In the present specification is disclosed a melanocyte-stimulating hormone inhibitory composition which comprises, as the active ingredient, a di- or tripeptide derivative having a certain naphthyl group or the salts thereof, or a melanocyte-stimulating hormone inhibitory compound having a 50% inhibitory concentration of cAMP production (IC50) of 100 nM or less, which composition can prevent pigmentation, or can prevent, improve or recover from immune abnormality or immunodeficiency, or regulate body weight by appetite control, and also can be used as cosmetics or external preparations for the skin, and in addition, can be produced easily, and are excellent in the stability during storage.