The present invention provides a parakeratosis inhibitor, a pore-shrinking agent, and a
rough skin inhibiting or ameliorating agent comprising, as an
active ingredient, a compound that has excellent effects and high safety without safety problems such as sensory
irritation, and provides an external composition for
skin containing the same. The compound is selected from the
glutamic acid derivatives represented by formula (1) or (2) and the salts thereof:wherein A represents a carbamoyl group, a benzyloxycarbonyl group, an
alkyl group having 1 to 3 carbon atoms, an allyl group, or an amidino group;wherein Z represents an
alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, etc.; Y represents OH, an alkyloxy group having 1 to 3 carbon atoms, an allyloxy group, or NR3R4; R1 to R4 each independently represents H, an
alkyl group having 1 to 3 carbon atoms, an allyl group, a cycloalkyl group having 3 to 7 carbon atoms, a cycloalkenyl group having 3 to 7 carbon atoms, a
phenyl group, or a
benzyl group, or R1 and R2, or R3 and R4, independently form a heterocycle.