Breast changes in adolescence: From the age of 9 to 10 years old, breasts are stimulated by hormones secreted by the ovaries, the nucleus of the breast appears and slowly increases in size, and is basically formed by the age of 15 years old. However, at the beginning, the breasts are more resilient because of the low content of fat cells. Some people may have two breasts of different sizes, and with the development of the body, this difference will disappear naturally. Care principle: seize the opportunity to assist in development. 1, the size of the breasts, although it has a lot to do with heredity, but at this point in time to lay a good foundation will also appear to be superb. We can make efforts in two aspects, one is to do more chest exercises, such as push-ups, swimming and various ball games, and keep the chest and abdomen at all times; the second is to pay attention to balanced nutrition, not partiality, especially to supplement enough fat and water. 2, wear Bra at the right time. wear bra too late to affect the shape, too early to hinder the development, wear time can be judged according to this: nipple becomes obvious, running when the breast shaking, breast outline obvious. If the difference between the upper and lower bust is greater than 16 centimeters, you can also wear a bra. In addition: the bra should not be too tight, do not wear a bra for more than 12 hours a day, every three or four months to re-measure the bust in order to replace.