Applying an antioxidant serum like vitamin C at night before retinoids can help replenish skin damaged by environmental factors.

“And I always have them put a super antioxidant serum or a vitamin C serum on at night before the retinoid because my feeling on this is that you spend the whole day outside or in your car or um being hit by LED lights and ultraviolet ultraviolet lights, those are also damaging the skin. And so I think you should have an antioxidant on first thing in the morning, but it's going to get depleted by the end of the day. And so by the end of the day, wait, I'm sorry. I missed that. Are we putting the serum on in the morning? Yes. And at night. And I always have them repeated at night because it's depleted all day long.”