We know that testosterone is the male sex hormone that “makes a man a man”, and estrogen is typical for the female body. However, limited amounts of testosterone are also released by the woman’s body, and a correspondingly small amount of estrogen is synthesized by the man’s body. Estrogen is an extremely delicate hormone, the balance of which, like all others, must be monitored and maintained in both sexes. The balance of estrogen in a man’s body affects a man’s appearance and health. Violation of the normal level of estrogen content in the body is already indicated as the main reason for the more frequent manifestation of chronic disease conditions in the representatives of the stronger sex. Testosterone and estrogen are very closely related in the body. Even in the structure of their molecules very small differences are observed. In contrast, however, the effects on their body are substantial. Testosterone reflects on every single cell in the male body. Thanks to it, muscle mass is maintained and accumulated. It plays a beneficial role in terms of bone density. It has a positive effect on the heart, brain and blood vessels. Estrogen in the male body is formed from circulating testosterone through the action of the enzyme aromatase. It can also form in the liver, muscles, brain and fat cells in the body. With age, there is a natural tendency for estrogen levels to increase and testosterone levels to decrease. While controlling age is beyond man’s ability, this is not the case with the other essential factor. The male body secretes more estrogen, the more fatty tissue it has. Aging and obesity are one of the most unfavorable combinations for male health, leading to a fatal imbalance between testosterone and estrogen in the male body. The role of the male sex hormone in male health is only beginning to be clarified. There is a 50% chance that testosterone will protect him from developing cardiovascular disease. It supports muscle tone, maintaining normal blood sugar levels and psycho-emotional balance. The development of diabetes is very closely related to an increase in estrogen levels in men. According to leading world experts, higher estrogen impairs the body’s natural regulation of blood sugar, leading to diabetes and heart attacks. On the other hand, research shows that low testosterone is a cause of depression in men. Prostate cancer is one of the most common diseases in men and one of the most common causes of death. Scientific evidence shows that estrogen plays an essential role in the occurrence and development of this cancer. For years, the scientific community considered testosterone to be the culprit in prostate cancer, but today the opinions are that it is the imbalance of estrogen in the male body that is at its root.Doctors are categorical – low testosterone and high estrogen are a key mechanism for the presence of a chronic disease in men. Second part of the material