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.

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.

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.

Madecassic Acid is a major component of Centella Asiatica Extract. It has anti-inflammatory and antioxidant properties.

It is a triterpenoid, meaning it naturally acts as an antioxidant. Antioxidants protect your skin against damage from environmental factors such as pollution and UV.

Madecassoside comes from the super popular skin-soothing ingredient, Centella asiatica. It is one of four active compounds found in the extract of Centella Asiatica.

Madecassoside has antioxidant, anti-inflammatory, and hydrating properties. It contains fatty acids, amino acids, beta-carotene, and phytochemicals.

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

It’s often used to:

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.