Medik8 Crystal Retinal 1 is a stable night serum for gentle-strength vitamin A. This next-generation serum visibly smooths wrinkles, brightens dark spots, and firms skin. Containing retinaldehyde, a potent form of vitamin A, it works faster than retinol without irritation. Its patented retinal stability system ensures potency until the last drop. Hyaluronic acid and glycerin moisturize and hydrate minimizing any dryness.