Here’s a breakdown on how the chemical sunscreen and physical block sunscreen differ in the way they protect the skin from the sun.
Chemical sunscreens take 30 minutes to actually penetrate in the skin cells and they absorb the UV rays and reflect the rays by causing a chemical reaction within. However, this can be very irritating to the skin and may cause hormone disruption. They can also create cell-damaging free radicals when exposed to the sun. The higher number SPF you apply with a chemical reaction the more irritating is on the skin. It is not recommended or necessary to go higher than SPF 50. The higher the number doesn’t protect you any more, just more irritating.
Physical block sunscreen, when applied is like laying thousands of little mirrors over the skin and reflects the UVA and UVB rays away. This is much healthier for the integrity of the skin. There are only 2 physical sunscreens, titanium dioxide and zinc oxide. Both are minerals and are nonirritating, nonallergenic, and non-comedongeic. They won’t clog the pores or aggravate acne. Zinc oxide and titanium oxide can actually be very healing and soothing on the skin. To make sure you are getting the full number of the SPF you need to apply a nickel to quarter size to each area; face, neck, and chest. Most people do not put on an adequate amount. This is key. For the rest of body it’s about 2 oz. or a shot glass worth.
My advice: For everyday wear I absolutely recommend a physical block of at least SPF 15-30, that number depends on your day to day activities. This is the ideal sunblock because it is safe, non-clogging, healing, and protective. I would not recommend using a chemical sunscreen everyday as it can cause breakouts, inflammation, and can be very damaging.
I keep Rhonda Allison’s Ezinc Spf 18 in my bag. When I am driving I will pull it out and put some on the tops of my hands. Since it is a physical block, I am being protected right away. Don’t forget about your hands! Face, neck, chest, and hands see the sun every single day rain or shine. Protect them!
However, if you are out at the beach, going hiking, running, etc. where you have longer exposure to sun, I would absolutely recommend wearing your SPF30-50 physical block to start and reapply every hour. If all you have is a chemical SPF spray or lotion to reapply, then use it. The sun is still more damaging and carcinogenic than a chemical SPF. Always always protect your skin!
I love Rhonda Allison’s Broad Spectrum Daytime Defense SPF 30. It doesn’t leave that chalky white finish. It’s a natural ultra refined sunscreen. The higher the number of the SPF the thicker it will feel when it goes on. However, this one is so mattifying. I use it on all my clients at the end of their facial.