I previously have been using "The Ordinary" for Retinol, but started transitioning to Q&A recently and was a bit worried about starting to use the Retinol serum. However, it is great. Easy to use, no bad reactions at all (and I have sensitive skin) and so far I definitely can see that my skin has maintained what I'd expect using a Retinol. As I love all the products so much, I am officially transitioned to a full Q&A product customer.