Medik8 Crystal Retinal 6 Serum visibly transforms skin while you sleep. This stable retinal night serum, with 0.06% retinaldehyde, targets signs of aging by improving the appearance of wrinkles, texture, and tone. A double-layered stabilization system ensures gradual release of this super-strength Vitamin A. Hyaluronic acid and glycerin hydrate, helping to firm skin and brighten dark spots, leaving a smooth, supple complexion.