Reveal visibly firmer, brighter-looking skin with just 1 tube of Crystal Retinal. Medik8's bestselling vitamin A night serum is formulated with next-generation retinaldehyde (retinal) which is clinically proven to act 11x faster than retinol* for a visibly brighter, smoother and firmer-looking complexion. Unlike other retinal serums available, Crystal Retinal features Medik8's unique patented stability system to ensure maximum retinal potency, while their industry-leading encapsulation technology delivers powerful yet gentle results with minimal irritation, even on sensitive skin types. Loved and recommended by dermatologists and professionals all over the world, Crystal Retinal features a unique ladder of 5 progressive strengths (0.01%-0.2% retinal) so that you can continue to experience increased visible youth-renewing results. If you're a vitamin A beginner, Medik8 recommends that most people start on Crystal Retinal 3 (0.03%), or Crystal Retinal 1 if you have very sensitive skin (0