Menthol is a compound found in mint plants, such as peppermint. In its pure form, it is a clear crystalline substance.

Menthol is known for its cooling sensation; however, the cooling is actually from your skin being sensitized. Menthol can worsen rosacea. We recommend speaking with a professional if you have concerns.

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.