Which combinations of active ingredients are beneficial when used with silica?

In cosmetics, combining clay and silica could create an intriguing synergy, although it remains under-documented by scientific studies to date. This combination is based on complementary physicochemical mechanisms and on empirical observations drawn from numerous existing formulations, particularly in masks, mattifying powders, and gentle exfoliants.

Clay, as a mineral raw material naturally rich in silica, exhibits a widely recognized capacity to absorb sebum and adsorb impurities in skincare. It may help unclog pores, eliminate excess sebum, and leave the skin clearer, while providing minerals that can contribute to maintaining healthy skin.

However, these effects are primarily documented through traditional use rather than supported by robust clinical evidence.

The silica, when added as a supplement to a clay-based formula, would enhance several aspects of the treatment’s sensory and technical efficacy. In micronized powder form, it would help mattify the skin even more thanks to its very fine absorbent properties, while improving the product’s feel ("soft-focus" effect). In its colloidal form, it could play a stabilizing and structuring role in gels or creams containing clays, making the texture more uniform, smooth, and pleasant to apply. It is also assumed, based on certain publications on silicon, that silica could support in the long term the skin’s firmness and elasticity by indirectly stimulating collagen synthesis, although these effects have been primarily demonstrated orally rather than topically.

The hypothesis of a synergy between clay and silica is therefore based on the idea of a multi-step action: first an immediate purification of the skin thanks to the absorbent/adsorbent effect of the clay, enhanced by the mattifying and texturizing action of the silica; then, potentially, a skin support effect through the contribution of silicon to tissue regeneration and the quality of the extracellular matrix. From a formulation standpoint, this combination would also allow for textures that are more pleasant, less drying, and more aesthetically pleasing than with clay alone, which can sometimes feel tight or crack when it dries on the skin.

Some cosmetic brands already capitalize on this combination in their products, which tends to confirm its practical value. However, it is important to emphasize that, to date, no comparative clinical study has shown that a formula combining clay and silica is more effective than a treatment containing only one of these two components.

This therefore represents a promising approach, founded on hypotheses derived from the individual properties of each ingredient, but it should be validated by targeted dermatological studies.

The relationship between silica and collagen synthesis is drawing increasing interest, although to date it has been investigated mainly through oral supplementation rather than topical application. Collagen is a structural protein essential for the firmness, elasticity, and cohesion of the skin. It is well established that its production declines with age, contributing to the appearance of wrinkles, loss of skin tone, and dehydration.

Silicon, a naturally occurring element in silica, is involved in the biosynthesis of collagen and glycosaminoglycans in connective tissues. Some studies have shown that organic silicon, when administered orally as silicates or monomethylsilanetriol (MMST), can stimulate collagen production and improve dermal density.

For example, a study published in American Journal of Clinical Nutrition highlighted a correlation between silicon intake and improved bone and skin health, suggesting that silicon may act as a cofactor in the enzymatic steps of collagen synthesis. Similarly, a study published in 2012 in Journal of Investigative Dermatology observed an improvement in hair strength and skin elasticity following silicon ingestion. However, these beneficial effects on collagen are mainly associated with oral supplementation.

When applied topically, no direct clinical study to date has demonstrated an increase in collagen synthesis attributable to the presence of silica in a formulation. The skin barrier strongly restricts the absorption of mineral silica, especially in its non-solubilized amorphous form, casting doubt on its direct biological efficacy in the dermis. Nevertheless, some hypotheses have been proposed regarding the indirect potential of topical silica to support skin structure. For example, by forming a thin film on the skin’s surface, it could temporarily improve texture, smooth fine lines, and reduce the visual perception of skin aging (soft-focus effect). Moreover, silica-enriched colloidal formulations could help hydrate and protect the skin’s surface, which contributes to maintaining an environment conducive to dermal regeneration, although this does not necessarily involve direct collagen stimulation.

While the role of silicon in collagen synthesis is substantiated by several scientific studies on oral supplementation, the use of silica in topical applications is based more on mechanical and sensory hypotheses than on direct biological evidence.

To date, no study has shown that applying silica to the skin stimulates collagen production in vivo.

This is therefore an intriguing avenue, with plausible biochemical foundations, but it requires dedicated clinical research to be confirmed in a cosmetic context.