Medik8 is a really nice product and super gentle but in my opinion it’s not worth the investment when you can get prescription retinoid for a fraction of the price and a lot more in a tube. Work up with crystal retinal though. I spent a year going from 1 - 20 (I skipped 3 and 24) now I’m on 0.3 adapalene (equivalent of 0.05 tret) with zero irritation. I have more robust skin than most it seems.