Chemical/Physical Sunscreen — Chemical sunscreens ( like Parsol) absorb UV rays before they can damage skin cells. Physical sunscreens such as zinc oxide stay on the skin’s surface and reflect UV radiation away from the body. But wait, there’s more.
Most chemical sunscreens such as Homosalate and methoxycinnamate ( that trips lightly off the tongue) protect against UVB rays. However there are a two chemcial sunscreens Parsol( Avobenzone) and Mexoryl which protect against UV A rays. This is why most sunscreens have so many active ingredients– no one ingredient can do it all.
Physical sunblocks are made of minerals such as zinc ocide and titanium dioxide that can block both UV A and UVB rays. However, how well they work depends on the formulation. The thick, white zinc oxide paste is highly effective, but certainly not something you can use all over the body. Micronized forms of these mineral sunscreens look fine but need to be combined with chemcial sunscreens for optimum protection.
Bottom line here: to get the protection you want look for a broad-spectrum sunscreen with a list of 3-4 active ingredients. Do that and you’ll be protected without needing a degreee in bio chem to make the right choice.