Silicone is a synthetic polymer composed of repeating siloxane units, featuring an inorganic backbone of silicon and oxygen combined with organic groups. This structure provides high thermal stability, low chemical reactivity, and flexibility, making it useful across many industries. In medicine, silicone has a dual nature, used in both strictly regulated therapeutic procedures and extremely dangerous, often illegal, cosmetic practices. The safety of “silicone injection” is largely defined by the purity of the material and the volume injected.
Defining Medical Grade Silicone and Regulatory Status
The distinction between safe and unsafe injectable silicone lies primarily in its formulation and purity. Medical-grade silicone meets stringent safety standards, undergoing rigorous testing for biocompatibility. Conversely, industrial-grade silicone is intended for non-medical uses and often contains toxic fillers and additives. In the United States, Liquid Injectable Silicone (LIS) is not approved by the Food and Drug Administration (FDA) for large-volume soft tissue augmentation, such as breast or buttock enhancement, due to serious safety concerns. While silicone implants are FDA-approved, the direct injection of liquid silicone into tissue is treated differently. The FDA has approved two specific forms of highly purified LIS only for a narrow, specialized medical use: intraocular injection.
Approved Medical Applications
The legitimate use of liquid injectable silicone is limited to specialized, small-volume procedures, primarily in ophthalmology. Two forms of highly purified LIS, Silikon-1000 and AdatoSil-5000, are FDA-approved specifically for use inside the eye. This procedure, known as intraocular tamponade, involves injecting silicone oil to hold a detached retina in place during healing following vitreoretinal surgery.
Licensed physicians may also legally use these purified LIS products “off-label” for specific, controlled applications. The most recognized off-label use is the treatment of severe facial lipoatrophy, or the loss of facial fat, often seen in patients with HIV. This application requires a strict protocol known as the microdroplet technique. This technique involves injecting extremely small aliquots of silicone, typically no more than 0.01 milliliters, spaced over multiple treatment sessions months apart to minimize adverse reactions.
The Dangers of Unauthorized Cosmetic Use
The most severe complications stem from the unauthorized use of non-medical grade or contaminated substances for large-volume cosmetic procedures. These procedures are often performed by unlicensed individuals in non-sterile environments, involving industrial-grade silicone that contains impurities that trigger catastrophic tissue reactions. The substance is frequently used for body contouring like buttock and breast enhancement, requiring volumes that far exceed any medically sanctioned dose.
One common long-term complication is the migration of liquid silicone away from the injection site. Since the silicone is not contained within a capsule, it can travel through soft tissue, causing permanent disfigurement or nodules in distant parts of the body. This migration often leads to the formation of granulomas, which are hard, inflamed masses of tissue representing the body’s attempt to wall off the foreign substance. These inflammatory reactions can manifest years after the initial injection, causing chronic pain, infection, and tissue necrosis, or the death of the surrounding skin and soft tissue.
Immediate dangers arise when the injected silicone accidentally enters the bloodstream. If injected directly into a blood vessel, it can travel to the heart and lungs, causing a pulmonary embolism. This systemic complication can also lead to stroke and severe breathing difficulties, and is frequently fatal. The use of unapproved, large-volume silicone injections for cosmetic purposes remains a highly dangerous practice that carries a substantial risk of irreversible injury or death.
Regulated Alternatives for Soft Tissue Augmentation
Several FDA-approved and regulated alternatives exist for soft tissue augmentation that offer predictable results and a higher safety profile. The most widely used options are injectable dermal fillers based on hyaluronic acid. Since HA is a naturally occurring substance, these fillers provide temporary volume correction, lasting from several months up to a couple of years.
Another regulated option is the use of biostimulatory fillers, such as those containing poly-L-lactic acid. These fillers work by stimulating the body’s own collagen production over time to achieve gradual volume restoration. Autologous fat transfer is also available, which involves harvesting the patient’s own fat cells from one area and injecting them into another to enhance volume.