Lightening the skin, smoothening skin color irregularities and/or treating senile lentigines comprises administration of a composition (A) comprising biotin compound (I) (biotin and its salts, derivatives and/or its derivative salts). Independent claims are also included for: (1) preparation of (A)； and (2) a kit comprising (A) which comprises (I) and optionally (II) (each if present, stored together in a single formulation or separately in a distinct container) and instructions, advising a consumer how to administer (A). ACTIVITY : Nootropic； Dermatological. The effectiveness of (I) was tested for its skin lightening effect on the hands of human. The results showed that (I) has the ability to lighten the skin naturally after 29 days. MECHANISM OF ACTION : None given.
