As an absorbent, alumina can give a mattifying effect. It is used in mineral sunscreens to help coat nano-sized filters, such as titanium dioxide. By increasing the size of the UV filters, these ingredients stay on the skin for a longer time. By coating small sized ingredients, alumina helps thicken a product.

Alumina may be used as an abrasive, or exfoliant.

Alumina is naturally occurring in the mineral corundum. Certain varieties of corundum create rubies and sapphires. Corundum is also the crystalline form of alumina.

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Cyclopentasiloxane

Emollient, Skin Conditioning, Solvent

Cyclopentasiloxane, or D5, is a silicone used to improve texture of products and trap moisture.

D5 is considered lightweight and volatile. Volatile means it evaporates quickly after application. Once evaporated, D5 leaves a thin barrier that helps keep skin hydrated.

It is also an emollient. Emollients help soften the skin and prevent water loss. Silicones create a silky texture in products. D5 helps other ingredients become more spreadable.

Studies show D5 is safe to use in skincare products. We recommend speaking with a skincare professional if you have concerns.

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PEG-10 Dimethicone

Skin Conditioning

Peg-10 Dimethicone is silicone with conditioner and emulsifier properties. It mostly acts as an emollient in skincare and and humectant in haircare.

According to the manufacturer, acidic formulations decrease the stability of this ingredient. It works best in neutral or near neutral formulations.

Titanium Dioxide

Cosmetic Colorant, UV Absorber, UV Filter

Titanium Dioxide is a mineral (or physical) sunscreen ingredient that provides broad-spectrum protection by blocking both UV-A and UV-B rays.

It sits on the skin’s surface and primarily reflects and scatters UV light and also absorbs some of it.

This makes the line between “mineral” and “chemical” sunscreens a bit blurry, but in skincare labeling, Titanium Dioxide and Zinc Oxide are the two ingredients officially classified as mineral filters.

Because it’s non-irritating, Titanium Dioxide is often recommended for sensitive or acne-prone skin.

Thanks to modern production methods, nano-scale or fine-grade Titanium Dioxide is now widely used in cosmetics to reduce white cast and improve texture.

Despite its small particle size, studies show that Titanium Dioxide, even in nanoparticle form, is not absorbed into the skin.

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Zinc Oxide

Cosmetic Colorant, Skin Protecting, UV Absorber

Zinc Oxide is a mineral broad-spectrum UV filter; it is the broadest UVA and UVB reflector approved by the FDA. While it is most commonly man-made for cosmetics, it can naturally occur in zincite, a rare mineral.

Today, traditional and nano-sized zinc oxide can be found in beauty products. Nano-sized zinc oxide can enhance a product's UV protection. While it is not believed to have a negative effect on skin, nano-zinc oxide may be harmful to coral reefs - though the verdict is not entirely out on this one.

Zinc Oxide also has antibacterial and calming properties. It is not water soluble.

Zinc has been used throughout history as an ingredient in paint and medicine. An Indian text from 500BC is believed to list zinc oxide as a salve for open wound. The Ancient Greek physician Dioscorides has also mentioned the use of zinc as an ointment in 1AD.

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