Glycerin vs Polyglutamic Acid
Glycerin and Polyglutamic Acid are both draws in moisture ingredients. Glycerin is found in 2427 products while Polyglutamic Acid appears in 12, making Glycerin the more widely used option.
Glycerin
One of the most effective humectants
Polyglutamic Acid
Amino acid polymer — holds 5x more moisture than HA