To determine whether a man has gynecomastia or fatty breasts can be judged by the cause of formation, touch, accompanying symptoms, mammography and other ways. 1. Formation causes: estrogenized chest is usually caused by long-term use of cimetidine, spironolactone and other drugs that can cause breast development, or suffering from hypothalamic tumors and other diseases; fat chest is usually caused by too much fat in the chest, which is common in the obese people. 2. Touch: If the estrogenized breast has more glands, it is slightly hard to touch, and there will also be breast lumps, breast hyperplasia and other symptoms; fat breast is mainly due to higher fat content, so it is softer to touch. 3. Accompanying symptoms: estrogenized breast is usually caused by excessive secretion of estrogen and other factors, which may be accompanied by symptoms such as loss of libido and reduction of body hair; whereas fat breast generally does not have these abnormal accompanying symptoms. At the same time, breast ultrasound can also determine whether the breasts are estrogenic or fatty; weight loss can significantly reduce the size of the breasts is often fat breasts, and vice versa is estrogenic breasts. Men who need to determine whether they have gynecomastia or fatty breasts are advised to go to the hospital and ask the doctor to make a judgment based on the specific situation.