Compoatlas

METHYLISOTHIAZOLINONE

Official label name (INCI name, EU glossary of cosmetic ingredient names), No 16644

METHYLISOTHIAZOLINONE: Preservative allowed under conditions, with limits depending on the product type (Annex V, entry 39), under Regulation (EC) No 1223/2009.

In plain words

What it is used for

Functions declared by manufacturers:

Preservative: inhibits primarily the development of micro-organisms in cosmetics.

What the rules say

An ingredient can be used as a preservative only if it appears on the list of Annex V. <function plain_language.<locals>.name at 0x7f7805a94720> is on it with a maximum concentration and for some product types only.

The text of the annexes

Preservative allowed under conditions

This entry covers the same substance as METHYLISOTHIAZOLINONE (same CAS number in the CosIng inventory): its conditions apply.

Entry
Annex V, No 39
Substance
Mixture of 5-Chloro-2-methyl-isothiazol-3(2H)-one and 2-Methylisothiazol-3(2H)-one with magnesium chloride and magnesium nitrate
Glossary names
METHYLCHLOROISOTHIAZOLINONE AND METHYLISOTHIAZOLINONE
CAS
26172-55-4, 2682-20-4, 55965-84-9
EC
247-500-7, 220-239-6
Product type
Rinse-off
Maximum concentration
0.0015% (of a mixture in the ratio 3:1 of 5-Chloro-2-methyl-isothiazol-3(2H)-one and 2-Methylisothiazol-3(2H)-one
Dates in the act (5)
  • Entry into force on 16 October 2014
  • Application from 16 July 2015
    It shall apply from 16 July 2015.
  • Entry into force on 16 July 2015
  • Placing on the market from 16 July 2015
    From 16 July 2015 only cosmetic products which comply with Regulation (EC) No 1223/2009 as amended by this Regulation shall be placed on the Union market
  • Making available from 16 April 2016
    From 16 April 2016 only cosmetic products which comply with Regulation (EC) No 1223/2009 as amended by this Regulation shall be made available on the Union market

Excerpts from the English text published in the Official Journal. A date may concern only some substances of the act: the excerpt says so.

Preservative allowed under conditions

Entry
Annex V, No 57
Substance
2-Methyl-2H-isothiazol-3-one
Glossary names
METHYLISOTHIAZOLINONE
CAS
2682-20-4
EC
220-239-6
Maximum concentration
0,0015 % Rinse-off products
Dates in the act (3)
  • Entry into force on 27 July 2017
  • Placing on the market from 27 January 2018
    From 27 January 2018 only cosmetic products which comply with this Regulation shall be placed on the Union market
  • Making available from 27 April 2018
    From 27 April 2018 only cosmetic products which comply with this Regulation shall be made available on the Union market

Excerpts from the English text published in the Official Journal. A date may concern only some substances of the act: the excerpt says so.

Identity

CosIng identifier
35341
CAS (according to CosIng)
2682-20-4
EC (according to CosIng)
220-239-6
Declared functions
Preservative
Wikidata
Q423870
PubChem
39800
ECHA InfoCard
100.018.399
InChIKey
BEGLCMHJXHIJLR-UHFFFAOYSA-N

Classified hazard (CLP Regulation)

A classification describes an intrinsic hazard, not a risk: the risk depends on the dose, the form and the exposure.

2-methylisothiazol-3(2H)-one

No harmonised CMR classification

Hazard classes
Acute Tox. 2
Acute Tox. 3
Acute Tox. 3
Skin Corr. 1B
Eye Dam. 1
Skin Sens. 1A
Aquatic Acute 1
Aquatic Chronic 1
Hazard statements
H330 H311 H301 H314 H318 H317 H400 H410

EU product alerts (Safety Gate)

136 alerts on cosmetic products cite this name in their hazard description. An alert targets a specific product, not the ingredient itself; each alert states the reason (prohibited substance, limit exceeded, missing labelling, and so on).

