Vitamins are divided into water-soluble vitamins that are easily soluble in water, such as B group, vitamin C and fat-soluble vitamins A, D, E and K that are easily soluble in oil. Tips for choosing vitamin products. Remind you whether the product packaging is complete, whether the name and address of the manufacturer are marked, and how long is the shelf life. 2 1 Jin Weita, Yangshengtang, vitamins, Jin Erkang, Shancun, and Amway Nutrilite are well known. You can look at the list of brands of vitamins bought online by China brands and compare them.