Reveal younger-looking skin with just one tube of Crystal Retinal serum. Medik8's Vitamin A night serum is clinically proven to visibly smooth stubborn wrinkles, brighten dark spots, reduce blemishes, and firm the skin – without irritation. Crystal Retinal contains retinaldehyde, a next-generation vitamin A that works 11 times faster than standard retinol, and unlike others, Medik8's patented retinaldehyde stability system ensures its unparalleled potency and efficacy until the very last drop.