Dihydroxyacetone, or DHA, is a simple sugar. It is frequently used in self-tanning products.

DHA binds to the amino acids in your dead skin cells to create a brown/orange color. Darkening begins to kick in a few hours after application and will continue to develop for up to 3 days. This ingredient can be drying.

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.

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.