Glycerin is already naturally found in your skin. It helps moisturize and protect your skin.

A study from 2016 found glycerin to be more effective as a humectant than AHAs and hyaluronic acid.

This ingredient is a semi-synthetic polymer created from cellulose. In case you need a refresher, cellulose is the main component of plant cell walls.

Hydroxypropyl Methylcellulose has many uses:

• emulsifier
• create a gel-like texture
• boost foam

Kaolin is a clay. It is used for oil control and to help minimize pores. Like other clays, kaolin has the ability to absorb excess sebum or oil. This can help clean out pores and mattify the skin.

Some types of kaolin may have exfoliating properties. When water is added to kaolin, it becomes a paste with small abrasive particles.

Mannitol is a sugar alcohol. It is a humectant and moisturizes the skin. In vitro (not tested on a living organism), mannitol displays antioxidant properties.

When found in aqueous solutions, mannitol tends to become acidic. This is because it loses a hydrogen ion. This is why mannitol can often be found with pH adjusting ingredients, such as sodium bicarbonate.

Microcrystalline Cellulose is another name for refined wood pulp. It is used as an emulsifier and mattifying ingredient. As an emulsifier, it helps keep ingredients together.

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.

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.