Ultra-strength Retinaldehyde - 11 x more efficiently delivered than retinol with a direct action on bacteria Apply twice a week for 2 weeks , then every other night for 2 weeks, then every night. Start on low doses and build up. Youth Vitamin stimulates collagen and elastin. KEY INGREDIENTS Encapsulated Retinaldehyde, Patent-Pending Stabilisation System, Hyaluronic Acid, ​Vitamin E & Glycerin