Does breast enlargement pumps work for men?

Probably: Use of the brava type suction systems for creating additional space and vascular supply is most commonly used in post-mastectomy patients in preparation for expansion of tissues for grafting or implants. It's technology should function the same in males, but males often have less fat tissues to glandular, limiting the ability to modify the adipose tissues (expansion) and it's blood supply to area.

For breast, not musc: They will probably work for your breast tissue, fat and nipple and may be good for transgender considerations but if you are using this to increase muscle size, it is unlikely to accomplished this goal.