How do you know if you're applying all of those serums, gels and lotions in the right order? Because putting them on incorrectly could mean poor absorption of that expensive serum, which just means money down the drain. Honestly, this is something that even doctors get confused about.
Skincare products are different than the drugs that I prescribe my patients every day. Typically I am dealing with only 2 different routes of delivery- Oral vs Intravenous. So, I usually only have to think about how well the stomach/intestine will absorb something.
However, skincare (and topical drugs for the skin) have many different formulations. Serums, gels, lotions.... they all absorb into the skin differently in terms of depth and time period. In fact, it is the formulation (or as Dr. Schultz calls it, the vehicle) that is much more important than even the percent active ingredient.
Dr. Schultz's newest video over on DermTV is a great explanation of this problem. I hope it helps relieve some confusion!
DermTV: What Order to Apply your Skincare