Pfizer is an American pharmaceutical company founded in 1849. It is best known for developing popular drugs like Lipitor, the best-selling drug of all time for lowering cholesterol. Lipitor's active ingredient, atorvastatin, was invented in 1985 by Bruce Roth and works by inhibiting cholesterol production in the liver. It proved more effective at reducing LDL cholesterol than previous statins, contributing to Pfizer's success. Ian Read currently serves as Pfizer's Chairman and CEO.