Methylchloroisothiazolinone

Methylchloroisothiazolinone is a preservative used in cosmetics and personal care products to prevent the growth of bacteria, yeasts, and molds. It is often used in combination with methylisothiazolinone. This ingredient helps to ensure product safety and extend shelf life by inhibiting microbial contamination.

BenefitNone 0 / 4

RiskSerious 3.5 / 4

Sensitization i4 / 4

Risk of allergic contact dermatitis or immune-based reactions. Fragrance allergens, preservatives, botanicals, and some dyes may score here.

Irritation i3 / 4

Risk of short-term irritation — stinging, burning, dryness, redness, or discomfort. Common for strong actives, acids, retinoids, fragrances, and harsh surfactants.

Rated by SpottyLabs' ingredient methodology, independent of brands.

Things to watch

• Can cause skin sensitization and allergic reactions
• High risk of contact dermatitis

Products with Methylchloroisothiazolinone

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Frequently asked questions

What is Methylchloroisothiazolinone used for in cosmetics?

Methylchloroisothiazolinone is used as a preservative in cosmetics and personal care products. Its primary function is to prevent the growth of harmful microorganisms like bacteria and fungi, ensuring the product remains safe and effective for its intended shelf life.

Is Methylchloroisothiazolinone safe for sensitive skin?

Methylchloroisothiazolinone is a known sensitizer and can cause allergic reactions, especially in individuals with sensitive skin or a history of eczema. Due to its high potential for sensitization, its use in leave-on products is restricted or prohibited in many regions.