After hearing about this cream on a highly-reputable Dermatologist's blog, I decided to purchase it to use before applying my Retin-A at night. Prior to using this cream with my Retin-A, I was unable to tolerate the medication. As long as I apply the Replenix cream first, I have virtually no irritation at all. And this is not because the Replenix Cream is blocking the Retin-A; it is instead acting as a buffer for the medication. My skin really loves this stuff and I am so excited that I am able to now use the Retin-A for anti-aging! As for my nighttime routine, I wash my face with a gentle cleanser, immediately apply the Replenix Cream, wait 15-20 minutes, then apply my Retin-A. In the mornings, I use the Replenix cream under all of my other products to act as a potent anti-oxidant against daily skin stressers. And I always use sunscreen/sunblock to protect my skin from premature aging and skin cancer! Why take such great care of your skin and then throw it all away by not using sun protection?!