  • 28 August 2026: Sun protection cream, Maycheer, Germany (“Serious risk”) alert
  • 8 May 2026: Hair conditioner, Hairdreams, Austria (“Serious risk”) alert
  • 10 April 2026: Hair conditioner, Hairdreams, Germany (“Serious risk”) alert
  • 26 December 2025: Body lotion, ISOLDA, Czechia (“Serious risk”) alert
  • 26 December 2025: Body lotion, ISOLDA, Czechia (“Serious risk”) alert
  • 12 December 2025: Hair and body cream, Cielo Alto, Italy (“Serious risk”) alert
  • 7 November 2025: Toy make-up set, United Kingdom in respect of Northern Ireland (“Serious risk”) alert
  • 24 October 2025: Hair care product, SKALA, France (“Serious risk”) alert
  • 12 September 2025: Baby shampoo, Makari de Suisse, France (“Serious risk”) alert
  • 4 April 2025: Hair wax, La Gardenia, Italy (“Serious risk”) alert

Elsewhere in the world

Information on other jurisdictions. What is covered, and what is not yet.

United Kingdom (Great Britain)

  • Preservative allowed under conditions (Annex V)

Same entries as in the European Union. Conditions (concentrations, warnings) may differ: they are not compared here.

Switzerland

Regulation (EC) No 1223/2009 applies in Switzerland (Article 54 of the Ordinance on Foodstuffs and Utility Articles).

United States, federal rules

None of the integrated sections of the federal code (21 CFR 700.11 to 700.27 and 250.250) targets this name. The FDA does not publish a list of allowed ingredients.

South Korea

  • Restricted: 메칠이소치아졸리논 (METHYLISOTHIAZOLINONE)

    별표 2, 보존제 성분 (preservatives), entry 9, page 2. Limit: 사용 후 씻어내는 제품에 0.0015% (단,메칠클로로이소 치아졸리논과 메칠이소치아졸리 논 혼합물과 병행 사용 금지). Conditions (source text, in Korean): 비고: 기타 제품에는 사용금지

Australia

  • Subject to conditions (threshold, labelling or packaging): METHYLISOTHIAZOLINONE

    Poisons Standard, Schedule 6 (cosmetic entries), page 268. Thresholds cited: 0.0015% or less | 0.1% or less. Conditions (source text): except: | (a) in rinse-off cosmetic preparations or therapeutic goods intended for topical rinse-off application containing 0.0015% or less of methylisothiazolinone; or | (b) in other preparations that are not intended for direct application to the skin containing 0.1% or less of methylisothiazolinone

Brazil

  • Allowed under conditions: 2-metil-4-isotiazolina-3-ona (METHYLISOTHIAZOLINONE)

    RDC 528/2021, Anexo (allowed preservatives), entry 57, page 5. Limit: 0,0015% em produtos que se enxáguem.. Conditions (source text, in Portuguese): LIMITAÇÕES: -Proibido em produtos que não se enxáguem (incluindo os lenços umedecidos). -A utilização da mistura de methylchloroisothiazolinone e methylisothiazolinone é incompatível com a utilização de methylisothiazolinone sozinha em um mesmo produto.

  • Allowed under conditions: Mistura de 5-cloro-2-metil-4-isotiazolina-3-ona e 2-metil-4-isotiazolina-3-ona com cloreto de magnésio e nitrato de magnésio (3:1) (METHYLCHLOROISOTHIAZOLINONE e METHYLISOTHIAZOLINONE)

    RDC 528/2021, Anexo (allowed preservatives), entry 35, page 4. Limit: 0,0015% (de uma mistura em proporções 3:1 de 5-Chloro-2-methyl-isothiazol-3(2H)-one e 2-Methylisothiazol-3 (2H)-one) em produtos que se enxáguem.. Conditions (source text, in Portuguese): LIMITAÇÕES: -Proibido em produtos que não se enxáguem (incluindo os lenços umedecidos). -A utilização da mistura de methylchloroisothiazolinone e methylisothiazolinone é incompatível com a utilização de methylisothiazolinone sozinha em um mesmo produto.

Recorded cosmetics that contain it

675 recorded products list it, according to Open Beauty Facts contributors. Records are dated: the formula may have changed. See the list (page in French).

Glossary: Commission Implementing Decision (EU) 2025/1175. Page updated on 21 October 2026.