Zena Cosmetics Serum Ampoules are formulated with hyaluronic acid as the base composition. Each serum has been specially formulated meticulously in laboratories to target a variety of different skin concerns that have been trialled and tested to ensure their effectiveness. Zena Ampoule Serums are highly concentrated and due to low molecules of the formulation, it is safe to use with needle depths from 0.25mm to 3.00mm.