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Natural clay from the earth and its minerals, imperative for survival of life on our planet, have been used for medicinal purposes for thousands of years. , and for some, the environmental and sustainability viewpoint that minerals will not harm the environment after disposal.
Clay minerals namely consist of silica, alumina, and/or magnesia, and sometimes varying degrees of iron, sodium, potassium, calcium, and water. Depending on the type of clay, as many as 75 trace minerals may be present.
Ochre
The first uses of ochre, or natural clay earth pigment, are thought to be by Homo erectus and Homo neanderthalensis who used ochre with water to soothe irritations, heal wounds, and clean skin. The theory is that they mimicked some animals who instinctively used clay/mud/minerals in this manner.
The first recorded use of medicinal clay is on Mesopotamian clay tablets, dating to about 2500 B.C. The ancient Egyptian physicians used clays as anti-inflammatory agents and antiseptics. Clay was also used as a preservative during mummification.
Throughout history, clay has been used for dermatologic purposes. Aristotle (384-322 BC) made one of the first references to deliberately eating clay, earth, or soil by humans for therapeutic and religious purposes. Later, Marco Polo described in his travels seeing Muslim pilgrims cure fevers by ingesting “pink earth.”
The ochres have also long been found in indigenous and aboriginal art, and in current day Namibia, the Himba tribe have used Otjize paste (bright red clay consisting of butterfat, red ochre, and sometimes herbs) for their characteristic hairstyles and makeup, as well as for skin protection and as a soap replacement. Otjize is sacred to the culture and ethnic identity, signifying the beauty of their hair and skin and a sense of oneness with their surroundings (the earth). There are also many instances of religious, folklore, or mythological references of creation of life or creation of humankind from clay.
Dermatologic uses
The most common uses of clay in dermatology are for treatment of acne and in spa or cosmeceutical preparations to purportedly draw out dirt, impurities, or toxins.
Clay minerals are most commonly formed from prolonged chemical weathering of silicate-bearing rocks. Clay can also be formed from hydrothermal or volcanic activity. Chemical weathering takes place mainly by acid hydrolysis resulting from low concentrations of carbonic acid, dissolved in rainwater or released by plant roots. Clays differ in composition and structure depending upon the source. Simplistically, clay is structured in two layers, organized in various shapes, with varying minerals and electrical charges. The electric charge of clay allows the adsorption of various minerals, water, heavy and radioactive metals, free radicals, and other potentially unwanted byproducts of metabolic activity. With antibacterial properties and adsorptive properties, clay is often used to dry out acne or oily skin and/or to improve the appearance of large pores.
Bentonite clay
Bentonite clay is one of the most common forms of clay used in topical skin products. Bentonite clay, formed after volcanic ash has weathered and aged in the presence of water, is named after a formation called Benton Shale in the western United States. Bentonite has a strong negative electromagnetic charge and when mixed with water it swells like a sponge and can absorb 40-50 times its weight.
There are several types of Bentonite clay, named from the dominant element found within: Sodium bentonite, calcium bentonite, aluminum bentonite, and potassium bentonite are the most common. Bentonite clay is most commonly found in off-white or green colors.
Kaolin and red clay
Typically white or nearly white to sometimes gray in color, kaolin clay is one of the other most common types of clay used in skin care. While the minerals of the kaolin group display a relatively small specific surface area, compared with those of other clay groups, they can still adsorb small molecules, proteins, bacteria, and viruses on the surface of their particles.
Red clay, also sometimes seen in skin care, takes on its color because of a higher content of iron oxides.
In a 2011 study, Valenti et al. evaluated the impact of daily application of clay and retinoic acid 0.025% on the skin of rats.After 7 days, skin where clay had been applied showed a significant increase in collagen fibers, compared with control skin, while areas where retinoic acid had been applied did not show a significant increase in collagen fibers, compared with control skin.2
A recently published study claims that pH and its interaction with the clay particle surface charge may neutralize and impact properties – including antibacterial properties – of clay and is more significant than previously thought.3 The authors emphasize the dangers of this possibility with unregulated marketing and unsubstantiated bioceutical claims of products that contain clay. Many clay-based skin care products on the market today include other ingredients such as acids (for example salicylic acid, lactic acid, and malic acid) that may potentially counteract this issue and help enhance the targeted efficacy of the product.
