Sex specific differences of factor XI and relationship with other coagulation factors

•Increased activity of FXI has been linked to higher risk of thrombotic events•Inhibitors of FXI promise to dissociate pathologic thrombosis from physiologic hemostasis•Sex based differences in risk for ischemic stroke are incompletely understood•We demonstrate higher levels of FXI in women compared to men•Variability of FXI is linked to FXII, prothrombin, antithrombin, fibrinogen, and PAI-1.