Is 4-Methylpent-3-En-2-One (Mesityl Oxide) safe in cosmetics?
4-Methylpent-3-En-2-One (Mesityl Oxide) has a safety rating of "MODERATE" in our database. EU status: permitted. US status: permitted.
4-Methylpent-3-En-2-One (Mesityl Oxide)
Also known as: Mesityl oxide, Acetone, isopropylidene-, BRN 1361550, Caswell No. 547, EINECS 205-502-5 (+15 more)
4-Methylpent-3-En-2-One (Mesityl Oxide) (CAS 141-79-7) is a cosmetic cosmetic ingredient functioning as Flavouring and nutrient; Fragrance; Solvent. EU Regulation 1223/2009 status: permitted; GHS signal word DANGER. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.
View industrial chemical safety profile for CAS 141-79-7 →
Auto-generated CPSR Part A draft with source citations
Cross-Vertical Regulatory Divergence
4-Methylpent-3-En-2-One (Mesityl Oxide) is classified GHS Danger (H226, H302, H312, H315, H319, H331, H332, H335) in the chemicals database but is allowed in EU cosmetics.
Source: Cosmetics: ingredients.eu_status; Chemicals: ghs_classifications.signal_word/hazard_statement_code
Function
Flavouring and nutrient; Fragrance; Solvent
Safety Rating
MODERATE
Regulatory Status
EU EU Status
permitted
US US Status
permitted
US Notes
Not specifically restricted by FDA for cosmetic use
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for 4-Methylpent-3-En-2-One (Mesityl Oxide).
Calculate MoS for your specific formulation with the MoS Calculator.
GHS Hazard Classification
Globally Harmonized System classification per ECHA C&L inventory and ILO/WHO International Chemical Safety Cards.
Signal Word
DANGER
Pictograms
FlamFlameSkullToxicCancerHealth haz
Hazard Statements
Flammable liquid and vapour Harmful if swallowed Toxic if inhaled Causes skin and eye irritation May cause respiratory irritation May cause damage to organs through prolonged or repeated exposure May be harmful if swallowed and enters airways Harmful to aquatic life
Short-term Exposure Effects
The substance is irritating to the eyes, skin and respiratory tract. Exposure far above the OEL could cause unconsciousness. If swallowed the substance may cause vomiting and could result in aspiration pneumonitis.
Long-term Exposure Effects
The substance defats the skin, which may cause dryness or cracking. The substance may have effects on the liver, kidneys and lungs.
Routes of Exposure
The substance can be absorbed into the body by inhalation of its vapour and by ingestion.
EU CLP Annex VI Harmonized Classification
Legally binding harmonized classification per Regulation (EC) No 1272/2008 (CLP) Annex VI.
Signal Word
Warning
Pictograms
FlammableHarmful / Irritant
Hazard Class and Category
Flam. Liq. 3; Acute Tox. 4 *; Acute Tox. 4 *; Acute Tox. 4 *
Hazard Statements
- H226 Flammable liquid and vapour
- H332 Harmful if inhaled
- H312 Harmful in contact with skin
- H302 Harmful if swallowed
Specific Concentration Limits / M-factors
*
Inserted via ATP: CLP00
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
1 - 10 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No
Hazard classification: Restricted (Annex XVII)
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Flavouring and nutrient
Fragrance
Solvent
Regulatory List Membership (2)
IFRA Fragrance Transparency List
FDA Substances Added to Food (EAFUS)
Expert Verdict
Expert safety assessment and concern-level summary for 4-Methylpent-3-En-2-One (Mesityl Oxide).
Regulatory Flags
fragrance-component
ifra_fragrance
fda_food_additive
Known Synonyms
Mesityl oxide
Acetone, isopropylidene-
BRN 1361550
Caswell No. 547
EINECS 205-502-5
EPA Pesticide Chemical Code 052401
FEMA No. 3368
FEMA Number 3368
3-Isohexen-2-one
Isopropylidene acetone
2-Methyl-2-pentenone-4
4-Methyl-3-penten-2-on
4-Metil-3-penten-2-one
Mesityloxyde
Ossido di mesitile
Oxyde de mesityle
UNII-77LAC84669
(CH3)2C=CHC(=O)CH3
1-Methylpent-2-en-4-one
3-PENTEN,2-ONE,4-METHYL MESITYLOXIDE
Chemical Function
Fragrance
Flavouring and nutrient
Solvent
Regulatory Lists
IFRA Transparency
food_additive; Substances Added to Food (formerly EAFUS) (2/2019)
Europe
inert_ingredient; non_food_use; Pesticides
Australian Status
AICIS status: listed
Cross-Vertical Safety Context
Same-CAS public records found in pharmaceutical data.
SOURCE
ChEMBL / DrugCentral / FAERS
DB_PHARMA CAS match
Pharmaceutical Data
Same-CAS rows from the pharmaceutical spoke database.
ChEMBL ID
CHEMBL3185916
Frequently Asked Questions
Is 4-Methylpent-3-En-2-One (Mesityl Oxide) allowed in the EU?
4-Methylpent-3-En-2-One (Mesityl Oxide) EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.
What does 4-Methylpent-3-En-2-One (Mesityl Oxide) do in cosmetics?
4-Methylpent-3-En-2-One (Mesityl Oxide) functions as: Flavouring and nutrient; Fragrance; Solvent. It is classified as a cosmetic ingredient in our database. CAS number: 141-79-7.
Is 4-Methylpent-3-En-2-One (Mesityl Oxide) classified as hazardous under GHS?
4-Methylpent-3-En-2-One (Mesityl Oxide) carries a GHS signal word of "DANGER". Hazard statements: Flammable liquid and vapour Harmful if swallowed Toxic if inhaled Causes skin and eye irritation May cause respiratory irritation May cause damage to organs through prolonged or repeated exposure May be harmful if swallowed and enters airways Harmful to aquatic life. This classification is based on the ILO/WHO International Chemical Safety Card and ECHA C&L inventory data. Note: GHS classification applies to the pure substance — at cosmetic use concentrations, hazard thresholds may not be met.
Is 4-Methylpent-3-En-2-One (Mesityl Oxide) used outside cosmetics?
4-Methylpent-3-En-2-One (Mesityl Oxide) also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Does 4-Methylpent-3-En-2-One (Mesityl Oxide) have different safety status in cosmetics vs industrial chemicals?
4-Methylpent-3-En-2-One (Mesityl Oxide) is classified GHS Danger (H226, H302, H312, H315, H319, H331, H332, H335) in the chemicals database but is allowed in EU cosmetics.
Compliance Tools
Check 4-Methylpent-3-En-2-One (Mesityl Oxide) compliance across multiple jurisdictions:
Ingredient Decoder
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Substance Compliance
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MoS Calculator
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Heavy Metal Limits
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