B is the standard.
