Isopentane
AKA “2-Methylbutane, Isoamylhydride, Butane, iso-Pentane, 2-Trimethylethane, Dimethylethylmethane, Ethyldimethylmethane, methylbutane”
Synthetic
Ingredient Facts
Isopentane
AKA: 2-Methylbutane, Isoamylhydride, Butane, Iso-Pentane, 2-Trimethylethane, Dimethylethylmethane, Ethyldimethylmethane, Methylbutane
Synthetic · Propellant · EWG: 4
Synthetic
Solvent
Synthetic
Clean
A lightweight propellant that helps dispense the product evenly from a spray bottle while keeping the formula smooth and consistent.
Solubility less than 1 mg/mL at 73 °F (NTP, 1992)
Formula
C5H12
Mol. Weight
72.15
CAS #
78-78-4
Form
Powder
State
Watery colorless liquid with a gasoline-like odor. Floats on water. Flammable, irritating vapor is produced. Boiling point is 82 °F. (USCG, 1999)
See origin →
Functions
Propellant
Solvent
Dissolves other ingredients so they distribute evenly in the formula. Often the invisible "base" everything else is mixed into.
Viscosity Controlling
Dispenses Product
Dissolves Ingredients
Controls Viscosity
Propels product from container
Dissolves other ingredients
Controls product thickness
Traditional Use
A synthetic hydrocarbon solvent developed in the 20th century for cosmetic formulations. Used for its volatile properties to improve product spreadability and quick-drying characteristics.
Skin Types
●all-skin-types
Best For
General
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
Final Report of the Safety Assessment of Isobutane, Isopentane, n-Butane, and Propane
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
Isobutane, Butane, Isopentane and Propane
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
1,2-Butanediol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
1,4-Butanediol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
2,3-Butanediol
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR