What is zinc oxide sunscreen?

Zinc oxide sunscreen uses the mineral compound zinc oxide as an active ingredient. It sits atop of the skin where it absorbs and reflects UV rays, converts them into infrared heat energy, which radiates safely away from the skin. Zinc oxide sunscreens start working immediately and do not seep into the skin like petrochemical products.

Acting alone, zinc oxide is extremely good at protecting against both UVA and UVB rays, surpassing the coverage of all petrochemicals and even titanium dioxide, which lacks coverage in the 2nd half of the UVA spectrum. Zinc oxide is also the only active sunscreen ingredient that’s FDA approved for use on infants.

The only drawback to zinc oxide sunscreens is cosmetic, since zinc oxide usually leaves a white film, especially when applied thickly or not rubbed in completely. However, properly formulated zinc oxide sunscreens can be spread to a thinness that is fully protective while being almost transparent on skin.

 

UV Protection

Zinc oxide is simply THE best active sunscreen ingredient, and by a wide margin. Covering the entire UVA/UVB spectrum by itself, it has the most consistently effective absorption capabilities, which never degrade. In contrast, petrochemical sunscreens need multiple active ingredients for complete coverage, which degrades quickly on the shelf, and even titanium dioxide needs significant help (from zinc oxide) to cover a large portion of the UVA spectrum range.

Zinc oxide is the most effective sun protector available, blocking out both shorter and longer wave UVA rays as well as all UVB rays. In fact, zinc oxide is the only active sunscreen ingredient that covers the entire UVA/UVB spectrum by itself.

 

Chemistry

ZnO occurs naturally in the mineral zincite, but most of the commercial products are made by the high-temperature oxidation of zinc ore, which is melted then vaporized into a gas where it reacts with oxygen to form solid ZnO. Zinc oxide is an inorganic compound and is insoluble in water. It has antimicrobial properties that help wounds heal more quickly, and it is non-comedogenic — i.e. it’s oil-free and won’t clog pores.

Non-nano zinc oxide is highly stable under most conditions, including when hit with UV rays. It absorbs UV energy via bandgap absorption (it reflects and scatters visible light, that’s why it looks white), preventing skin penetration and cell damage. Zinc oxide holds tight to its electrons when it absorbs UV energy, limiting the creation of free radicals that cause oxidative damage or increase the risk of skin cancer.

 

Effect on Humans

Non-irritating and easy on sensitive skin, zinc oxide has been used in skincare for 1000s of years. A skin protectant widely used in treating various forms of skin irritations, it’s used in diaper creams, calamine lotion, and toothpastes. Zinc is a critical mineral nutrient that keeps us healthy. It’s also great for use around the eyes, as it won’t cause stinging.

 

Effect on Reefs

Zinc oxide is a powdered mineral that doesn’t dissolve in seawater, and in its non-nano variety (meaning its particles are all large enough to not seep through skin pores or enter marine biosystems) it rapidly settles to the seafloor and becomes part of the sediment.

Non-nano zinc oxide is safe for reefs and marine life, but NANO zinc oxide particles (smaller than 100 nanometers) can be ingested by marine animals including coral, causing internal damage, and when washed off into the ocean, they can react with UV rays to generate hydrogen peroxide which can be toxic to phytoplankton—a vital nutrient to many reef and coral species.

 

Conclusion

The best sunscreen active ingredient, for both human and marine biosystems, is non-nano zinc oxide. It’s vital to read sunscreen labels (not just the marketing messages) and understand the ingredients used in sunscreen and skincare products. Always check the ingredients, know what those ingredients do, and decide for yourself. And if you have questions, we're just an email away at mac@gowaxhead.com.