text: Statins are a competitive antagonists of HMG CoA, as they directly compete with the endogenous substrate for the active site cavity of HMGR. Statins are also noncompetitive with the cosubstrate NADPH (nicotinamide adenine dinucleotide phosphate). By blocking the HMGR enzyme they inhibit the synthesis of cholesterol via the mevalonate pathway. The end result is  lower LDL (Low Density Lipoprotein), TG (Triglycerides) and total cholesterol levels as well as increased HDL (High Density Lipoprotein) levels in serum.