Chemical filter sunscreens products typically include a combination of two to six of the following active ingredients: oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate. Many of these sunscreens are ineffective and studies have shown in addition to hormone disruption, skin penetration, skin allergies, cell damage and other concerns.
Chemical sunscreens absorb UV radiation. This means UVA rays, the type responsible for more serious damage, reach deeper layers of skin. Most chemical UV filters protect from UVA or UVB rays, not both.
Sunscreens that use mineral filters as the primary active are called physical, inorganic or mineral sunscreens. The active mineral ingredients in sunscreens are zinc oxide and/or titanium dioxide. Zinc oxide is a naturally occurring mineral that is formed from the metal zinc and titanium dioxide is also a naturally occurring mineral that is formed from the metal titanium.
These mineral filters create a physical barrier on the top of the skin. The mineral filter sunscreen molecules reflect and scatter both UVA and UVB rays from the skin. That's why mineral sunscreens are effective on application. Unlike chemical sunscreens, the mineral filters do not break down and release heat into the skin.
Both zinc oxide (ZnO) and titanium dioxide (TiO2) are safe and very stable in formula and when exposed to the sun. They are not absorbed by the skin and therefore do not cause allergic reactions. Chemical sunscreens tend to cause more allergic reactions.
Many sunscreen manufactures utilize zinc oxide nanoparticles (less than 35 nanometers in diameter), often referred to as clear zinc sunscreen. Nano zinc oxide particles are very harmful for marine organisms, which induces a severe and fast coral bleaching due to the alteration of the symbiosis between coral and zooxanthellae.
Non-nano zinc oxide and non-nano titanium dioxide are the only coral-safe sunscreen filters and they are safe and effective in blocking UV rays. Sunscreens formulated with non-nano particles will clearly state "non-nano zinc oxide and/or non-nano titanium dioxide on the products active ingredient list".