Simple way: look at the ingredients list. If the ingredients list says that vitamin C and vitamin E are basically synthetic, Neptune should be such a product; The ingredient list of Yangshengtang VC is written by acerola cherry's extract, in which all the vitamin C comes from it, which is more natural, easier to absorb and the effect should be better; In addition, vitamin E depends not only on the source of raw materials, but also on the content of effective component d-α- tocopherol (the higher the content, the better), and also on the auxiliary materials in the product, such as linoleic acid and linolenic acid, which can play a better synergistic role with vitamin E.