SODIUM SULFITE is graded C (Moderate) by Expert·ING, based on COSING, FDA regulatory data. It is restricted under EU COSING — AnnexIII-SAFETY-.
SODIUM 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.
In hair care products, sodium sulfite acts as a reducing agent to chemically relax or straighten hair by altering its structure, and it serves as a preservative to prevent microbial growth and extend product shelf life.
Graded using: COSING, FDA.
- EU COSING — Restricted
- EU COSING — Restricted use
Last verified: June 9, 2026
Safer alternatives to SODIUM SULFITE
- SODIUM METABISULFITE — Grade B. Reducing agent for hair straightening; preservative alternative to sodium sulfite.
- THIOGLYCERIN — Grade A. Reducing agent for hair waving/straightening with chemical hair-relaxing properties.
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**