Alba Botanical Facial Sheer Shield Sunscreen SPF 45 Versus Dermalogica Oil Free Matte SPF 30

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.

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

Its main roles are:

Glyceryl Stearate Se is a self-emulsifying (SE) form of glyceryl stearate. Self-emusifying means this ingredient automatically blends with water. It is an emulsifier, emollient, and cleansing agent.

As an emulsifier, Glyceryl Stearate Se prevents ingredients such as oil and water from separating. It is also a surfactant, meaning it helps cleanse the skin. Surfactants help gather oil, dirt, and other pollutants so they may be rinsed away easily.

Camellia Sinensis Leaf Extract is derived from the leaves of the tea plant. Black tea, green tea, and oolong tea are all harvested from this plant.

This ingredient has many skin benefits:

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.

Polysorbate 60 is used to help stabilize products. It is a surfactant and emulsifier. These properties help keep ingredients together in a product. Surfactants help reduce surface tension between ingredients with different states, such as liquids and solids. Emulsifiers help prevent oils and waters from separating.

Polysorbate 60 is sorbitol-based and created from the ethoxylation of sorbitan. Ethoxylation is a chemical reaction used to add ethylene oxide. Sorbitan is a the dehydrated version of sorbitol, a sugar found in fruits.

Xanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny.

On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multiple sugar molecules bonded together.

Potassium Sorbate is a preservative used to prevent yeast and mold in products. It is commonly found in both cosmetic and food products.

This ingredient comes from potassium salt derived from sorbic acid. Sorbic acid is a natural antibiotic and effective against fungus.

Sodium Benzoate is a preservative. It's used in both cosmetic and food products to inhibit the growth of mold and bacteria. It is typically produced synthetically.

Both the US FDA and EU Health Committee have approved the use of sodium benzoate. In the US, levels of 0.1% (of the total product) are allowed.