THYROID FUNCTION

Silicon

Si — Element #14

also known as Orthosilicic acid, Silicon dioxide, Silica, Bioavailable silicon

The second most abundant element in the earth's crust, present in trace amounts throughout the body. Silicon is not formally classified as essential for humans, but emerging research suggests a role in connective tissue, bone, hair, skin, and nails — particularly through the form called orthosilicic acid found naturally in beer, oats, and bananas.

Role in the body Likely supports collagen cross-linking and bone matrix formation; not formally classified as essential but probably beneficial

Recommended daily intake

Adequate Intake · No formal RDA established; estimated 20-50 mg daily from typical Western diets

Upper intake limit

Not formally established

Signs of deficiency

Not formally established in humans
Animal studies suggest impaired bone, cartilage, and connective tissue development with severe deprivation

Supports collagen formation and connective tissue strength
May support bone density when consumed regularly through diet
Associated with hair, skin, and nail strength in observational research
Found naturally in oats, barley, bananas, leafy greens, and surprisingly in beer (one of the richest dietary sources)
Horsetail and bamboo extract are concentrated supplemental sources of plant silicon
Most people get adequate silicon from diet without supplementation

Active in Si(OH)₄ (orthosilicic acid), SiO₄⁴⁻ (silicate).

Not formally classified as essential — no RDA has been set, but adequate intake estimates exist

Horsetail (a common silicon source) carries its own safety concerns including a vitamin B1-depleting enzyme

Choline-stabilized orthosilicic acid is the form best absorbed; cheaper silicon dioxide supplements are mostly inert

Inhaled silica dust (a different exposure entirely) causes silicosis, a serious lung disease — relevant to construction and mining, not dietary silicon

Generally well tolerated as food or properly formulated supplement

NCBI — Silicon in Human Health · NIH — Dietary Reference Intakes Background on Silicon · Britannica — Silicon

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