Non-therapeutic use as a skin bleaching agent of a heterocyclic compound represented by formula (1) or a pharmacologically acceptable salt thereof: wherein X1, X2, and X3, are each, independently of each other, CR2 or N； R1, R2, and R3 are each, independently of each other, H, C1-6 alkyl, C1-6 alkoxy, SH, OH, or NRbRc, where Rb and Rc are each, independently of each other, H, C1 alkyl -6, or hydroxy C1-6 alkyl, or NRbRc forming a saturated or unsaturated 5 or 6 element heterocycle； B is a group represented by the formula (B1) or (B2), in which when X1>； = X2>； = X3>； = CR2, B is the group represented by the formula (B1): in which one of Y1 e Y2, is N, and the other being CR5； R4, R5, and R6 are each independently H, C1-6 alkyl, C1-6 alkoxy, C1-7 acyloxy, OH, amino, -NH-A, -NHCOA, or-NHCOCH2-A, wherein A is alkyl C1-6, phenyl, or a heterocyclic group of 5 or 6 elements, where R4 and R5, or R5 and R6, together form a 5 or 6 membered hydrocarbon ring fused to the heterocycle to which R4, R5 and R6 are attached； group (B2) is a saturated or unsaturated 6-membered heterocyclic group； Ra is C1-6 alkyl； and p is an integer between 0 and 2, and if p is 2, Ra can be identical or different； with the proviso that at least one of R1, R3, R4, and R6 is a group other than C1-3 alkyl in case X1>； = X2>； = Y1>； = N and X3>； = CR2.Utilización no terapéutica como agente de blanqueamiento cutáneo de un compuesto heterocíclico representado por la fórmula (1) o una sal farmacológicamente aceptable del mismo: en la que X1, X2, y X3, son cada uno, independientemente entre sí, CR2 o N； R1, R2, y R3, son cada uno, independientemente entre sí, H, alquilo c1-6, alcoxi c1-6, SH, OH, o NRbRc, donde Rb y Rc son cada uno, independientemente entre sí, H, alquilo c1-6, o hidroxi-alquilo c1-6, o NRbRc formando un heterociclo de 5 o 6 elementos saturado o insaturado； B es un grupo representado por la fórmula (B1) o (B2), en la que cuando X1 >；= X2 >；= X3 >；= CR2, B es el grupo rep
