In the past, doctors and scientists all believed that the molecular weight of beta glucan was too large to penetrate into the skin layer. However, the study found that oat beta glucan can penetrate into the skin, and has obvious osmosis on the cuticle and epidermis. The method of osmosis of oat beta glucan does not penetrate the cells directly, but infiltrates into the skin through intercellular space. Just as water penetrates into a brick wall, water does not pass through the brick, but through the concrete that connects the brick body into the wall. Dextran is through the intercellular lipid matrix, also called the intercellular concrete permeated to the bottom of the skin. This is also complementary to the "brick mud model" theory of the skin.