Isobutane

AKA: 2-Methylpropane, 75-28-5, Trimethylmethane, 1, 1-Dimethylethane, Iso-butane, R 600a, Caswell No. 503A, R-600a, HSDB 608
Synthetic
Not Clean
Isobutane, less than 0.1% w/w butadiene
Solubility Slight (NIOSH, 2024)
Formula
C4H10
Mol. Weight
58.12
CAS #
75-28-5
Form
Liquid
State
Isobutane is a colorless gas with a faint petroleum-like odor. It is shipped as a liquefied gas under its vapor pressure. Contact with the liquid can cause frostbite. It is easily ignited. The vapors
Functions
Propellant
Dispenses Product
Locks In Moisture
Propels product from container
Traditional Use
A hydrocarbon gas synthesized from petroleum in the 20th century. Adopted by the cosmetics industry as a propellant in aerosol sprays and foams, replacing earlier flammable propellants.
EWG
7
CIR
Safe as used
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Status
USApermitted
EUrestricted
JAPANrestricted
CANADArestricted
🧂Conflict of interest.
Skin Types
all-skin-types
Best For
General
Pregnancy & Breastfeeding Safe
Yes
The paper trail
🔬Peer-reviewed1 paper
⚖️Regulatory1 listing
🛡️Safety-assessed2 reviews
Counts, not a verdict. A listing isn't a study. The trail, you decide.
Verified Jun 2026 · 🧪 = conflict
Data: PubChem · CosIng · EWG · CIR