Do titanium dioxide and zinc oxide make the best sunscreens?
Titanium dioxide and zinc oxide are physical sunscreens and work by reflecting and scattering light. To provide enough protection on their own, the high concentrations make the product white and opaque on the skin, which most people find unacceptable. Micronized titanium dioxide or zinc oxide (e.g. Z-Cote) are less opaque but they have less protection against the longer UVA wavelengths. Part 2: How to use sunscreens correctly How much sunscreen should be applied? 2 mg per cm2 should be used V this is the thickness for SPF testing. This translates into using 1 to 1.5 ml (about ½ teaspoon) for the face and 35 ml for the whole body. Be sure to cover all exposed areas evenly. The protective effect of sunscreen drops drastically when applied too thinly. At 1 mg per cm2 (which is the common thickness), one may get less than 20% of the stated protection. How often should sunscreens be applied? If you are exposed to sunlight, sunscreens should be reapplied frequently V every 30 minutes to two
