Estrogen is mainly secreted by the ovaries, and to a lesser extent by the adrenal cortex, placenta, and testes, and is a derivative of cholesterol, also known as a prohormone. Therefore, estrogen is also present in men. There are two sources of estrogen in the male body, one third comes from the testes and two thirds is converted from androgens outside the testes. In addition, white pollution in the environment and diet, mainly estrogen-like substances, further exacerbates the increased estrogen levels in the body. Many men have increasingly high levels of estrogen in their bodies, some even several times higher than normal, and these high levels of estrogen happen to be a risk factor for male infertility and sexual dysfunction. In general, the male body maintains a balance between androgens and estrogens, both of which play an important role in the reproductive system. Once this balance is disturbed and estrogen levels rise, it can be extremely harmful to men of all ages. First of all, for children, there is now a significant increase in occult penis (short penis) than before. While this is certainly related to the increase in “chubbiness”, it cannot be ruled out that it is partly the result of increased estrogen in the body. Secondly, the rise in androgen levels will affect male pubertal development, inconspicuous secondary sexual characteristics, and lack of masculinity. For young and middle-aged people, when they reach the marriage and childbearing period, men may have sexual dysfunction and abnormal semen quality due to high estrogen levels. In addition, changes in the ratio of estrogen to androgen will inevitably lead to changes in testicular tissue structure, which may induce other diseases. In normal men, testosterone (androgen) can be converted into estradiol (estrogen) under the action of aromatase. Excessive increase of estrogen in men’s body is mostly related to environmental pollution, illegal food additives and poor lifestyle, in addition to some endocrine diseases. If the body’s estrogen is too high, the balance between estrogen and androgen is out of balance, which can easily induce obesity, spermatogenic dysfunction or cancer, and in serious cases, infertility. 1. Excessive fat in obese people will increase the storage of estrogen or allow too much androgen to be converted into estrogen, thus leading to higher estrogen levels in the body and prolonged action time. 2. Estrogen can stimulate male breast development, and high levels can easily induce breast cancer. Most breast diseases are caused by high estrogen levels and endocrine disorders. 3. Estrogen and androgen act together on the spermatogenic function of testes. If estrogen increases relatively, the spermatogenic environment will change and spermatogenic disorders will be easily induced. When the pace of life is faster, mental stress is high, and human resistance is poor, it will promote endocrine disorders. In today’s society, men’s work pressure and lifestyles have changed a lot. Lacking exercise and labor, this lifestyle can easily lead to weight gain or obesity and abnormalities in lipid metabolism, which in turn affects estrogen-androgen metabolic disorders i.e. lower androgen levels and higher estrogen levels. Although abnormal estrogen levels in men can lead to a range of problems, the severity of the problem is subject to further epidemiological studies. Therefore, there is no need to panic in men with high estrogen levels, as some of them can be improved and regulated to normal physiological levels through a healthy lifestyle. For infertile patients, especially those with more serious conditions, aromatase inhibitors (Fury, Letrozole, etc.) can be used to lower estrogen and increase androgens. Once hormone levels return to normal and the environment for sperm production is improved, it is still possible to restore fertility.