I hope this doesn’t sound like a lecture… I have been a rabid sunscreen wearer since I was 15.
I’m 51 now and I know it’s paid off when I compare my skin to that of my friends. (Not a stealth boast, I promise. I used to work with a lot of stunning East Asian women who looked decades younger than their age and picked up a lot of skincare tips from them, but was still dubious about experimenting with their sunscreens until I had spoken to my dermatologist.) Anyhow, this is the simplest (but long) explanation about the differences in sunscreens and how they work.
Physical sunscreens contain minerals like zinc and/or titanium dioxide. They create a barrier that blocks the UV radiation. They have been considered Gold Standard In Western countries, but there is no consensus about how much it protects you from UVA. Scientists agree that it “mitigates” UVA damage. (Cheat sheet:- B Is for Burning and A is for Aging.) This is why over here some are referred to as “Broad Spectrum” as they know it helps, but can’t prove how exactly how much. (I believe in the UK they have a star system, but I don’t know enough about that.)
Chemical sunscreens absorb UV radiation into the skin and convert it into heat. If you look at Korean & Japanese sunscreens, (not pushing you, but these are the ones I know about because I have been using them for donkey’s years…) Heat is also considered to be a damaging form of radiation (esp for aging and inflammation. UVA is blamed for melasma and hyperpigmentation) so they contain cooking, soothing ingredients (usually plant extracts like Cica (Centella Asiatica) and Mugwort, etc.)
There are many, many hybrid sunscreens as well. Absolutely the best of both worlds. They feel better than physical sunscreens and they offer all of the protection of both. (Chemical and hybrid sunscreens both tend to play nice with makeup .too.)
Korean Sunscreens have a different spf rating. The number equates to the same thing 30 = 30 times the usual time to burn, 50 = 50x, etc. Their ratings also include the “Plus” which refers to the UVA protection.
- PA + equals a 2–4 UVA-PF (50–75% protection against UVA rays)
- PA ++ equals a 4–8 UVA-PF (75–88% protection against UVA rays)
- PA +++ equals a 8–16 UVA-PF (88– 94% protection against UVA rays)
- PA ++++ equals a 16 or more UVA-PF (94% or higher protection against UVA rays)
(I cut and pasted that bit.)
I use chemical sunscreens every single day. If I am going to the beach (rare, due to genetic issues and hatred of hot, crowded places… oh, and sand. Blech!) I use a hybrid one. Most hybrid ones don’t leave behind a white cast like physical sunscreens, but are still have a little less of a “skincare” feel than the chemical ones due to the slightly more viscous consistency. They’re light years away from physical ones though.
Phew! Sorry that was so long! Hope that helps!