Estée Lauder Double Wear Stay-in-Place Flawless Wear Concealer Versus Rimmel London Lasting Matte Concealer

Cyclopentasiloxane (D5) is a lightweight silicone that mostly acts as an emollient and solvent in cosmetics. Its the reason your products feel silky, fast-spreading, and non-greasy.

Since D5 is volatile, it does its thing and then evaporates off the skin quickly.

Laureth-7 is created by the ethoxylation of lauryl alcohol using ethylene oxide. Lauryl alcohol is a fatty alcohol with hydrating properties.

This ingredient is an emulsifier and cleansing ingredient. As an emulsifier, it is used to prevent ingredients from separating. It also helps cleanse the skin by gathering dirt, oil, and pollutants to be rinsed away.

Magnesium Sulfate is a salt. More specifically, it is an epsom salt, or the bath salt used to help relieve muscle aches.

Despite having ‘sulfate’ in the name, it isn’t a surfactant or cleansing agent like sodium lauryl sulfate. Unlike those sulfates, magnesium sulfate doesn’t have the same cleansing or foaming properties (it's simply a type of salt).

Pentaerythrityl Tetra-Di-T-Butyl Hydroxyhydrocinnamate (long name, huh?) is a synthetic antioxidant.

It is used to help stabilize other antioxidants or prevent the color from changing in a product.

Phenoxyethanol is a preservative that has germicide, antimicrobial, and aromatic properties. Studies show that phenoxyethanol can prevent microbial growth. By itself, it has a scent that is similar to that of a rose.

It's often used in formulations along with Caprylyl Glycol to preserve the shelf life of products.

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.

Tribehenin is the triglyceride of glycerin and behenic acid. It is an emollient that helps soften and condition skin.

Safety-wise, this is a well-vetted ingredient. Repeated-insult patch tests of 0.38% tribehenin did not trigger sensitization.

This silicone is an emollient. Emollients create a thin film on the skin to prevent moisture from escaping.

It is not soluble in water and helps increase water-resistance in products.

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.

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.