Silicon is the 2^nd most abundant element in the earth's crust (after oxygen) and an essential element for both animals and plants.

Several biological roles for silicon have been defined, largely on the basis of animal studies. The most important functions appear to be in the growth and development of bone, cartilage, and connective tissue, where silicon plays both a metabolic and structural role. In bone, silicon is localized in the active growth areas where it is thought to promote growth and hasten mineralization. In cartilage and connective tissues, silicon is a component of proteoglycan complexes that interlace with collagen and contribute to structural integrity. Some researchers have theorized that silicon-oxygen bridges (-O-Si-O-) - the foundational molecule of quartz - may also play a structural role in certain mucopolysaccharides found in connective tissues.

Silicon also appears to be required for the synthesis of collagen. Collagen is the protein matrix found in connective tissue and cartilage, and it is the single most abundant protein in the human body. Silicon promotes the synthesis of proline and hydroxyproline, principal amino acids in the structure of collagen.

Dietary silicon appears to be well-absorbed. Beverages (including beer and coffee), grain, grain products and vegetables are the best food sources of silicon.

Due to a lack of data indicating adverse effects of silicon, no UL has been established.