MIBK
AKA “4-Methyl-2-pentanone, METHYL ISOBUTYL KETONE, 4-Methylpentan-2-one, 108-10-1, Isopropylacetone, Isobutyl methyl ketone, Hexone, 2-Pentanone, 4-methyl-, 2-Methyl-4-pentanone
Ingredient
Ingredient Facts
MIBK
AKA: 4-Methyl-2-pentanone, METHYL ISOBUTYL KETONE, 4-Methylpentan-2-one, 108-10-1, Isopropylacetone, Isobutyl methyl ketone, Hexone, 2-Pentanone, 4-methyl-, 2-Methyl-4-pentanone
Ingredient · Denaturant · EWG: 4
Synthetic
Fragrance
Solvent
Not Clean
Methyl isobutyl ketone is used as a solvent for gums, resins, paints, varnishes, lacquers, and nitrocellulose. Acute (short-term) exposure to methyl isobutyl ketone may irritate the eyes and mucous membranes, and cause weakness, headache, nausea, lightheadedness, vomiting, dizziness, incoordination, narcosis in humans. Chronic (long-term) occupational exposure to methyl isobutyl ketone has been observed to cause nausea, headache, burning in the eyes, weakness, insomnia, intestinal pain, and slight enlargement of the liver in humans. Lethargy and kidney and liver effects have been observed in rats and mice chronically exposed by gavage (experimentally placing the chemical in the stomach), ingestion, and inhalation. EPA has classified methyl isobutyl ketone as a Group D, not classifiable as to human carcinogenicity.
Solubility 1 to 5 mg/mL at 70 °F (NTP, 1992)
Formula
C6H12O
Mol. Weight
100.16
CAS #
108-10-1
Form
Liquid
State
Methyl isobutyl ketone appears as a clear colorless liquid with a pleasant odor. Flash point 73 °F. Less dense than water. Vapors heavier than air.
See origin →
Functions
Denaturant
Perfuming
Added for scent. Can be natural or synthetic. Common irritant and allergen — one of the top reasons people react to products.
Solvent
Dissolves other ingredients so they distribute evenly in the formula. Often the invisible "base" everything else is mixed into.
Makes Alcohol Undrinkable
Adds Fragrance
Dissolves Ingredients
Locks In Moisture
Adds pleasant scent
Dissolves other ingredients
Traditional Use
Methyl isobutyl ketone, a synthetic solvent developed in the early 20th century. Used in cosmetics manufacturing and historically in nail products, largely phased out due to toxicity concerns.
Skin Types
all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
No
EWG
4
CIR
Safe as used
Pregnancy
No
CIR Safety Findings
medical-approval
all-shades-safe
Moderate Irritant
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
Verified Jun 2026
Data: PubChem · CosIng · EWG · CIR