Abstract Body: The increase in average life expectancy is a reflection of numerous advancements in medicine, healthcare, sanitation, nutrition, and technology. As life expectancy increases, women are spending approximately more than one-third of their lives with menopause. The focus of this study is to understand how menopause influences cardiovascular health, later in life. We are revisiting the potential of hormone therapy once the role of 17β-estradiol (estrogen, E2) replacement therapy (ERT) during menopause is controversial. Research findings have fluctuated from relieving menopausal symptoms to benefits for bone and cardiovascular health while other studies suggest a link to increased breast cancer and heart disease risks. Here we investigated the role of ERT on atherosclerosis formation using an in vitro model of menopause. Our results showed estrogen therapy markedly decreases oxidized low-density lipoprotein (oxLDL) uptake/ transcytosis and changes monocyte adhesion in human aortic endothelial cells (HAECs). Our results showed that treatment of aortic endothelial cells with physiological levels of estrogen reduced oxidative stress by preventing superoxide production. Additionally, estrogen treatment led to mitochondrial fusion in our model. The movement of LDL (low-density lipoprotein) across the endothelium and its subendothelial retention is critical for the initiation of atherosclerosis. The reduced internalization of oxidized lipoproteins by endothelial cells under estrogen treatment prevented the stimulation of ROS-generating signaling pathways and further endothelial damage. Collectively, this study suggests that our in vitro model of menopause using human aortic endothelial cells recapitulated the beneficial role of estrogen therapy from previous studies. While allowing the mechanistic investigation of cell biology and signaling.