Phosphatidylcholine is a type of phospholipid that can be obtained from sources such as egg yolks and soybeans. It is a unique phospholipid because of its structure: it has a choline head attached to a chain of essential fatty acids that make up the tail. These structural components allow phosphatidylcholine to manufacture and repair cell membranes throughout the body, including within the skin.

Phosphatidylcholine is used in skin care products because it enhances the penetration of other ingredients and absorbs well without feeling greasy or heavy. Once absorbed, phosphatidylcholine functions as an excellent water-binding agent that can help maintain skin hydration. Phosphatidylcholine also supplies the skin with the beneficial components choline and linoleic acid.

In addition to functioning as an active ingredient in skin care products, phosphatidylcholine can be used as an emulsifier in formulations that contain both water and oil components. Mixing water and oil together creates a dispersion of oil droplets in water (and vice versa). However, these two phases can separate if the product is left to settle. To address this problem, an emulsifier can be added to the system to help the droplets remain dispersed.