Parakeratosis inhibitor, pore -shrinking agent and external compositon for skin

A parakeratosis inhibitor agent, pore-shrinking agent, or rough skin preventing/ameliorating agent comprising one or two or more compounds selected from a group consisting of β-alanine derivatives represented by the following general formula (1), (2) or (3), and salts thereof.

• (In general formula (1), X and Y each independently represents an oxygen atom (O), a nitrogen atom (N), a CHQ group (in the group, Q represents a hydrogen atom (H) or an alkyl group having 1 to 3 carbons, or hydroxyl group), or a carbonyl group (C═O). Z represents a methylene group (CH2), an ethylene group (CH2—CH2), CH═CH, or a benzene ring. j and m each independently represents an integer of 0 to 5. The total of j and m, (j+m), is 0 to 6.)
• (In general formula (2), R1 and R2 each independently represents a hydrogen atom, alkyl group having 1 to 3 carbons, or alkenyl group having 1 to 3 carbons. R3 and R4 each independently represent a hydrogen atom, alkyl group having 1 to 3 carbons, alkenyl group having 1 to 3 carbons, cyclohexyl group, or a group containing nitrogen atoms and forming a cyclic structure by R3 and R4. The total number of carbons in R3 and R4 is 0 to 6.)
• (In general formula (3), R5 and R6 are each independently a hydrogen atom, alkyl group having 1 to 7 carbons, alkenyl group having 1 to 7 carbons, hydrocarbon group having 3 to 7 carbons and having a cyclic segment, pyridyl group, cyclohexylcarbonyl group, cyclopentyl carbonyl group, nicotinoyl group, isonicotinoyl group, picolinoyl group, nipecotinoyl group, isonipecotinoyl group, N-acetyl nipecotinoyl group, N-acetyl isonipecotinoyl group, benzyloxycarbonyl group, a group represented by general formula (4)
• (In general formula (4), R7 through R11 each respectively and independently represents a hydrogen atom, hydroxyl group, alkyloxy group having 1 to 4 carbons, alkenyloxy group having 1 to 4 carbons, alkyl group having 1 to 3 carbons or alkenyl group having 1 to 3 carbons. n represents an integer of 0 to 2, and p represents an integer of 0 or 1), or a group represented by general formula (5)
• (In general formula (5), R7 through R11 and n are the same as those in general formula (4)). R5 and R6 cannot be both hydrogen atoms at the same time.]