Abstract: Adopting skin moisture testing instrument and epidermal moisture loss testing instrument,situation with respect to moisture content in human skin as well as epidermal moisture loss after separate use of moisturizing cosmetics containing sodium polyaspartate (PASP) with lower and higher molecular weight as well as different mass fractions were examined.Results showed that PASP with higher molecular weight displays better moisturizing effect on the skin,and its water retention effect is conspicuous.When the content of higher molecular weight PASP in the cosmetics achieves 0.8%,the skin moisture content may increase by more than 0.5%,and its skin moisturizing effect may equivalent to that of hyaluronic acid.Further,in order to examine the elasticity change capacity of PASP,in-vitro water dipping test was conducted adopting skin elasticity testing instrument with pig skin as the substrate.Result indicated that PASP can improve skin elasticity.All the results showed that PASP has good prospects for development in cosmetic industry.

Key words: moisturizing cosmetic additive, sodium polyaspartate, skin care product, moisture content, epidermal moisture loss