Caffeine is most associated with coffee, tea, and cacao. In skincare, it helps with calming inflammation and is rich in antioxidants.

While caffeine is used to treat cellulite and and dark circles, further studies are needed to prove this. It has been believed to help with these skin conditions due to its ability to dilate blood vessels and increase blood flow.

Pentylene glycol is typically used within a product to thicken it. It also adds a smooth, soft, and moisturizing feel to the product. It is naturally found in plants such as sugar beets.

The hydrophilic trait of Pentylene Glycol makes it a humectant. As a humectant, Pentylene Glycol helps draw moisture from the air to your skin. This can help keep your skin hydrated.

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.