COSRX Vitamin E Vitalizing Sunscreen SPF 50+ - EU Versus Sk-II Atmosphere Airy Light UV Emulsion SPF 30 PA+++

Cetyl Alcohol is a fatty alcohol. Fatty Alcohols are most often used as an emollient or to thicken a product.

Its main roles are:

Disodium EDTA plays a role in making products more stable by aiding other preservatives.

It is a chelating agent, meaning it neutralizes metal ions that may be found in a product.

Homosalate is a chemical sunscreen filter that provides protection in the UV-B range (280nm - 320 nm), with a peak protection at 306 nm. It is internationally approved for use in sunscreens.

Homosalate is not photo-stable, meaning it's strength as a UV filter degrades over time with exposure to the sun. Because of this, it's often used in combination with other chemical sunscreen filters as avobenzone (which protects from the UV-A range). Homosalate also helps act as a solvent for harder-to-dissolve UV filters.

Octocrylene protects skin from sun damage. It absorbs UV-B with peak absorption of 304 nm. It is a common sunscreen ingredient and often paired with avobenzone, a UVA filter. This is because octocrylene stabilizes other sunscreen ingredients by protecting them from degradation when exposed to sunlight. Octocrylene is a photostable ingredient and loses about 10% of SPF in 95 minutes.

Octocrylene also acts as an emollient, meaning it helps skin retain moisture and softens skin. It is oil-soluble and hydrophobic, enhancing water-resistant properties in a product.

Panthenol is a common ingredient that helps hydrate and soothe the skin. It is found naturally in our skin and hair.

There are two forms of panthenol: D and L.

Peg-100 Stearate is an emollient and emulsifier. As an emollient, it helps keep skin soft by trapping moisture in. On the other hand, emulsifiers help prevent oil and water from separating in a product.

PEGS are a hydrophilic polyether compound . There are 100 ethylene oxide monomers in Peg-100 Stearate. Peg-100 Stearate is polyethylene glycol ester of stearic acid.

Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.

So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.