The types and characteristics of all types of clay go beyond the scope of this column, but as demonstrated throughout history, clay may have a role in medicinal and dermatologic care, the research of which is still ongoing and is important in our understanding of how this earthly compound can affect our bodies.
Dr. Wesley and Dr. Talakoub are cocontributors to this column. Dr. Wesley practices dermatology in Beverly Hills, Calif. Dr. Talakoub is in private practice in McLean, Va. This month’s column is by Dr. Wesley. Write to them at [email protected]. They had no relevant disclosures.
References
1: Moraes JDD et al. Int J Pharm. 2017 Dec 20;534(1-2):213-219. doi: 10.1016/j.ijpharm.2017.10.031.
2: Valenti DMZ et al. Clin Exp Dermatol. 2012 Mar;37(2):164-8. doi: 10.1111/j.1365-2230.2011.04216.x
3. Incledion A et al. Biomolecules. 2021 Jan 5;11(1):58. doi: 10.3390/biom11010058.
Natural clay from the earth and its minerals, imperative for survival of life on our planet, have been used for medicinal purposes for thousands of years. , and for some, the environmental and sustainability viewpoint that minerals will not harm the environment after disposal.
Clay minerals namely consist of silica, alumina, and/or magnesia, and sometimes varying degrees of iron, sodium, potassium, calcium, and water. Depending on the type of clay, as many as 75 trace minerals may be present.
Ochre
The first uses of ochre, or natural clay earth pigment, are thought to be by Homo erectus and Homo neanderthalensis who used ochre with water to soothe irritations, heal wounds, and clean skin. The theory is that they mimicked some animals who instinctively used clay/mud/minerals in this manner.
The first recorded use of medicinal clay is on Mesopotamian clay tablets, dating to about 2500 B.C. The ancient Egyptian physicians used clays as anti-inflammatory agents and antiseptics. Clay was also used as a preservative during mummification.
Throughout history, clay has been used for dermatologic purposes. Aristotle (384-322 BC) made one of the first references to deliberately eating clay, earth, or soil by humans for therapeutic and religious purposes. Later, Marco Polo described in his travels seeing Muslim pilgrims cure fevers by ingesting “pink earth.”
The ochres have also long been found in indigenous and aboriginal art, and in current day Namibia, the Himba tribe have used Otjize paste (bright red clay consisting of butterfat, red ochre, and sometimes herbs) for their characteristic hairstyles and makeup, as well as for skin protection and as a soap replacement. Otjize is sacred to the culture and ethnic identity, signifying the beauty of their hair and skin and a sense of oneness with their surroundings (the earth). There are also many instances of religious, folklore, or mythological references of creation of life or creation of humankind from clay.
Dermatologic uses
The most common uses of clay in dermatology are for treatment of acne and in spa or cosmeceutical preparations to purportedly draw out dirt, impurities, or toxins.
Clay minerals are most commonly formed from prolonged chemical weathering of silicate-bearing rocks. Clay can also be formed from hydrothermal or volcanic activity. Chemical weathering takes place mainly by acid hydrolysis resulting from low concentrations of carbonic acid, dissolved in rainwater or released by plant roots. Clays differ in composition and structure depending upon the source. Simplistically, clay is structured in two layers, organized in various shapes, with varying minerals and electrical charges. The electric charge of clay allows the adsorption of various minerals, water, heavy and radioactive metals, free radicals, and other potentially unwanted byproducts of metabolic activity. With antibacterial properties and adsorptive properties, clay is often used to dry out acne or oily skin and/or to improve the appearance of large pores.
