How do statins primarily lower LDL cholesterol levels?

Statins are effective lipid-lowering agents primarily because they inhibit the enzyme HMG-CoA reductase, which plays a crucial role in the biosynthesis of cholesterol in the liver. By blocking this enzyme, statins reduce the overall synthesis of cholesterol. As a result, the liver senses a decrease in the intracellular cholesterol levels, prompting it to increase the expression of LDL receptors on its surface. This action enhances the clearance of LDL cholesterol from the bloodstream, leading to lower plasma levels of LDL cholesterol.

The primary mechanism of action of statins is tightly linked to reducing cholesterol synthesis rather than affecting the absorption of cholesterol from the diet or altering triglyceride levels. Although there may be some additional effects regarding triglycerides and HDL cholesterol, the principal and most direct method by which statins lower LDL cholesterol is through the inhibition of cholesterol synthesis in the liver.