Cetaphil
Gentle Skin Cleanser
Sensitive to the needs of dry skin, this fragrance- and soap-free facial cleanser won't dry your skin, won't dull your healthy glow.
Ingredients overview
Water,
Cetyl Alcohol,
Propylene Glycol,
Sodium Lauryl Sulfate,
Stearyl Alcohol,
Methylparaben,
Propylparaben,
Butylparaben
Emollient: Cetyl Alcohol, Stearyl Alcohol
Emulsifying: Cetyl Alcohol, Sodium Lauryl Sulfate, Stearyl Alcohol
Moisturizer/humectant: Propylene Glycol
Perfuming: Propylparaben
Preservative: Methylparaben, Propylparaben, Butylparaben
Solvent: Water, Propylene Glycol
Surfactant/cleansing: Cetyl Alcohol, Sodium Lauryl Sulfate, Stearyl Alcohol
Viscosity controlling: Cetyl Alcohol, Propylene Glycol, Stearyl Alcohol
Water
Good old water, aka H2O. The most common skincare ingredient of all. You can usually find it right in the very first spot of the ingredient list, meaning it’s the biggest thing out of all the stuff that makes up the product.

It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water.
Cetyl Alcohol
A so-called fatty (the good, non-drying kind of) alcohol that does all kinds of things in a skincare product: it makes your skin feel smooth and nice (emollient), helps to thicken up products and also helps water and oil to blend (emulsifier). Can be derived from coconut or palm kernel oil.
Propylene Glycol
It's a helper ingredient that improves the freeze-thaw stability of products
It's also a solvent, humectant and to some extent a penetration enhancer
It has a bad reputation among natural cosmetics advocates but cosmetic scientists and toxicology experts do not agree (read more in the geeky details section)
Sodium Lauryl Sulfate
The famous or rather infamous SLS (not to be confused with SLES). It is a cleansing agent known for being too good at the job and potentially irritating the skin. But, on the positive side, it can produce copious, creamy and luxurious foam compared to the more gentle and thus nowadays much more commonly used Sodium Laureth Sulfate.

In fact, SLS is so good at irritating the skin that it is very commonly used in dermatological studies just for that. It is a so-called "primary irritant", a substance that irritates the skin in one go (without prior sensitization) but doesn't do any other big harm (such as being carcinogenic or systematically toxic - those claims are not true). Also, the formula can greatly influence the irritating potential of SLS, and mixing it with other cleaning agents makes it milder.
Stearyl Alcohol
A handy multi-tasker, white to light yellowish oil-loving wax that works very well in oil-in-water emulsions. It makes your skin feel nice and smooth (emollient), stabilizes oil-water mixes and gives body to them.

Oh, and one more thing: it's a so-called fatty alcohol - the good, emollient type of alcohol that is non-drying and non-irritating. It is often mixed with fellow fatty alcohol, Cetyl Alcohol, and the mixture is called Cetearyl