Why do underwire bras poke you?

One of the primary grievances with underwire is that it can poke through the bra and hurt your skin. As the bra wearer moves, it creates opportunities for wire to move around and poke through.

To avoid this, bra manufacturers will cover the ends of the wires with different materials, like silicone. Some brands will also shorten the length of the underwire to give a bit more leeway and add a bit more of a cushioned underwire casing so it’s stronger, more comfortable, and less easily punctured by the wire.