METHYLISOTHIAZOLINONE is graded C (Moderate) by Expert·ING, based on COSING, FDA regulatory data. It is restricted under Sephora Clean (Prohibited).
METHYLISOTHIAZOLINONE
MIT
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 preservative protects cosmetic products from spoiling and becoming unsafe by killing or preventing the growth of microorganisms that could cause deterioration or pose health risks.
Graded using: COSING, FDA.
- Health Canada — Restricted
- Sephora Clean — Prohibited
- EU COSING — Restricted use
Last verified: June 9, 2026
Safer alternatives to METHYLISOTHIAZOLINONE
- PHENOXYETHANOL — Grade B**. Broad-spectrum preservative that prevents microbial growth in cosmetics.
- POTASSIUM SORBATE — Grade B. Natural preservative that inhibits bacteria and mold in formulations.
- CHLORPHENESIN — Grade B. Antimicrobial preservative that prevents product spoilage and degradation.
- SORBIC ACID — Grade B. Natural preservative that stops bacterial and fungal growth in products.
Other Preservative ingredients
- SODIUM BENZOATE — Grade C
- BENZYL ALCOHOL — Grade C**
- BENZOIC ACID — Grade C**
- METHYLPARABEN — Grade C
- SALICYLIC ACID — Grade C**
- METHYLCHLOROISOTHIAZOLINONE — Grade C