METHYLCHLOROISOTHIAZOLINONE is graded C (Moderate) by Expert·ING, based on COSING, FDA regulatory data. It is restricted under Sephora Clean (Prohibited).
METHYLCHLOROISOTHIAZOLINONE
Safety grade: C
This is a synthetic chemical preservative that kills bacteria and fungi to keep cosmetic products fresh and safe. It prevents mold and microbial growth that could otherwise spoil your product.
It preserves cosmetic products by preventing the growth of microorganisms, extending shelf life and maintaining product safety.
Graded using: COSING, FDA.
- Health Canada — Restricted
- Sephora Clean — Prohibited
Last verified: May 26, 2026
Safer alternatives to METHYLCHLOROISOTHIAZOLINONE
- PHENOXYETHANOL — Grade B**. Broad-spectrum preservative preventing microbial growth in cosmetics.
- POTASSIUM SORBATE — Grade B. Preservative system effective against bacteria and fungi in products.
- CHLORPHENESIN — Grade B. Antimicrobial preservative preventing microbial spoilage in formulations.
- SORBIC ACID — Grade B. Preservative preventing growth of mold, yeast, and bacteria.
Other Preservative ingredients
- SODIUM BENZOATE — Grade C
- BENZYL ALCOHOL — Grade C**
- BENZOIC ACID — Grade C**
- METHYLISOTHIAZOLINONE — Grade C
- METHYLPARABEN — Grade C
- SALICYLIC ACID — Grade C**