Crystal Retinal 1.

"Retinoids are notoriously irritating to the skin and can cause a lot of dryness and peeling with quite a long acclimation period somewhere between weeks and several months. The Medik8 Crystal Retinal 1 is exceptional because I find that you can acclimate to it quite quickly but it's also very very effective. It is a retinal derivative product, so that's a step up in potency and efficacy from retinol, but it's level one and this goes all the way up to level 20. I really like that Medik8 creates their retinoids in gradients so you can start with something less potent if you have sensitive skin or you're a beginner and then work your way up as you tolerate it. Retinal is traditionally tricky to formulate with, hard to keep stable and effective, but Medik8 has a great technology approach to this and their products with retinal are wonderful. It's nice and creamy and you just need a really thin layer, one pump for your entire face. I really like this because you can use it on your neck. A lot of people can't use prescription retinoids on their neck because it's too irritating, but this one's fantastic. Once someone with sensitive skin is able to tolerate this every single night on their skin without issues, then they could go up to the next strength."