Silica, also known as silicon dioxide, is a mineral often included in supplements marketed for nail health. Scientifically, silicon is considered an essential trace element involved in the synthesis of collagen, glycosaminoglycans, and possibly the structural integrity of nails, skin, and hair. Some small clinical studies and observational research suggest that silica supplementation may improve nail strength and reduce brittleness. For example, a few studies have reported mild improvements in nail fragility with silicon supplementation, especially in individuals with brittle nails, but these studies tend to be small, short-term, or lack robust placebo controls.

The European Food Safety Authority (EFSA) and other regulatory agencies recognize silicon as safe, but evidence is insufficient to draw strong conclusions about its efficacy for nail health. The mechanisms by which silica might benefit nails are plausible, as silicon is present in connective tissue and may contribute to keratin structure. However, high-quality, large-scale clinical trials are lacking. Most of the scientific validation is preliminary or based on mechanistic reasoning rather than definitive human outcomes.

In summary, while there is some scientific rationale and limited supporting evidence for silica’s role in nail health, the overall quality and quantity of evidence is modest at best. Its use is more justified by mechanistic plausibility and small studies than by robust clinical validation.