Why can some sunscreens leave white marks?

Some sunscreens can occasionally leave marks and tend to leave white traces after application, which can then dull the complexion. These traces primarily come from the percentage of mineral sun filters present in the formulation, either titanium dioxide or iron oxide, although they provide optimal coverage of the UV spectrum.

They present themselves in the form of white mineral powder that remains on the skin's surface to reflect UV rays, hence the traces. Titanium dioxide leaves more white traces due to the large size of its particles.

Furthermore, the higher the SPF, the more the formula will be enriched with sun filters, and the more the cream will leave white marks on the skin. However, even if they are unsightly, these marks can be an excellent indicator of the proper application of the sunscreen.

Can we prevent these white marks on the skin?

This whitening effect can be minimized. The idea is to take the time to spread your sunscreen well. Additionally, nowadays, new galenic/textural developments help reduce this effect by facilitating their application. The result: the easier the sunscreen is to apply, the better it will spread and the fewer white marks there will be.