Medik8 Crystal Retinal 1 is perfect if you have sensitive skin or if you are new to retinol. This serum contains 0.01% encapsulated retinaldehyde (a form of retinol/vitamin A). Retinol must first be converted to retinaldehyde and then to retinoic acid before the skin can use it. By using encapsulated retinaldehyde, the ingredient only needs to be converted once, making it work up to 11 times faster than standard forms of retinol. The crystalline capsule containing retinaldehyde is broken down by the skin's natural enzymes when applied to the skin. This ensures maximum stability and absorption. The active ingredient is also released gradually during the night, for minimal risk of irritation. Retinaldehyde tackles fine lines, wrinkles, pigment spots and an uneven skin texture. It also works antibacterially and it fights acne-causing bacteria, for a clear skin. Hyaluronic acid attracts water from the atmosphere and holds it in the skin, so that the skin feels supple and nourished. Vitamin E has an antioxidant effect, it eliminates free radicals and stabilizes retinaldehyde for optimal functioning. Glycerine retains water in the skin and ensures a comfortable and hydrated skin.