Ingredient

Methylchloroisothiazolinone

Preservative usually paired with methylisothiazolinone (MCI/MI). Strong sensitizer.

Methylchloroisothiazolinone is a potent biocide almost always paired with methylisothiazolinone in a 3:1 ratio (Kathon CG) for rinse-off preservation. Concentrations are kept extremely low (≤0.00075%) to minimise sensitisation.

Also known as

MCIKathon CGChloromethylisothiazolinone5-Chloro-2-methyl-4-isothiazolin-3-oneKathon

Categories

preservative
Pore Clogging

Low concern

Methylchloroisothiazolinone has a low comedogenic rating and is unlikely to clog pores.

Fungal Acne

Low concern

Methylchloroisothiazolinone is considered safe for fungal-acne-prone skin.

Pregnancy

Some caution

Methylchloroisothiazolinone may require caution during pregnancy. Consult your doctor. Reason: high-sensitising preservative with restricted use.

Irritation

Higher concern

Methylchloroisothiazolinone is commonly associated with skin irritation or sensitisation. Reason: high-sensitising preservative linked to allergic contact dermatitis.

Common Questions

What is Methylchloroisothiazolinone used for?
Preservative usually paired with methylisothiazolinone (MCI/MI). Strong sensitizer.
Can Methylchloroisothiazolinone clog pores?
Methylchloroisothiazolinone has a low comedogenic rating and is unlikely to clog pores.
Is Methylchloroisothiazolinone fungal acne safe?
Methylchloroisothiazolinone is considered safe for fungal-acne-prone skin.
Is Methylchloroisothiazolinone commonly irritating?
Methylchloroisothiazolinone is commonly associated with skin irritation or sensitisation.

Educational purposes only. Always consult a dermatologist for personalised guidance.