Low HDL cholesterol can be categorized into physiological and pathological, physiological is common in people with less exercise, and pathological is common in diabetes, coronary heart disease, cirrhosis and other diseases. The normal range of HDL is 1.04-1.55mmol/L, generally less than 1.04mmol/L is considered low. HDL cholesterol is mainly synthesized by the liver and small intestine, and is the smallest lipoprotein. HDL cholesterol can reduce the concentration of cholesterol in peripheral blood and prevent atherosclerosis. It is known as the “good cholesterol”. Numerous studies have shown that a decrease in HDL cholesterol reflects “insulin resistance” and is one of the risk factors for diabetes. Lower HDL cholesterol, which is the main mechanism of anti-atherosclerotic and vasculoprotective effects, also increases the risk of atherosclerotic cardiovascular disease. If you have low HDL cholesterol, you need to go to the hospital to be evaluated by a doctor and a treatment plan should be developed.