Water is a great solvent. It’s neutral and doesn’t provide any strong positive or negative effects. It just helps components to mix better and to transport active components.
Sodium PCA is a nice moisturizer and skin softener. It contains amino acids and Sodium Hyaluronate. It’s part of the Natural Moisturizing Factor (NMF) that is responsible for keeping the outer layer of the skin hydrated. If you don’t have enough NMF you can face dryness even if you don’t have other skin problems.
Glycerin is one of the most outstanding and helpful skincare components. It's used in many skincare products because it works and provides notable results. It's one of the best moisturizers. Molecules of Glycerin can absorb water and deliver it into deep layers of the skin making it hydrated.
Potassium Sorbate is a preservative that increases the shelf life of the product. It’s a great alternative to parabens. That's why manufacturers like to use this component. It is safe in concentration of up to 10% but it is used in cosmetics in amounts of 1% or even lower.