Silica

Silica (silicon dioxide, SiO2) is a mineral marketed for hair, skin, nails, and bone health. The bioavailable form is orthosilicic acid. Silicon is found in connective tissues and may play a role in collagen synthesis. Some epidemiological links to bone health exist, but RCT evidence is limited. Choline-stabilized orthosilicic acid (ch-OSA, BioSil) is the most studied supplement form. Effects on hair/nail quality are modest at best. Safety is generally good but crystalline silica dust (not supplements) causes silicosis.

Quick Answer

What it is

Silica (silicon dioxide, SiO2) is a mineral marketed for hair, skin, nails, and bone health. The bioavailable form is orthosilicic acid.

Key findings

Grade C: Bone Mineral Density
Grade C: Hair and Nail Quality
Grade D: Aluminum Absorption

Safety

No specific caution or interaction language was detected in the current summary/outcome notes.

ℹ️ Quick Facts: Silica

Quick Facts: Silica

Best Evidence:Grade C
Conditions Studied:1
Research Outcomes:4
Key Effect:Bone Health

Outcomes by grade:

1 conditions · 4 outcomes

Detailed Outcomes

Bone Mineral Density

Population-based epidemiological studies (including Framingham cohort data) link higher dietary silicon intake with better bone mineral density, particularly in premenopausal women. One RCT in osteopenic women showed improvement in bone formation markers with ch-OSA added to calcium/vitamin D supplementation versus calcium/vitamin D alone.

300 participants

small↑Improves

Hair and Nail Quality

Small human trials of choline-stabilized orthosilicic acid (ch-OSA) showed modest improvements in hair tensile strength and reduced nail brittleness. Effects were statistically significant but not dramatic, and study sample sizes were limited.

120 participants

small↑Improves

Aluminum Absorption

Mechanistic and preclinical studies suggest silicon may bind dietary aluminum and reduce its gastrointestinal absorption or increase urinary excretion. This has theoretical relevance for aluminum-related neurotoxicity, but clinical evidence in humans is lacking.

small↓Worsens

Skin Elasticity

Limited data from a small human study suggests ch-OSA supplementation may improve skin elasticity and reduce skin roughness. Silicon is a component of glycosaminoglycans in connective tissue, providing a plausible mechanism, but clinical evidence remains preliminary.

50 participants

small↑Improves

Evidence by Condition

Best grade per condition (each condition may have multiple outcomes)

CBone Health

1 outcome · 4 studies

↑Bone Mineral DensityImproves

Research Citations (3)

Water-Dispersible Rhodamine B Hydrazide Loaded TiO₂ Nanoparticles for Turn On Fluorimetric Detection and Imaging of Orthosilicic Acid Accumulation In-Vitro in Nephrotoxic Kidney Cells.

Journal of Nanoscience and Nanotechnology (2018)

PMID: 30189931

Secondary structure and dynamics study of the intrinsically disordered silica-mineralizing peptide P(5) S(3) during silicic acid condensation and silica decondensation.

Proteins (2017)

PMID: 28799215

Emission, fate and effects of soluble silicates (waterglass) in the aquatic environment.

Environmental Science & Technology (2004)

PMID: 14750728

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