Is the use of clay minerals in cosmetics production an old, outdated technology?

Natural, modified, or synthetic clay minerals are among the most commonly used ingredients in the cosmetics manufacturing industry. Reading the latest scientific publications, we notice an increasing interest among scientists in using these minerals as carrier systems for active substances.

In cosmetics, clay has been used both as an active ingredient and as an auxiliary substance whose main purpose is to improve the composition of the cosmetic product and provide additional properties, such as increasing the product's viscosity [1, 2]. Additionally, clay can be used as an emulsifier [3], stabilizer for various suspensions [4], and moisturizer. Various clay minerals are used as binders in the creation of toothpaste or as SPF factors because they can reflect UV radiation and act as enhancers for other UV filters [5]. Of course, clay minerals are also used in various powders, deodorants, dry shampoos, and other cosmetic product formulations. Moreover, various clay compounds are often used in dermo-cosmetic products intended for local use and exhibit properties that stop skin aging, promote wound healing, have anti-inflammatory and irritation-reducing effects, are easily removable, and actively work against acne [6, 7].

Let's talk about new methods of application of clay minerals. One example is the formation of nanotubes from the kaolin group clay, which has the same chemical composition as kaolinite and is called halloysite. This clay forms nanotubes with a length of 0.2-1.5 µm, and an inner and outer diameter of 10-30 nm and 40-70 nm respectively. The inner surface of the nanotubes is made of aluminum hydroxide with a positive charge, while the outer surface is made of silicon dioxide with a negative charge. The composition and structure of this clay are biologically compatible and easily adaptable to the cosmetics industry due to its low cost.

One possible way to apply this clay is by immobilizing (inserting) various active substances into the nanotubes. One such ingredient is vitamin A, also known as retinol. At low concentrations in a product, retinol has softening properties for the skin, as well as improves collagen and elastin synthesis, providing moisturization and beautification. At higher concentrations, retinol has keratolytic activity, reducing the stratum corneum (promoting cell renewal), wrinkles, acne scars, and has depigmenting properties. Therefore, retinol is often used as an active ingredient in many skincare products to reduce wrinkles, hyperpigmentation, acne, psoriasis, and other skin problems. However, one of the biggest drawbacks of retinol as an active ingredient is its low solubility in water and sensitivity to light and oxygen. One solution is the retinol-halloysite system (retinol-halloysite composite), which can provide more stable final product formulations and efficacy. Clay minerals can improve the solubility of this substance in water and stabilize it (protecting it from sunlight).

Among the ten most commonly used antioxidants in recent years is niacinamide, which can also be used in the halloysite system. Niacinamide, also known as nicotinamide, is a form of vitamin B3 and is a precursor of nicotinamide adenine dinucleotide (NAD) in human cells. Due to its antioxidant effect, this ingredient can be used in products that prevent skin aging, but it also has anti-inflammatory properties and reduces acne and hyperpigmentation. Therefore, it is a highly useful active ingredient in combating skin problems such as rosacea, acne, and signs of aging.

In current skincare cosmetics, one of the frequently used active ingredients is glycolic acid, which is the smallest alpha hydroxy acid. This active ingredient penetrates the deepest layers of the skin and acts as a surface chemical exfoliant, commonly used in combination with retinoids as one of the most commonly used skin peels. Glycolic acid is widely used to treat moderate sun damage, actinic damage, acne, seborrheic skin, rosacea, and pigmentary disorders. Therefore, niacinamide-halloysite and glycolic acid-halloysite composites would provide significant advantages in the cosmetics industry, where halloysite clay would act not only as an auxiliary substance but also as a carrier and protective material that would prevent the breakdown of active ingredients. Retinol, niacinamide, and glycolic acid are molecules that, when used in combination with halloysite clay minerals, could create innovative and new skincare product formulas. Theoretical calculations and molecular modeling methods have shown that such formulas would exhibit greater activity and stability.

Therefore, the use of clay minerals in cosmetics product formulations is still an area that attracts significant attention from scientists.

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