was that 2 questions or the same one? anyway i know it stopped working for me quite quickly, infact im not 100% sure it ever really started, i was very sensitive to it and spent alot of time in the sun whihc made me very red. i imagine you will become immune to it after a few months, i wouldnt advise using it longer than that anyway. things like bp all say not to use them continuously for more than 3 months, i imagine that will go for retin-a too.
Has it stopped working for you then or are you just starting it or just curious or what?
I used retin-a for a couple years, and it worked great and then my skin got immune to it and it didn't work any longer...my problem with retin-a is that how it works is by thinning and turning your skin over so to speak which is why they recommend that you don't have over exposure to the sun, but while I was using it, it caused my face to burn everytime I washed my face and I didn't like that so I stopped using the retin-a because of that reason, because I was getting to point of washing my face, but dreading it because of how painful it was going to be
I've been using it for about 4 years, and my zits have never completely gone away. Strangely, my supply of retin-a ran out about a month ago, and my skin seems to be improving since not using it.....hmmmmmmmmmm.........