@katyjade all the professionals recommend not using actives for 5 days but lots of people on you tube and in this group have been either MN with tretinoin or applying it straight after. They have said they get great results, a much better peel. It will depend on how sensitive your skin is. I think if you have been using Tretinoin for a while and are able to use it daily without any irritation then it is worth a go (patch test first). But if you get a bit of irritation using it normally probably give it a miss.