PROBLEM TO BE SOLVED: To provide an involucrin expression inhibitor inhibiting expression of involucrin which is a protein produced in spiny cells according to differentiation of an epidermal keratinocyte and related to wavy hair, to provide a wavy hair-improving agent, and to provide a hair-softening agent.SOLUTION: The invention provides an involucrin expression inhibitor containing Potamogetonaceae, Potamogeton, Potamogeton natans or extract thereof as an active ingredient a wavy hair-improving agent and a hair-softening agent. As the Potamogeton natans, a whole plant, a leaf, a stem, a sprout, a flower, a bud, a root, a rhizome, a seed, or a fruit, or the like, or a combination thereof can be used, but use of the whole plant is preferable. They can be used as it is or juice obtained by compressing them, a dry substance obtained by drying the plant itself or a ground product thereof, or extract extracted from these, but use as extract is preferable.COPYRIGHT: (C)2016,JPO&INPIT
