The nuclear hormone receptor peroxisome proliferator activated receptor- (PPAR-γ) plays an important role in the regulation of insulin sensitivity. Several studies have shown the ARBs telmisartan and irbesartan potently induces PPAR-γ activity, promoting PPAR-γ-dependent differentiation in adipocytes. However, not all ARBs own PPAR-γ activating properties. In vitro studies have shown that significant differences among PPAR-γ activating ARBs are likely caused by their physicochemical properties, and high lipophilicity is required to obtain sufficiently high penetration rates to bind to intracellular PPAR-γ. Losartan at high concentrations could activate PPAR-γ and behaved like partial PPAR-γ agonists. Nevertheless the results of losartan on insulin sensitivity remain controversial.