Isis Unitone 4 White Advanced Serum 15 mL Isisun4 Ad for dark spotsIsis Unitone 4 White Advanced Serum 15 mL Isisun4 Ad for dark spots A night serum helps to reduce dark spots, it contains a depigmenting agent that helps to limit the overproduction of the skin pigment. It contains kojic acid antimicrobial properties, it helps to lighten skin sun damage and age spots. Ascorbic acid has an anti oxidant that protects skin from free radical damage and it helps to unify skin tone.