Before nanoclay became a topic of serious industrial interest in the 1990s, it was already present in cosmetics and personal care products. Bentonite masks, kaolin cleansers, and smectite-thickened emulsions have been commercial products for most of the twentieth century. What has changed is the level of understanding about why these clays work, how to optimise their use, and what the regulatory environment requires formulators to demonstrate about safety.
This article covers the principal applications of nanoclay in personal care — rheology modification, active ingredient delivery, skin interaction — and addresses the safety question that is increasingly important for formulators in the EU and elsewhere.
Why nanoclay belongs in cosmetics formulations
The properties that make nanoclay useful in industrial formulations — high surface area, ion exchange capacity, colloidal stability, thixotropic gel formation — translate directly into cosmetic performance attributes.
A thixotropic foundation or BB cream applies easily under a brush or sponge (low viscosity during shear) but holds its position and does not slide on skin (viscosity recovery). A mascara that does not drip during application and does not smear after relies on the same gel network. A sunscreen that does not run into eyes requires a yield stress that low-viscosity emulsions do not naturally possess.
Nanoclay provides all of these without the sensory penalties associated with some polymer thickeners — the stickiness or tackiness that certain carbomers or cellulosics can introduce.
Clay types used in personal care
Laponite (synthetic hectorite, BYK Additives) is the premium choice for transparent and translucent formulations. Its very small platelet size (20–30 nm diameter vs. 200–500 nm for natural montmorillonite) produces gels that are optically clear, which is essential in serums, eye gels, and clear cosmetic formulations. Laponite gels are also electrostatically stable across a wide pH range and are compatible with many active ingredients. The cost premium over natural clays is significant, but for high-value personal care products the performance justifies it.
Hectorite (natural, sourced from deposits in California and elsewhere) provides similar thixotropic performance to laponite at lower cost, with slightly lower optical clarity. It is used in foundations, lotions, and colour cosmetics where transparency is not required.
Montmorillonite / bentonite is the highest-volume clay in cosmetics by tonnage, used in face masks, body powders, and as a cheap thickener in rinse-off products. It imparts the characteristic “clay mask” sensation of tightening and drying as the product sets on skin, which is perceived as cleansing. Its high adsorption capacity removes sebum, surface contaminants, and skin debris — the mechanism behind its use in clarifying and detoxifying products.
Kaolin is technically a non-swelling clay (kaolinite, not smectite) and does not form the card-house network structures that give smectites their thixotropic properties. It functions primarily as a bulking agent, oil absorber, and slip modifier in powders, pressed products, and loose foundations. It is not a nanoclay in the strict structural sense but is often grouped with clays in cosmetic literature.
Thickening and stabilisation
The primary functional use of nanoclay in cosmetics is rheology modification and emulsion stabilisation. Both rely on the same gel network mechanism described for industrial coatings, adapted to the aqueous continuous phase of a cosmetic formulation.
In oil-in-water emulsions (most lotions, serums, and creams), dispersed nanoclay builds a gel network in the continuous water phase that physically stabilises droplets against coalescence and creaming. This Pickering-type stabilisation — where particles rather than surfactants stabilise the emulsion interface — is increasingly attractive to formulators seeking to reduce surfactant use or achieve clean-label positioning, since clay is a natural ingredient and is Cosmos/Ecocert compliant when properly sourced.
The gel network provides yield stress, so droplets cannot creep through the aqueous phase under gravity. A well-formulated nanoclay-stabilised emulsion can achieve extraordinary physical stability — years of shelf life without phase separation — with minimal or no conventional emulsifier.
Active ingredient delivery
Nanoclay’s high surface area and ion exchange capacity make it an effective carrier for active ingredients, in two distinct ways.
Adsorption-based delivery: Positively charged active molecules (certain antimicrobial actives, amino acid derivatives, some peptides) can be adsorbed onto the negatively charged clay surface by electrostatic interaction and released gradually as the formulation contacts skin. This prolongs the surface residence time of the active and can enhance skin contact relative to an unbound active that simply washes off or diffuses away.
Intercalation-based delivery: Small organic molecules can be inserted into the clay interlayer gallery, protected from environmental degradation, and released when the formulation is applied to skin. This has been demonstrated with vitamins (retinol, ascorbic acid), UV filters, and fragrance components. The interlayer environment protects labile molecules from oxidation and hydrolysis during product shelf life, then releases them on application when the clay disperses and gallery access increases.
Both mechanisms have been used in published formulation research and in commercial products, though formulation-specific optimisation is required for each active-clay pairing.
Skin interaction and the clay mask effect
The sensory effects associated with clay-based face masks — tightening, drying, cooling — are physical rather than chemical. As the mask dries after application, water evaporates and the clay contracts. The mechanical tension this creates on skin is perceived as tightening and attributed to “pore-minimising” effects, though the effect is temporary (it disappears when the mask is removed and skin rehydrates).
More substantive is the sebum and contamination adsorption that occurs during mask contact time. Clay surfaces have high affinity for lipids and polar organic molecules. During the 10–20 minutes a clay mask sits on skin, it adsorbs sebum, surface debris, and some surface microorganisms from the skin surface. This does contribute to a genuine (if temporary) reduction in surface oiliness.
Safety and regulatory status
Nanoclay safety in cosmetics has been evaluated by the Scientific Committee on Consumer Safety (SCCS) in the EU, and natural montmorillonite and hectorite used as cosmetic ingredients are on the EU’s permitted ingredient list. The key regulatory concern — as with any nanomaterial — is whether the ingredient in its formulated form can penetrate intact skin and reach systemic circulation.
The evidence strongly indicates that nanoclay platelets do not penetrate intact skin. The platelet dimensions (lateral size of hundreds of nanometres, with 1 nm thickness) are too large for transdermal transport through stratum corneum, and the hydrophilic nature of the clay surface makes partitioning into lipid-rich skin layers energetically unfavourable. Multiple skin penetration studies support this conclusion.
The EU Cosmetics Regulation requires nanomaterials to be notified and assessed, and “clay” materials are currently treated under the general mineral ingredient framework rather than as novel nanomaterials — though this is an area of ongoing regulatory development. Formulators working in the EU should monitor SCCS opinions and the Cosmetics Ingredient Database (CosIng) for updated guidance.
The US FDA treats cosmetic-grade clay as generally recognised as safe within established use conditions. No post-market safety signals from cosmetic nanoclay use have emerged in the published literature or regulatory surveillance.
Lawrence Fine is CEO of AGCP Farmacêuticos, a Lisbon-based nanotechnology company with research programs in nanoclay formulation for pharmaceutical and topical applications.