Very few metals and alloys have been proven safe and effective for initial wear in piercings. For acceptable body jewelry materials, our industry utilizes the materials guidelines established for medical implants as defined by the ISO and ASTM, along with materials that have a history of documented compatibility with the human body such as gold, platinum, and niobium.
The International Organization for Standardization (ISO) was founded in 1947 and is the world’s largest developer of voluntary international standards. Their mission is to promote the development and distribution of international standardization for scientific and technological practices; including medical, metal, and chemical activity. ISO has published over 19,000 standards to date. There are currently members in 164 countries.
ASTM International, formerly the American Society for Testing and Materials (ASTM), is a not-for-profit organization that provides a global forum for the development and distribution of consensus standards for materials and testing. There are more than 150 nations and over 30,000 technical experts and business professionals working together in a transparent and open process to create internationally accepted standards that are used in scientific and medical fields.
Use of ISO and ASTM International standards are voluntary. They only become legally binding when a contract or a governmental body cites them. Manufacturers in a variety of industries may state a product has been tested according to ASTM or ISO standard by citing the applicable code number on the product label or packaging. With metals, both pure elements and alloys, this will appear on the mill sheet.
Often referred to as a "mill certificate," "mill sheet," or "material certificate," this is a document provided by a metal foundry. It guarantees the specifications of the metal and is proof of content. On request, any company producing jewelry must provide a copy of the certificate(s) obtained from the foundry where their raw material was purchased. If a jewelry manufacturer is unwilling or unable to produce this certification, their jewelry cannot be considered to meet ASTM or ISO specifications. Information that should be on any material certificate includes the contact information for the supplier, tester, and buyer; the ASTM or ISO standard that relates to human implant, and the size (gauge), quantity, and composition of the material. Unless a jewelry manufacturer machines all of their jewelry out of solid stock, they must have mill certificates that correspond to each thickness of material purchased for jewelry that is sold for use in initial piercings. Some regulations now require that studios provide certification proving ASTM/ISO compliance (and therefore the biocompatibility) of their jewelry.
In addition to ISO 10993 evaluation, other informational certificates are available for glass including Registration, Evaluation, Authorisation and Restriction of Chemical substances (REACH),84 and Restriction of Hazardous Substances (RoHS).85 These show the levels of any hazardous materials such as lead, cadmium, and/or arsenic potentially released by the material.
The following is the list of approved certified materials for use in a new piercing. Check the APP website for any updates or revisions to this list:
Any plastic material that is ISO 10993-6,96 10993-10,97 and/or 10993-1198 compliant and/or meets the United States Pharmacopeia (USP) Class VI99 material classification
All threaded or press-fit jewelry must have internal tapping (no threads on posts)
Low carbon stainless steels such as 316L and 316LVM are used in the body jewelry industry because of their proven biocompatibility. For many years 316LVM was the preferred steel standard for a fresh piercing. Not all 316L(VM) stainless steel will meet ASTM or ISO certification, and as a result they may vary in biocompatibility. Studios must have mill certificates from jewelry manufacturers showing that the steel being used is either ASTM F138 or ISO 5832-1, 10993-6, 10993-10, and/or 10993-11 compliant. Stainless steel contains nickel, which is a well-documented irritant.100 One significant benefit of using implant-certified materials is a passive layer of chromium oxide that allows virtually no nickel to contact the wearer.
Titanium (Ti) is an extremely inert and lightweight element. It can be anodized to create jewelry of different colors. These colors are created by producing an oxide layer. The thickness of the layer will reflect light differently, thus giving various colors. This does not affect the biocompatibility of the metal. Colors may fade with time and certain types of chemical exposure, but this does not affect the safety of the jewelry.101 Commercial Ti alloys such as Grade 5 or Grade 23 on their own are not biocompatible enough to meet the jewelry standards. The materials must comply with surgical implant specifications such as ISO 5832-3, ASTM F67, or ASTM F136 to be considered safe for initial body jewelry.
Gold has been used successfully as piercing jewelry for thousands of years. It is considered by both our industry and the medical field to be biocompatible for most people when pure enough.102 Gold jewelry usually contains a mixture of gold and other metals creating an alloy. Jewelry manufacturers use different alloy mixtures and often guard the recipes as trade secrets. Since the specific percentage of each metal used varies, it has shown to be impractical to set specific requirements for gold. The purest form of gold, 24k, contains no other materials, but is too soft for use in most body jewelry. Soft jewelry may get scratched, nicked, or burred easily, and can be difficult to thread without stripping. Jewelry under 14k should not be used as it contains less than 57% gold and can include amounts of other metals that may cause adverse reactions. Only solid white or yellow gold in 14k to 18k is suitable for insertion into the body in a fresh piercing, when alloyed with other inert elements. Colored versions such as rose or green gold are alloyed with copper, silver, and/or other metals. These alloys are more likely to cause adverse reactions in the body. In the making of white gold alloys, metals such as platinum or palladium are used to make the gold white in appearance. APP standards require that white gold be nickel free.
This is a very heavy and expensive precious metal. It is extremely inert and therefore an excellent choice for body jewelry. It is brilliant white in color and harder to work than other precious metals. Availability of platinum body jewelry may be limited as a result of its greater cost and difficulty in manufacturing due to its high melting point.
Niobium is very similar to titanium, but denser. It is used extensively in the medical industry for implant components and has been the subject of thorough biocompatibility testing. Like titanium, niobium can be anodized to produce different colors. Unlike titanium, it can also be turned black using a heat treatment. Matte black niobium has a rough finish and is not suitable for fresh piercings. After being turned black, niobium can be polished to give a smooth and glossy finish, which is acceptable for use in initial piercings.
Glass made of fused quartz, lead-free soda lime, and lead-free borosilicate are acceptable for initial piercings. These materials are autoclavable and very biocompatible. In smaller sizes they can be fragile and susceptible to breakage. Fused quartz glass is made by melting high purity, naturally occurring quartz crystals together. Soda-lime glass is the most common form of glass produced. Such glasses are made from three main materials—sand (silica-silicon dioxide), lime (calcium oxide), and soda (sodium oxide). The soda serves to lower the temperature at which the silica melts, and the lime acts as a stabilizer for the silica. Soda-lime glass is relatively inexpensive, chemically stable, reasonably hard, and extremely workable.103 Borosilicate is a type of glass that includes at least five percent boron (boric oxide), which makes it resistant to extreme temperatures, and also improves its resistance to chemical corrosion.104 Regardless of other components, glass must be free of lead and other harmful substances to be used in piercings.