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.

Caprylyl Glycol is a humectant and emollient, meaning it attracts and preserves moisture.

It is a common ingredient in many products, especially those designed to hydrate skin. The primary benefits are retaining moisture, skin softening, and promoting a healthy skin barrier.

Centella Asiatica Extract (Centella) is derived from an herb native to Southeast Asia. It is famous for its anti-inflammatory and soothing properties.

Centella is rich in antioxidants and amino acids, such as Madecassic Acid and Asiaticoside.

Ceratonia Siliqua Gum is extracted from the seeds of the carob tree. You might know this ingredient as Carob Gum or Locust Bean Gum. It is used to stabilize other ingredients and improve the texture of products.

Carob gum is made up of long-chain polysaccharides. This makes it a natural thickener.

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.

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.