AMMONIUM SULFITE is graded C (Moderate) by Expert·ING, based on COSING regulatory data. It is restricted under EU COSING — AnnexIII-SAFETY-.
AMMONIUM SULFITE
Safety grade: C
This preservative is permitted in EU cosmetics up to a maximum concentration under EU Cosmetics Regulation (EC) No 1223/2009. To be sold legally in the EU or UK, a product must stay within this limit.
This ingredient works to relax or straighten hair by breaking chemical bonds, while also protecting cosmetic formulations from degradation caused by oxidation and extending shelf life.
Graded using: COSING.
- EU COSING — Restricted
- EU COSING — Restricted use
Last verified: June 9, 2026
Safer alternatives to AMMONIUM SULFITE
- SODIUM METABISULFITE — Grade B. Reducing agent and antioxidant preservative for hair straightening formulas
- THIOGLYCERIN — Grade A. Reducing agent for hair waving/straightening with keratolytic properties
- STANNOUS CHLORIDE — Grade A**. Reducing agent used in hair relaxation and straightening treatments
Other Preservative ingredients
- SODIUM BENZOATE — Grade C
- PHENOXYETHANOL — Grade B**
- BENZYL ALCOHOL — Grade C**
- POTASSIUM SORBATE — Grade B
- BENZOIC ACID — Grade C**
- METHYLISOTHIAZOLINONE — Grade C
- METHYLPARABEN — Grade C
- SALICYLIC ACID — Grade C**