What kind of jewelry should I buy?
Implant grade stainless steel jewelry is generally reasonably priced and safe to use for new piercings. Both 316L and 316LVM types of stainless steel meet the standards for "implant grade" that has been approved by the American Society of Testing and Materials (ASTM), an organization that is not related to the government, but sets high standards for all kinds of materials that are manufactured in the U.S. The European organization that is similar to the ASTM is called the "ISO".
Implant grade stainless steel is least likely to produce a foreign body reaction or infection in the skin. Other safe choices for new piercings are metals such as gold (at least 18 karat), titanium, or niobium. All of these cost more than implant grade stainless steel.
Silver is not a good choice for new piercings because the tarnish from silver gets deposited into the skin. The deposits often darken the skin around the piercing, which can be permanent. Sterling silver jewelry can be safely worn on most healed piercings, but it should not be worn in the mouth or genital area where the skin is moist.
Gold jewelry should be at least 18 karat (75% gold) for new piercings and at least 14k gold for healed piercings. Gold-filled or gold-plated jewelry should never be used in any piercings because the metal is very thin. The finish wears away easily and it chips with slightest contact of the body. Some people have difficulty with white gold because it contains "nickel" - a metal that many people are allergic to.
Titanium is used for jewelry and for surgical implants in the body. For example, titanium implants are used for shoulder replacement surgery because they are lightweight and porous. There are actually tiny pores in the metal that allow tissue in the body to attach to it. For this reason, it is recommended that titanium jewelry be highly polished to reduce the "porosity" (pores or very tiny holes in the metal).
For people who are extremely sensitive to metal, teflon or nylon piercings may be used.