Perricone MD Essential Fx Acyl-Glutathione Intensive Overnight Moisturizer is a facial serum that is designed to intensely nourish the skin overnight. It contains Acyl-Glutathione, a powerful antioxidant that helps protect the skin from harmful environmental factors and minimizes the signs of aging. It is suitable for all skin types. Here are some insights from user and expert reviews: Pros Improves skin texture Feels nice on skin Leaves face soft and moisturized