Bentonite clay
Bentonite clay is one of the most common forms of clay used in topical skin products. Bentonite clay, formed after volcanic ash has weathered and aged in the presence of water, is named after a formation called Benton Shale in the western United States. Bentonite has a strong negative electromagnetic charge and when mixed with water it swells like a sponge and can absorb 40-50 times its weight.
There are several types of Bentonite clay, named from the dominant element found within: Sodium bentonite, calcium bentonite, aluminum bentonite, and potassium bentonite are the most common. Bentonite clay is most commonly found in off-white or green colors.
Kaolin and red clay
Typically white or nearly white to sometimes gray in color, kaolin clay is one of the other most common types of clay used in skin care. While the minerals of the kaolin group display a relatively small specific surface area, compared with those of other clay groups, they can still adsorb small molecules, proteins, bacteria, and viruses on the surface of their particles.
Red clay, also sometimes seen in skin care, takes on its color because of a higher content of iron oxides.
In a 2011 study, Valenti et al. evaluated the impact of daily application of clay and retinoic acid 0.025% on the skin of rats.After 7 days, skin where clay had been applied showed a significant increase in collagen fibers, compared with control skin, while areas where retinoic acid had been applied did not show a significant increase in collagen fibers, compared with control skin.2
A recently published study claims that pH and its interaction with the clay particle surface charge may neutralize and impact properties – including antibacterial properties – of clay and is more significant than previously thought.3 The authors emphasize the dangers of this possibility with unregulated marketing and unsubstantiated bioceutical claims of products that contain clay. Many clay-based skin care products on the market today include other ingredients such as acids (for example salicylic acid, lactic acid, and malic acid) that may potentially counteract this issue and help enhance the targeted efficacy of the product.
The types and characteristics of all types of clay go beyond the scope of this column, but as demonstrated throughout history, clay may have a role in medicinal and dermatologic care, the research of which is still ongoing and is important in our understanding of how this earthly compound can affect our bodies.
Dr. Wesley and Dr. Talakoub are cocontributors to this column. Dr. Wesley practices dermatology in Beverly Hills, Calif. Dr. Talakoub is in private practice in McLean, Va. This month’s column is by Dr. Wesley. Write to them at [email protected]. They had no relevant disclosures.
References
1: Moraes JDD et al. Int J Pharm. 2017 Dec 20;534(1-2):213-219. doi: 10.1016/j.ijpharm.2017.10.031.
2: Valenti DMZ et al. Clin Exp Dermatol. 2012 Mar;37(2):164-8. doi: 10.1111/j.1365-2230.2011.04216.x
3. Incledion A et al. Biomolecules. 2021 Jan 5;11(1):58. doi: 10.3390/biom11010058.
Natural clay from the earth and its minerals, imperative for survival of life on our planet, have been used for medicinal purposes for thousands of years. , and for some, the environmental and sustainability viewpoint that minerals will not harm the environment after disposal.
Clay minerals namely consist of silica, alumina, and/or magnesia, and sometimes varying degrees of iron, sodium, potassium, calcium, and water. Depending on the type of clay, as many as 75 trace minerals may be present.
Ochre
The first uses of ochre, or natural clay earth pigment, are thought to be by Homo erectus and Homo neanderthalensis who used ochre with water to soothe irritations, heal wounds, and clean skin. The theory is that they mimicked some animals who instinctively used clay/mud/minerals in this manner.
The first recorded use of medicinal clay is on Mesopotamian clay tablets, dating to about 2500 B.C. The ancient Egyptian physicians used clays as anti-inflammatory agents and antiseptics. Clay was also used as a preservative during mummification.
Throughout history, clay has been used for dermatologic purposes. Aristotle (384-322 BC) made one of the first references to deliberately eating clay, earth, or soil by humans for therapeutic and religious purposes. Later, Marco Polo described in his travels seeing Muslim pilgrims cure fevers by ingesting “pink earth.”
