Why use clay in your skincare routine?

How is clay formed?

The result of a long natural process, clay is the result of the gradual weathering, under the influence of climatic phenomena, of rocks containing silicon. Over the years, through erosion and sedimentation, the minerals in the original rock break down, are transported by water and wind, and eventually transform into new clay minerals. This slow metamorphosis takes place differently depending on the parent rock, the original soil and the local climate, which is why there are different varieties of clay (1).

What is its composition?

At a microscopic level, clay appears as a stack of thin layers, much like a mineral mille-feuille. These layers are composed of silicon and aluminium, and sometimes even iron or magnesium, depending on the type of clay. This layered structure enables the clay to retain water and capture impurities, as well as any other substances present on its surface – a quality that is highly sought after in cosmetics (2).

What are the different types of clay?

Clays belong to the phyllosilicate family. There are several types of clay, which can be classified according to their colour:

• Green clay: the best known, it comes in two forms, Illite and Montmorillonite. It is rich in silica and magnesium.

• White clay : also known as kaolin, it is rich in silica and has a low concentration of mineral salts. Its white colour comes from its high alumina content.

• Red clay: it contains a lot of iron oxide, which gives it its colour.

• Yellow clay: less well known, it is particularly rich in magnesium and iron.

Absorption of sebum and impurities

Clay is made up of very fine particles arranged in layers. This structure creates a large surface area, as well as being particularly porous. When a clay mask is applied to the skin, it triggers a sort of ‘drawing’ effect that captures excess sebum, pollution particles and residues present on the skin’s surface, binding them to the clay (3). For this reason, clay is particularly well suited to combination to oily skin prone to shine.

Reduction in blemishes

A study conducted by Meier and his team in 2012 assessed the effectiveness of clay masks combined with jojoba oil on around 100 people prone to mild acne and blemishes. There was an average reduction of 54 per cent in the total number of skin lesions, such as papules, pustules, cysts and comedones, was observed after 6 weeks of applying the mask 2 to 3 times a week (4).

Purifies the skin

Depending on their mineral composition, certain clays have a negative surface charge and cation exchange capacity, which enable them to bind various ions and molecules to their surface. When the clay is applied as a face mask, it attracts oppositely charged positive ions and can exchange them upon contact with the skin. As a result, it helps to rid the skin’s surface of excess sebum and certain impurities.

Combination to oily skin

Clay, and green clay in particular, is suitable for oily and combination skin. Its high absorbency enables it to capture sebum and impurities on the skin’s surface, making it an ideal treatment for the excess sebum characteristic of this skin type (3). Clay therefore helps to purify and mattify oily or combination skin.

Blemish-prone and acne-prone skin

Thanks to its absorbent and purifying properties, clay is often recommended for skin prone to blemishes or with an acne-prone tendency. On the one hand, it helps to absorb excess sebum—which causes pores to become blocked, creating an environment conducive to the development of blemishes—by binding to it. Furthermore, it purifies the skin and helps to remove excess sebum and certain impurities.

Can people with sensitive skin use clay?

Clay may be suitable for sensitive skin, but it all depends on how it is used. White clay (kaolin), yellow clay, red clay and pink clay (a mixture of white and red clay) are generally well tolerated by sensitive and delicate skin. Green clay should be used with greater caution due to its highly absorbent properties. It is more suitable for combination to oily skin or skin prone to blemishes. However, the new Aroma-Zone green clay mask stick has been specifically designed for sensitive skin.

To avoid any tightness, it is important to remove the clay mask with lukewarm water before it dries completely on the skin, and to limit its use to a maximum of once or twice a week.

Regularly applying a clay mask to your face can help:

• Clearer skin: by helping to reduce blemishes

• A matt finish: by helping to absorb excess sebum, which is responsible for shine

• Purified skin : by attracting and trapping impurities accumulated on the skin’s surface 

• Smoother skin: by removing dead skin cells and minimising blemishes that affect skin texture

• A refreshing sensation: by leaving the skin feeling fresh after rinsing.

Before using a clay mask, it is advisable to carry out a patch test on the inside of your elbow before applying it to your face. Wait 48 hours to check that there are no reactions. As clay absorbs impurities, you should not reuse clay that has already been used. When preparing homemade clay masks, avoid direct contact with metal during preparation. It is best to use a glass bowl and a wooden spoon.

Due to their high absorbency, clays can accumulate potentially undesirable trace elements. This is why, for use on the skin, it is particularly important to choose clays that have undergone purity testing (3).

With a dual background in literature and marketing, Hélène Durand uses her writing to explore topics that are meaningful to her: natural beauty, well-being, and a healthy lifestyle. Through her articles, she aims to share a supportive perspective and practical advice.