Butylene Glycol (or BG) is used within cosmetic products for a few different reasons:

Overall, Butylene Glycol is a safe and well-rounded ingredient that works well with other ingredients.

Disodium EDTA plays a role in making products more stable by aiding other preservatives.

It is a chelating agent, meaning it neutralizes metal ions that may be found in a product.

Ethylhexylglycerin (we can't pronounce this either) is commonly used as a preservative and skin softener. It is derived from glyceryl.

You might see Ethylhexylglycerin often paired with other preservatives such as phenoxyethanol. Ethylhexylglycerin has been found to increase the effectiveness of these other preservatives.

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.

Hydrogenated Lecithin is created from the hydrogenation of lecithin (a group of phospholipids). Hydrogenation is a chemical reaction between hydrogen and another element.

This ingredient is an emollient and emulsifier. As an emollient, it helps soften skin by trapping moisture within. As an emulsifier, it prevents oil and water ingredients from separating.

Propanediol is an all-star ingredient. It softens, hydrates, and smooths the skin. 

It’s often used to:

Rosmarinus Officinalis Leaf Oil is oil expressed from the leaves of the rosemary plant.

Rosemary Leaf Oil is a fragrance and helps give your product a scent. If you are sensitive to irritating fragrances, this one contains camphor. Camphor has been found to irritate skin.

Sodium Polyacryloyldimethyl Taurate is a polymer and used to help stabilize other ingredients.

Emulsion stabilizers hold ingredients together, helping to create an even texture throughout the product.

Soluble collagen comes from animals and fish. It has a large molecule size, meaning it doesn't get absorbed into skin.

Instead, it sits on top of skin as a humectant to improve skin hydration. It has incredible water-binding properties and creates a water barrier on skin that prevents evaporation.

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.