Moisture absorption and retention properties, and activity in alleviating skin photodamage of collagen polypeptide from marine fish skin

► Collagen polypeptides had good moisture absorption and retention properties. ► Collagen polypeptide could alleviate photo-damage. ► The action mechanisms of collagen polypeptide were further studied. ► Collagen polypeptides can enhance immunity and reduce the loss of moisture and lipid. ► Collagen polypeptides can repair collagen and elastin fibres and maintain type III/I collagen ratio.