Methylisothiazolinone
Decode Label flags Methylisothiazolinone as a high concern in cosmetics and personal care (skin irritant). It appears in 5 of the 893 published products we have analysed (0.6%).
The concern
Preservative — potent contact sensitiser; banned from EU leave-on products
MI and its chlorinated partner MCI are preservatives and recognised contact sensitisers. After MI replaced parabens in many products, European dermatology clinics recorded a sharp rise in contact allergy to it. Contact allergy, once acquired, is usually long-lasting, so people already sensitised to MI are advised to avoid it. EU rules ban MI from leave-on cosmetics (since 2017) and limit it to 15 ppm in rinse-off products. Whether a particular product causes a reaction depends on the person, the concentration and the contact time, which the label alone cannot show.
Most relevant to
Cited authority
EU Regulation 2017/1224; SCCS Opinion SCCS/1521/13; British Journal of Dermatology (MI epidemic)
Linked sources: EU-CosIng →
How common it is in this catalogue
Measured across every product Decode Label has analysed — not estimated, and not taken from anyone else's dataset.
By category
Regulatory position
From the published regulation itself. Each row links to its source.
| Authority | Status | Reference | Scope / limit | Source |
|---|---|---|---|---|
| EU-CosIng | Permitted | Annex V 57 | — max 0,0015 % Rinse-off products | View → |
Identity
- Canonical name
- 2-Methyl-2H-isothiazol-3-one
- INCI name
- METHYLISOTHIAZOLINONE
- CAS number
- 2682-20-4
- EC number
- 220-239-6
Also appears on labels as
Questions
Is Methylisothiazolinone safe?
The concern is cited to EU Regulation 2017/1224; SCCS Opinion SCCS/1521/13; British Journal of Dermatology (MI epidemic). Why it is flagged: Preservative — potent contact sensitiser; banned from EU leave-on products. Decode Label treats it as a high concern in cosmetics and personal care. It appears in 5 of the 893 published products we have analysed (0.6%).
How common is Methylisothiazolinone in Indian packaged products?
Decode Label found Methylisothiazolinone in 5 of 893 published products (0.6%), most often in Haircare, Skincare.
Is Methylisothiazolinone restricted or banned anywhere?
Under the EU Cosmetics Regulation (EC) No 1223/2009 (CosIng), Methylisothiazolinone has 1 permitted entry. Each is shown with its annex reference and a link to the source in the Regulatory position table.
Who should be most careful with Methylisothiazolinone?
People prone to allergies; People with eczema; People with sensitive skin; Children.
Products containing Methylisothiazolinone
5 published products, each with its own full analysis.
Related ingredients
Other entries in the register with the same kind of concern.
Method and limits
- Prevalence counts published products whose decoded ingredient list matches this substance or one of its label synonyms, using the same matching the score itself uses. It describes our catalogue of 893 products, not the Indian market as a whole.
- Presence is not dose. An ingredient list gives order, not quantity, unless the pack declares a percentage. Nothing here estimates how much of this substance any product contains.
- A classification is not a verdict on a product. An agency classifies a substance under defined conditions of exposure; whether that matters in a given food or cosmetic depends on route, concentration and use.
- Last updated. This register entry was last changed on 3 October 2026.
- Corrections. Every figure here is reproducible from the sources named. If something is wrong, tell us and we will correct it and say what changed.