Abstract: The moisture retention capacity and safety evaluation of poly-γ-glutamate (γ-PGA) were studied by using CM825 skin moisture tester and the human skin patch test method.Results showed that γ-PGA with separate molecular weight and separate mass fraction displays rather different moisturizing properties respectively,and γ-PGA with molecular weight of 1 200 kDa and mass fraction of 0.1% displays the best moisture retention capacity.After smearing test with the γ-PGA for 2 and 4 h separately,change of skin moisture content becomes (103.9±0.2)% and (112.2±0.2)% respectively,which is near to the value of the widely used moisturizer sodium hyaluronate (114.0±0.3)%.Results of the skin patch test showed that the γ-PGA is safe and causes no irritation to human skin.

Key words: poly-γ-glutamate, moisture retention capacity, safety evaluation