Low libido in men is a state in which the level of expression of sexual behavior and the ability of sexual activity in men is reduced, and the sexual desire is inhibited to varying degrees. Those who do not induce sexual desire under appropriate stimulation for a long period of time are called asexual, but should be distinguished from changes in sexual desire due to increasing age and individual differences. The causes of low libido are complex and can be organic or functional. Ageing, physical weakness, lack of labor exercise, cortical dysfunction, testosterone level reduction or some endocrine dysfunction diseases, male reproductive system diseases can make low libido. With the growth of age, after 40 years old often feel sex drive, sexual frequency, erectile hardness compared to the previous slightly reduced, to 50 to 60 years old more obvious. This phenomenon of gradually decreasing libido with age cannot be considered pathological, but a physiological change in male sexual response. The body suffers from systemic diseases, poor nutritional status, weakness, sexual desire is also cold; cerebral cortex dysfunction, the inhibition of sexual excitability is strengthened, and the whole process of sexual function is affected when the inhibition is strong; mental and psychological state disorders, and even abnormalities can also lead to low sexual desire; endocrine dysfunction, such as low testosterone level, low thyroid function, low pancreatic function, can make the original The effective stimulation can not produce enough sexual excitement to sexual organs and sexual reflexes, causing sexual dysfunction; male genital system diseases such as prepuce, small penis, huge inguinal hernia, often make sexual intercourse difficult or unable to have intercourse, and also cause low libido; some drugs such as ethanol, anti-hypertensive drugs, etc. can also cause low libido. In short, the causes of low libido are many, most of them are functional lesions, of which the dysfunction of the cerebral cortex is the most common, and a few are caused by endocrine dysfunction.