Cosmetic ingredient dictionary
Methylchloroisothiazolinone in cosmetics: what it is and what it does
Methylchloroisothiazolinone is a cosmetic ingredient that keeps the product from spoiling. The EU lists it as an allowed preservative, with a maximum amount. Open Beauty Facts finds it in 780 products, most often shampoos.
By Bravoora teamUpdated Sources checked 3 sourcesHow we check
What does Methylchloroisothiazolinone do in a product?
In a cosmetic product, Methylchloroisothiazolinone keeps the product from spoiling. The EU’s CosIng database lists this job for it: preservative.
What other names and numbers does Methylchloroisothiazolinone have?
- CAS number
- 26172-55-4
- EC number
- 247-500-7
- CosIng reference
- 35333
Is Methylchloroisothiazolinone restricted in the EU?
It is allowed, on a list with limits. The EU lists it as an allowed preservative, with a maximum amount (Annex V of Regulation 1223/2009, entry 39).
The annex entry sets the exact limits, the products it may be used in and any warning the label must carry.
Which products contain Methylchloroisothiazolinone?
Open Beauty Facts finds Methylchloroisothiazolinone in the ingredient lists of 780 of the 22,021 products it has a list for, most often shampoos, hair care and anti-dandruff shampoos.
Products with it, by country of sale: France 200 · United States 124 · Australia 108 · Spain 64.
Counted on 13 October 2026 from Open Beauty Facts, which volunteers fill from real packs: it shows where Methylchloroisothiazolinone turns up, not how much of the market it is.
Bravoora reads this ingredient for everyone you shop for: an allergy or intolerance, a vegan or vegetarian diet, a calorie or protein goal, and the labels on supplements and skincare too. Build a profile · For dermatologists, dietitians and doctors
Sources
The job, the description and the EU annex entry are CosIng’s; the fragrance allergens are the EU Annex III names Bravoora’s label checker reads; the product counts are Open Beauty Facts’.
- European Commission: CosIng cosmetic ingredient database (functions, description, EU annex entry)
- Open Beauty Facts: product database, 77,506 products, read 13 October 2026, ODbL
- EU Regulation 1223/2009 on cosmetic products (the annexes)
Contains information from Open Beauty Facts, which is made available here under the Open Database License (ODbL). Read the licence · Download this dictionary’s data · How we check
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