MIBK (methyl isobutyl ketone)
Official label name (INCI name, EU glossary of cosmetic ingredient names), No 16700
- Prohibited in cosmetics (Annex II)
MIBK (methyl isobutyl ketone): Prohibited in cosmetics (Annex II, entry 1689), under Regulation (EC) No 1223/2009.
In plain words
What it is used for
Functions declared by manufacturers:
Denaturant: renders cosmetics unpalatable. Mostly added to cosmetics containing ethyl alcohol.
Solvent: dissolves other substances.
Perfuming.
What the rules say
It is prohibited to use it in a cosmetic product sold in the European Union, whatever the dose. If it appears on the ingredient list of a recent product, this needs checking: the record may be old or wrong, or the product intended for another market.
Hazard and risk
The CLP Regulation classifies this substance as carcinogenic, category 2 (suspected effect, without enough evidence for a higher category).
This classification describes what the substance can cause (a hazard), not what happens when using a product (a risk): the risk depends on the dose, the form and the route of exposure (skin, inhalation, ingestion).
Already prohibited in cosmetics (Annex II).
The text of the annexes
Prohibited in cosmetics
CosIng links the name MIBK to this Annex II entry.
- Entry
- Annex II, No 1689
- Substance
- 4-methylpentan-2-one; isobutyl methyl ketone (MIBK)
- CAS
- 108-10-1
- EC
- 203-550-1
- CMR
- Carcinogenic Cat. 2()
Dates in the act (3)
- Entry into force on 6 October 2022
- Application from 17 December 2022
Article 1 shall apply from 17 December 2022.
- Entry into force on 17 December 2022
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
- 35359
- CAS (according to CosIng)
- 108-10-1
- EC (according to CosIng)
- 203-550-1
- Declared functions
- Denaturant, Solvent, Perfuming
- Wikidata
- Q418104
- PubChem
- 7909
- ECHA InfoCard
- 100.003.228
- InChIKey
- NTIZESTWPVYFNL-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.
4-methylpentan-2-one; isobutyl methyl ketone
CMR Carc. 2
- Hazard classes
- Flam. Liq. 2
Carc. 2
Acute Tox. 4
STOT SE 3
Eye Irrit. 2 - Hazard statements
- H225 H351 H332 H336 H319
Already prohibited in cosmetics (Annex II).
Elsewhere in the world
Information on other jurisdictions. What is covered, and what is not yet.
United Kingdom (Great Britain)
- Prohibited in cosmetics (Annex II)
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.
Glossary: Commission Implementing Decision (EU) 2025/1175. Page updated on 21 October 2026.