People of all weights, ages, and sizes can have extra fat or skin around their chests and underarms. Tight clothes can reveal the skin from the chest as the skin gets pushed up and so the armpit fat is seen. Armpit fats are completely normal. This can occur in any gender and it is most commonly seen in women than in men. Body fats are largely due to genetic factors. If you are overweight, fat might get deposited in or under your armpits. Subcutaneous fat gets deposited in your underarm area if you are overweight and this also makes your breast and underarm area larger. Losing weight with dieting and exercising will help you lose underarm fat. Hormonal changes can also be one of the reasons for underarm fat. With pregnancy, puberty, menstruation, and menopause you can probably gain some weight and with the production of estrogen and progesterone, the breasts start to swell. This kind of change increases the look of the excess skin in and under the areas of breasts and underarms. The axillary breast is caused by the growth of breast tissue outside of the normal breast area. This happens commonly in the axilla or armpit. This is congenital and occurs in approximately 2 to 6 percent of women and 1 to 3 percent of men. Losing weight, building muscle mass in your chest wall and upper arms, and wearing properly fitting inner wears can fix all this extra skin in your armpits.