Vitamin C is an effective antioxidant, brightens the skin tone and reduces signs of ageing. In its pure form, Vitamin C is unstable in water. Ascorbyl Glucoside is a water-soluble derivative of Vitamin C. It is much more stable in water but it is less potent than direct L-Ascorbic Acid.
Being more compatible with water allows for a very pleasant serum texture. It is considered a gold standard of Vitamin C derivatives due to its high stability and comfortable use, but it's impossible to achieve extremely high L-Ascorbic Acid potency with this solution. Aside from the general benefits of pure Vitamin C, Ascorbyl Glucoside has been shown to offer specific skin brightening benefits.