The ochres have also long been found in indigenous and aboriginal art, and in current day Namibia, the Himba tribe have used Otjize paste (bright red clay consisting of butterfat, red ochre, and sometimes herbs) for their characteristic hairstyles and makeup, as well as for skin protection and as a soap replacement. Otjize is sacred to the culture and ethnic identity, signifying the beauty of their hair and skin and a sense of oneness with their surroundings (the earth). There are also many instances of religious, folklore, or mythological references of creation of life or creation of humankind from clay.
Dermatologic uses
The most common uses of clay in dermatology are for treatment of acne and in spa or cosmeceutical preparations to purportedly draw out dirt, impurities, or toxins.
Clay minerals are most commonly formed from prolonged chemical weathering of silicate-bearing rocks. Clay can also be formed from hydrothermal or volcanic activity. Chemical weathering takes place mainly by acid hydrolysis resulting from low concentrations of carbonic acid, dissolved in rainwater or released by plant roots. Clays differ in composition and structure depending upon the source. Simplistically, clay is structured in two layers, organized in various shapes, with varying minerals and electrical charges. The electric charge of clay allows the adsorption of various minerals, water, heavy and radioactive metals, free radicals, and other potentially unwanted byproducts of metabolic activity. With antibacterial properties and adsorptive properties, clay is often used to dry out acne or oily skin and/or to improve the appearance of large pores.
Bentonite clay
Bentonite clay is one of the most common forms of clay used in topical skin products. Bentonite clay, formed after volcanic ash has weathered and aged in the presence of water, is named after a formation called Benton Shale in the western United States. Bentonite has a strong negative electromagnetic charge and when mixed with water it swells like a sponge and can absorb 40-50 times its weight.
There are several types of Bentonite clay, named from the dominant element found within: Sodium bentonite, calcium bentonite, aluminum bentonite, and potassium bentonite are the most common. Bentonite clay is most commonly found in off-white or green colors.
Kaolin and red clay
Typically white or nearly white to sometimes gray in color, kaolin clay is one of the other most common types of clay used in skin care. While the minerals of the kaolin group display a relatively small specific surface area, compared with those of other clay groups, they can still adsorb small molecules, proteins, bacteria, and viruses on the surface of their particles.
Red clay, also sometimes seen in skin care, takes on its color because of a higher content of iron oxides.
In a 2011 study, Valenti et al. evaluated the impact of daily application of clay and retinoic acid 0.025% on the skin of rats.After 7 days, skin where clay had been applied showed a significant increase in collagen fibers, compared with control skin, while areas where retinoic acid had been applied did not show a significant increase in collagen fibers, compared with control skin.2
A recently published study claims that pH and its interaction with the clay particle surface charge may neutralize and impact properties – including antibacterial properties – of clay and is more significant than previously thought.3 The authors emphasize the dangers of this possibility with unregulated marketing and unsubstantiated bioceutical claims of products that contain clay. Many clay-based skin care products on the market today include other ingredients such as acids (for example salicylic acid, lactic acid, and malic acid) that may potentially counteract this issue and help enhance the targeted efficacy of the product.
The types and characteristics of all types of clay go beyond the scope of this column, but as demonstrated throughout history, clay may have a role in medicinal and dermatologic care, the research of which is still ongoing and is important in our understanding of how this earthly compound can affect our bodies.
Dr. Wesley and Dr. Talakoub are cocontributors to this column. Dr. Wesley practices dermatology in Beverly Hills, Calif. Dr. Talakoub is in private practice in McLean, Va. This month’s column is by Dr. Wesley. Write to them at [email protected]. They had no relevant disclosures.
References
1: Moraes JDD et al. Int J Pharm. 2017 Dec 20;534(1-2):213-219. doi: 10.1016/j.ijpharm.2017.10.031.
2: Valenti DMZ et al. Clin Exp Dermatol. 2012 Mar;37(2):164-8. doi: 10.1111/j.1365-2230.2011.04216.x
3. Incledion A et al. Biomolecules. 2021 Jan 5;11(1):58. doi: 10.3390/biom11010058.
