Gynecomastia, often just called "gyno", is every bodybuilder's worst nightmare: unwanted breast tissue growth that can completely sabotage an otherwise dialed-in physique. While estrogen-driven gyno gets most of the attention, prolactin-induced gyno is a sneakier beast, hitting hard when you're least expecting it. This variant stems from elevated prolactin levels disrupting hormonal balance, leading to puffy nipples, lumps, or full-on tissue development.