Vitamin C serums are specialists designed to deliver a high concentration of vitamin C. Although the formula is oil-and-water-based, it is created to have an oil-free texture. In fact, serums are described as having a velvety finish. Although the formulas do not leave an oily finish, the intensive formula can irritate sensitive skin. People with sensitive skin should look for vitamin C serums. HOW TO USE: Take 3 drop of serum or as required dot in on the face and massage gently in an upward circular motion till the serum is completely absorbed. Use as Day Serum, Night Serum & Before Makeup.