What it is
Isododecane is a branched hydrocarbon (isoparaffin) that serves as a solvent and emollient. It is clear, colorless and odorless and is highly volatile, so rather than absorbing into skin it evaporates from it, leaving a lightweight, non-oily feel with good slip and no tackiness. These traits make it valued for improving spreadability and for long-wearing makeup such as mascaras and foundations, as well as in makeup removers; in sunscreens it contributes to a light, fast-spreading texture.
Safety & warnings
Isododecane belongs to the isoparaffin family, which the Cosmetic Ingredient Review Expert Panel has assessed as used in cosmetics. As a volatile, inert hydrocarbon it largely evaporates after application and is generally considered low-irritation and non-sensitizing for most users; its main cosmetic role is sensory, giving a dry, light finish. People who prefer to avoid volatile solvents on very dry or compromised skin may simply note its quick-evaporating nature.
Origin & sourcing
It is a fully synthetic isoparaffin. Commercial isododecane consists almost entirely of permethylated C12 isoparaffins, with 2,2,4,6,6-pentamethylheptane as the main isomer, and it is produced by oligomerization of isobutene followed by hydrogenation, which converts the unsaturated isododecene into the saturated isododecane. The isobutene feedstock can be petroleum-derived or, in newer routes, sourced from bio-based isobutanol.
Questions everyone asks
Does isododecane absorb into the skin?
No. It is highly volatile and evaporates from the skin rather than absorbing, leaving a lightweight, non-oily finish with good slip.
Is isododecane natural or synthetic?
It is fully synthetic, made by oligomerizing isobutene and then hydrogenating it; the isobutene feedstock can be petroleum-based or bio-derived.
Why is it used in sunscreen?
It is a fast-spreading, volatile emollient and solvent that helps the product apply lightly and dry down without a greasy feel.