A compression vest or gynecomastia vest is a specialized compression garment for men with gynecomastia, a condition characterized by the development of breast tissues in males. [1] [2] The estimates of those with the condition are presented as a range "because the definition of gynecomastia varies and the method of surveying varies." [3] Although there are options for treating gynecomastia, [4] some individuals opt to wear a breast compression garment as a non-surgical alternative for compressing the breast. [1] Compared to bras, these vests typically flatten rather than lift. [5]