function of ingredients

water

helping spread the product and mix other ingredients in the solution. It also replenishes moisture into the skin, which is vital considering water makes up the majority of our skin cells.

emollients

aid in the spreadability of the product and also helps to keep the product in place. It lubricates the skin and fills in the gaps to provide a smooth skin appearance.

surfactants

function to reduce surface tension between the skin’s surface and the product, allowing for better cosmetic performance. Surfactants come as (1) Detergents which lift dirt and oil off the skin and (2) Emulsifiers which keep water and oil blended in a product, preventing the customer from needing to vigorously shake it repeatedly.

thickeners

give consistency to gel-like products, allowing for easier spreadability and a more consistent feel.

fragrance

used in cosmetics primarily for their sensory effects rather than their functionality. Fragrances are not necessary for the effectiveness of a product and are the most common causes of allergic reactions.

preservatives

keep bacteria out of products and stop chemical changes from occurring that hinder the effectiveness of the cosmetic.

humectants

draw water to the skins surface, helping to ensure healthy skin hydration. Most moisturizers are a combination of humectants and emollients.


source: http://factoidz.com/the-function-and-use-of-cosmetic-ingredients/