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Isobutane in skincare
Pressurized gas propellant in aerosol cans; extremely flammable; leaves the product on dispensing. No skin contact concern.
Found in pressurized aerosol products (shaving foam cans, dry shampoos, hairsprays, aerosol sunscreens) used AM and PM. The isobutane itself leaves the product upon dispensing. It is not a skin-contact ingredient. Primary safety concern is flammability. Keep aerosol products away from heat sources and open flames. Do not use near a lit candle or cigarette.
What it is
Isobutane (2-methylpropane) is a liquefied petroleum gas used as a propellant in pressurized aerosol cosmetic products. Shaving foam, dry shampoo, hairspray, aerosol sunscreen, and deodorant. It provides the pressure to expel product from the can and is rapidly volatilized upon dispensing, so it does not remain on skin or hair. Toxicologically, isobutane is not considered harmful in the concentrations and routes of exposure encountered in normal cosmetic use. The primary and significant safety concern is extreme flammability (flash point: -83°C). Aerosol products containing isobutane can ignite near open flames, causing burns or fires. FDA regulates aerosol propellants; isobutane is approved for cosmetic use. Often used in combination with propane and butane for optimal pressure profiles. No skin absorption, sensitization, or systemic toxicity concerns at cosmetic use levels.
The facts
| Category | Aerosol Propellant |
| Typical use | Morning and evening |
| Concentration YARAI treats as a full dose | 100% |
| EU Cosmetics Regulation annex | II |
| EU status | prohibited |
Why the amount matters, not just the presence
Most ingredient checkers tell you whether something is in the bottle. That is a smaller question than it sounds. Isobutane at 100% and isobutane at a trace level are not the same ingredient in any way that affects your skin.
An ingredient list is ordered by quantity, so position carries real information. YARAI reads that position and scores accordingly, which is why the same ingredient can land differently in two different products.
The honest limit: a list gives order, not percentages. Estimating concentration from position is an estimate. It is a better estimate than ignoring position, and it is still an estimate. We would rather tell you that than let a number look more certain than it is.
Regulatory status
Prohibited in EU cosmetics (CosIng Annex II).
Common questions
What does isobutane do in a skincare product?
Pressurized gas propellant in aerosol cans; extremely flammable; leaves the product on dispensing. No skin contact concern.
How much isobutane should a product contain?
YARAI treats 100% as a full dose for this ingredient. Below that, the ingredient is present but is scored as contributing less. An ingredient list gives you the order of ingredients, not their percentages, so this is an estimate read from position rather than a measurement.
When should I use isobutane?
Found in pressurized aerosol products (shaving foam cans, dry shampoos, hairsprays, aerosol sunscreens) used AM and PM. The isobutane itself leaves the product upon dispensing. It is not a skin-contact ingredient. Primary safety concern is flammability. Keep aerosol products away from heat sources and open flames. Do not use near a lit candle or cigarette.
Check your own products
Point your camera at a product. YARAI identifies it from the label, finds that product's full ingredient list from published sources, and scores it. No barcode and no box needed, which is how it handles imported and small-brand products.
Concern level, category and thresholds on this page are read directly from the same data the YARAI app scores with, so this page and the app cannot disagree. EU figures cite Regulation (EC) No 1223/2009. Last built 2026-09-09. Nothing here is medical advice.