What it is
Menthoxypropanediol is a menthol-derived diol that delivers a cooling, refreshing sensation on the skin without the strong aroma or sharp sting of free menthol. Because it is essentially non-volatile, the cool feel develops gradually and persists longer than that of menthol itself, which makes it useful in summer and after-sun formulas. In sunscreens it is added mainly for a pleasant cooling skin-feel rather than for any protective function.
Safety & warnings
Menthoxypropanediol is generally well tolerated at the low levels used in cosmetics and is milder than free menthol, producing cooling with little of menthol's pungency. As a menthol-type cooling agent it can still cause a tingling or stinging sensation on compromised or sensitive skin, and concentration is kept low to avoid irritation. It is not a recognized fragrance allergen of the type that must be label-declared.
Origin & sourcing
Synthetic; made by reacting menthol with a glycidol or propanediol building block to attach a 1,2-diol group, giving a water-compatible cooling molecule.
Questions everyone asks
Why is menthoxypropanediol added to sunscreen?
It provides a cooling, refreshing skin sensation that makes a product feel pleasant in hot weather, without contributing to sun protection itself.
How is it different from menthol?
It is derived from menthol but is largely non-volatile, so it gives a milder, longer-lasting cool feel with much less of menthol's strong smell and sting.