Ask Dr. Schultz
How much physical sunscreen to apply?
How much physical sunscreen should you put on the face and neck, and how often do you need to reapply?
The reapplication guidelines for both physical (chem-free) and traditional carbon-based sunscreens are the same: reapply after swimming, sweating, or at the very least, every three to four hours if not doing any physical activities.
However, you need less physical sunscreen than traditional sunscreens; use about 1/3 to 1/2 as much because the physical sunscreens are made from very small particles (called “micronized”, which means the particles are made in a very small size) which spread better, give you more coverage and form a thinner layer so you don’t need as much.