This Serum is a must for any skin care line. It is formulated to be light yet bring a high concentration of vitamin C esters to the skin every day. Vitamin C esters and extracts make this serum luscious. The vitamin C esters absorb readily into the skin and is used at high concentrations in this line without stinging your skin. Vitamin C esters, vitamin E and extracts create a synergetic blend that helps fight off the assault your skin encounters on a daily basis from free radicals. The serum gives your skin a fighting chance against the elements, age and the harm the sun does to your skin on a daily basis. This light formula can be used under or over your makeup. Essential or fragrance oils can be added at .25 – 1%.