If you’re using makeup with a chemical based sunscreen – careful! Some of the pigments can be degrading the chemical sunscreen avobenzone – rendering its protection useless.
Check the back of your sunscreen and make sure it doesn’t contain avobenzone (For North American sunscreens, it’ll be listed under ‘Active Ingredients’). Unfortunately for Americans it’s one of three approved UVA sunscreens – Mexoryl SX and Zinc Oxide are the other two.
An experiment showed avobenzone combined with yellow and black iron oxides lead to a complete degradation of the avobenzone – rendering it useless as a sunscreen. Red iron oxide had no effect on the product.
As well makeup generally contains titanium dioxide as an opacifier, the same experiment showed that uncoated titanium dioxide also degraded avobenzone.
So what does this mean? Look for an avobenzone free sunscreen that has a next-generation UVA sunscreen such as Mexoryl SX or Tinosorb M. You may also consider switching to physical sunscreen with zinc oxide as the UVA absorber.