This is an in-depth review of this serum, which I use in my 5-Step Japanese Skincare Routine. This is the third step in the process, with the order being: cleanser, toner, serum, eye cream, face cream. I have never used a serum before and was initially intimidated by the word "acid" and the fact that it came in a medicinal looking dropper bottle. But so far I have really enjoyed this addition to my daily skincare routine. Not only do I have combination skin due to my Japanese-American genetics, but I'm also allergic to everything and live in both dry, cold Colorado and hot, humid Georgia. I've been hunting a whole set of products to create the ultimate skincare package. We all have hyaluronic acid in our bodies already, but is generally taken as a supplement to help with joints. Instead of injecting this into my knees, I'm patting it all over my face to help with dry skin. It's supposed to be great for people with eczema or skin problems. I'm using it to help prevent signs of aging, and to improve my combination skin and overall skin ton