The super high molecular weight Sodium Polyglutamate (PGA-SHM) is a polypeptide biopolymer produced through the fermentation of the probiotic “Natto Bacillus”. The molecular weight of PGA-SHM is more than 2 MDa (GPC-MALLS method), so PGA-SHM has a nice silky skin feeling and a better film-forming ability which protect the skin barrier from pollution damage. By a series of researches, it has been found that PGA-SHM can effectively promote the generation of natural moisturizing factors (NMF), and enhance significantly the skin barrier function.