The thickness of a piece of jewelry is specified as a Brown and Sharp gauge number. The thinner the wire, the sharper it is when pulled or twisted in a piercing. As the thickness of the wire increases (lower gauge number), the more the mechanical force is spread out over the supporting tissues, and the less likely are bruising or cutting to occur. Although the minimum gauges (maximum number) for the various tissues are specified to improve the likelihood of success for the piercing, the problems associated with thinner wires are not necessarily eliminated with the thicker wire, merely less likely. The following rules of choice are based on experience and represent a trade-off between the client's wish to minimize the ring size and the piercer's desire to minimize the cutting or bruising which will result in aftercare problems and ring migration.

The minimum gauge of wire should be 14G or 1.6mm (1/16"). SMALLER GAUGES TEND TO BE REJECTED (HEALED OUT) BY THE BODY, MUCH THE SAME AS WOULD A SPLINTER. THE METAL THROUGH THE PIERCING MUST BE THICK ENOUGH TO PREVENT THE REJECTION PROCESS.