Simvastatin ammonium salt is primarily used in the pharmaceutical industry as an active ingredient in medications designed to lower cholesterol levels. It works by inhibiting the enzyme HMG-CoA reductase, which plays a crucial role in cholesterol production in the liver. This helps reduce the risk of cardiovascular diseases such as heart attacks and strokes. It is commonly prescribed to patients with high cholesterol or those at risk of atherosclerosis. Additionally, it is used in research settings to study lipid metabolism and the effects of cholesterol-lowering agents. Its stability and solubility make it suitable for formulation into tablets or other oral dosage forms.