Skin Gland Fat. Breast sagging in men is caused essentially by overgrowth of the breast tissue (gland) associated with an increase in the fat in and around the parenchyma and is aggravated by skin laxity. This can be due to aging, weight gain/loss, hormonal, conditions, medications, drugs, congenital disease, atrophy of tissues (fat/breast/ muscle) as well as a variety of other causes.
Fat. Breast tissue and fat.