In male clinics, we often encounter patients who suffer from erectile dysfunction (ED), non-ejaculation or retrograde ejaculation, and even poor semen quality, and are unable to have children, which is found to be diabetes after examination. This article provides a brief introduction to the effects of diabetes on the male reproductive system. What is diabetes? Diabetes is a systemic metabolic disorder characterized by a chronic increase in blood sugar. In general, men often have elevated blood glucose after the age of 40, mainly due to genetics, age, lifestyle, obesity and other factors, from the dysfunction of the pancreatic tissue, an important endocrine organ in the body, which makes insulin secretion insufficient. Its incidence is increasing year by year, and there is a trend of youth. The World Health Organization has predicted that by 2030, there will be 366 million people with diabetes worldwide. Diabetes can lead to decreased fertility in older men, and the incidence of infertility due to diabetes is about 35%. Diabetes can lead to decreased sexual function in men Diabetes can lead to decreased sexual function in men, including decreased libido, erectile dysfunction, retrograde ejaculation, non-ejaculation, and premature ejaculation. Affects decreased or absent libido: Testosterone is an important androgen in the male body and is associated with libido. The hyperglycemic state of diabetic patients can often lead to abnormalities in reproductive endocrine secretion, resulting in lower levels of FSH and LH secreted by the pituitary gland, leading to decreased testosterone secretion in men; at the same time, male diabetic patients often have a decrease in the number of testicular interstitial cells and structural changes, leading to a decrease in testosterone synthesis. Reduced testosterone levels lead to decreased or lost libido. Affects ED: ED occurs in about 1/3 to 1/2 of men with diabetes; and 40% of those with ED are diabetics. The combination of vascular, neurological and endocrine factors contribute to the occurrence of ED in men with diabetes. The essence of penile erection is a local hemodynamic change in the penis, in which the blood vessels of the penis are filled with blood and the veins are compressed and occluded, causing the penis to fill with blood and swell. The occurrence of this process depends on neurohumoral regulation and sound vasodilatory function. The disturbance of glucose and lipid metabolism in the body due to diabetes is often complicated by vasculopathy, with changes in the microstructure of local blood vessels in the penis and a decrease in the number of cavernous smooth muscles, which affects the normal erectile function. In addition, the regulation of the erection process requires the joint participation of somatosensory, central nervous system and peripheral nervous system, the continuous hyperglycemic state of diabetes causes neurological dysfunction and structural changes, resulting in abnormal neural regulation of erection and the occurrence of ED. Causes retrograde ejaculation or non-ejaculation: Some senior male diabetics will develop retrograde ejaculation. When normal ejaculation occurs, the sympathetic nervous system of the pelvic floor controls the closure of the bladder-spreading muscles to avoid retrograde flow of semen into the bladder. In contrast, diabetic patients with pathological changes involving the relevant nerves, resulting in autonomic dysfunction, can cause retrograde ejaculation. In addition, premature ejaculation in men with diabetes may be related to psychological factors, and may also be an early symptom of ED. Diabetes can lead to male infertility Diabetes can cause infertility due to reduced sperm concentration, reduced viability, and increased malformation rates. The excessive oxidation of glucose in the body produces a large amount of reactive oxygen species (ROS), which changes the oxidative stress environment and increases the rate of sperm malformation and DNA fragmentation; the continuous hyperglycemic state disrupts the reproductive endocrine axis in men, causing a decrease in testosterone secretion and an increase in apoptosis of male spermatogenic cells, resulting in a decrease in the number of spermatogenic cells and a decrease in sperm concentration. Ultrastructural analysis of the spermatozoa shows an increase in sperm defects in diabetic patients, including altered sperm acrosome and increased DNA fragmentation rate, all of which affect sperm-egg binding and lead to decreased female conception rate. Moreover, the older the male diabetic patient is, the lower the semen volume; the longer the duration of diabetes, the lower the sperm viability. Seminal plasma contains nutrients for sperm such as fructose and zinc, and glucose is a precursor for fructose production, so abnormal glucose levels in diabetic patients will also cause abnormal fructose levels in the patient’s seminal plasma, resulting in changes in the proportion of components in seminal plasma. Therefore, the impact of high blood sugar status in men on reproductive function cannot be ignored. Strict control of blood sugar is the only way to restore normal sexual function and fertility.