Simvastatin acts primarily in the liver, where decreased hepatic cholesterol concentrations stimulate the upregulation of hepatic low density lipoprotein (LDL) receptors which increases hepatic uptake of LDL. Simvastatin also inhibits hepatic synthesis of very low density lipoprotein (VLDL). The overall effect is a decrease in plasma LDL and VLDL. Simvastatin, treats high cholesterol by reducing the amount of bad cholesterol in your blood. You take it to protect yourself from building up fats and cholesterol that slow down blood flow. Exercising and eating fewer fats are important parts of your treatment with simvastatin. All of these can help prevent heart attack and stroke.