The MD Formula Hydrating Serum is a lightweight serum designed to give the skin a deep hydrating effect. This advanced professional serum contains a powerful cocktail of 2 key ingredients Polyglutamic Acid at 1% and Vitamin C at 3% Polyglutamic Acid is significantly more hydrating than Hyaluronic Acid. In this formula we are using Polyglutamic Acid with the aim of giving your skin the appearance of deep moisturisation. That healthy look. Vitamin C in this formulation is used with the aim of giving the temporary appearance of a brighter complexion, and for its collagen building characteristics. In some cases Vitamin C has led to a decrease in the temporary appearance of hyperpigmentation.