After a woman enters puberty, the mammary glands develop and mature under the action of estrogen. In addition to genetic factors, estrogen levels often directly determine the size and fullness of the breasts. The counter-example is that after a woman enters menopause, her breasts shrink and sag due to a significant drop in estrogen levels. Soy milk, on the other hand, contains a small amount of phytoestrogens, the main ingredient being soy isoflavones, a compound with weak estrogenic effects. Is it the culprit in the news that leads to male breast development, as well as the legendary breast enlargement tool for girls? Compared with the human body’s physiological secretion of estrogen, phytoestrogens just have a similar molecular structure that can bind to estrogen receptors in the body and produce estrogen-like effects, but the effect is much weaker than that of real estrogen. Therefore, in this sense, the role of phytoestrogens in the body is biphasic: a, when the body’s estrogen content is very low, it can play the role of supplemental estrogen; b, when the body’s estrogen content is very high, due to its binding to the receptor impedes the normal combination of physiological estrogen and the receptor, but instead of inhibitory effect, equivalent to reducing estrogen levels, weakening the role of estrogen. Through the above analysis, we can get such a conclusion: for is in full swing, surging secretion of estrogen in the full bloom of the girls, by drinking soy milk, or supplementation of phytoestrogens, can not play a role in raising the level of estrogen in the body, to promote the role of breast development. So, do not drink soy milk, direct supplementation of estrogen? It must be seriously and solemnly explained: although estrogen is very important for women’s growth and development as well as the prevention of many diseases, excessive estrogen levels are also a trigger for breast cancer, endometrial cancer and other diseases. Therefore, not only the majority of middle-aged and young women can not supplement estrogen at will, even for the body estrogen level is very low menopausal women, in order to alleviate menopausal syndrome and take estrogen supplementation therapy must also be cautious and cautious. Can soy milk broaden men’s “chest”? In fact, the content of soy isoflavones in soymilk is very small, less than 100μg/ml, usually drink 200ml of soymilk a day, intake of soy isoflavones less than 20mg, even according to the news of the man’s practice, drink to 1000ml a day, soy isoflavones intake is only 100mg. Perhaps we have little perceptual understanding of these figures, we can refer to the Chinese Nutrition Society Prepared by the Chinese residents dietary guidelines, it is recommended that people consume soy foods 40g per day, according to the soybean isoflavones in the content of 3.5mg / g calculation, 40g of soy foods containing soy isoflavones 140mg, which is of course a reasonable and safe intake. Therefore, the gynecomastia simply attributed to drinking soy milk, which is a lack of evidence, not rigorous enough. Clinically, gynecomastia is not rare, and can occur in newborns, adolescents, and middle-aged and older men, and there are many causes of the disease. In middle-aged and elderly men, breast development may also be caused by the presence of varying degrees of declining testicular function, lower testosterone levels in the blood, weakened circadian rhythms, and lower androgen/estrogen ratios. Of course, eating a single food for a long period of time and in large quantities can cause excessive intake of certain nutrients. But we should not blindly exaggerate the dangers of soy milk for the purpose of curiosity and attracting attention, so as to cause unnecessary panic among men and unrealistic expectations among girls.