Abstract-Brown adipocytes can be distinguished from their white counterparts by markers such as UCP-1 or P2RX5. This study cultured brown human adipocytes in growth media containing 0.1 g/L and 1 g/L fructose in addition to glucose and monitored the cell growth. Unexpectedly, the cultured cells co-expressed markers for white adipocytes (ASC-1) and markers for brown adipocytes (P2RX5). Cells developed multilocular lipid vesicles and exhibited similar kinetics of mRNAs involved in lipogenesis with and without fructose. Excessive amounts of fructose induce negative effects on insulin sensitivity, blood pressure, and liver metabolism. These adverse outcomes were attributed to disturbances in key metabolic pathways in the liver. However, possible consequences of high fructose levels when in direct contact with human white adipocytes in vivo have been considered. No such data existed on the effects of fructose on human brown adipocytes. Results indicate that in addition to toxic effects on liver cells, human white and brown adipocytes consume extra fructose and generate new lipid vesicles, further deregulating energy homeostasis.