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.

This ingredient is also known as PMMA. It is a polymer microsphere, composed of tiny, perfectly spherical particles formed from repeating units.

In cosmetics, PMMA is mainly used to give a soft or blurring effect. The transparent particles are able to scatter light and help reduce the appearance of fine-lines and imperfections.

Sodium Hyaluronate is hyaluronic acid's salt form. It is commonly derived from the sodium salt of hyaluronic acid.

Like hyaluronic acid, it is great at holding water and acts as a humectant. This makes it a great skin hydrating ingredient.

Tocopheryl Acetate is AKA Vitamin E. It is an antioxidant and protects your skin from free radicals. Free radicals damage the skin by breaking down collagen.

One study found using Tocopheryl Acetate with Vitamin C decreased the number of sunburned cells.

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.