Since i discovered Skinceuticals many years ago , this is the only item I have been purchasing in a constant basis and I will continue , due to the benefits . So my most loved serum has to be Ta-da! VITAMIN C ANTIOXIDANT SERUM , depending of my skin needs I have used C E FERULIC & PHLORETIN CF but since a couple of months ago I started to develop some blemishes so I tried and finished my sample size of SILYMARIN CF , however since I am using this serum I noticed great improvement , my complexion looks better , brighter and luminous and have less breakouts so I have decided to buy the normal size