It is intended to provide a drug, a quasi-drug, a dermatological preparation for external use, or a material to be contained to drugs, quasi-drugs, dermatological preparations for external use, food products, or the like which has an excellent UCP-1 expression-promoting action and promotes conversion of adipose to brown adipose (browning). The present invention provides a UCP-1 expression promoter comprising a PPARγ activator and a Smad3 inhibitor in combination. The present invention also provides a UCP-1 expression promoter comprising a PPARγ activator, a Smad3 inhibitor, and a β3 adrenaline receptor activator or a TGR5 activator in combination.
