Silicone body jewelry is made from implant grade silicone. It's entirely safe to wear in a healed piercing and is great for people with metal allergies or sensitivities. Anyone can have a reaction to any material such as steel, wood, bone, acrylic etc. but most often the issue with silicone is external debris on the surface. It's also a good substitute for acrylic, since it comes in a wide range of colors and won't react badly with your body. It is great for use during sports or in extreme temperatures.