Propane

Propane is a gas derived from petroleum and natural gas. In cosmetics, its only used as an aerosol propellant (it pushes your product out of the can when you press the nozzle).

That's why you'll find it in hair sprays, dry shampoos, deodorants, mousses, shaving foams, and sunscreen sprays.

It is volatile, meaning it only remains on skin for less than 10 seconds before evaporating. It doesn't really linger long enough on skin to act as a skincare ingredient in any meaningful way.

Hairspray concentrations are between 6-17%.

The CIR Expert Panel concluded it to be safe as a cosmetic ingredient under present concentration and usage.