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Magnesium Aluminum Silicate (MAS)

Magnesium Aluminum Silicate (MAS)

Fast Facts       


Type of Ingredient:  Magnesium Aluminum Silicate (MAS) is a viscosity-increasing agent, absorbent, anticaking agent, opacifying agent, and emulsion stabilizer.


Main Benefits: Used as a transformer and binder in many cosmetic products, especially in products with high pH levels. Used as a thickening agent. 


Who Should Use It: generally, it is used by people who use Haircare products (shampoos, conditioners & styling products), shower gels, creams, lotions, make-up, shaving creams, and deodorants.

Ideal For These Concerns: Magnesium Aluminum Silicate is used as a powder in cosmetic products. It can absorb liquids, prevents powder products from becoming clumpy and helps other ingredients apply more smoothly.

How Often Can You Use It: You can use it daily 

Works well with:  When used with Alcuronium, the remedial efficacy of Alcuronium can be enhanced when used in combination with Magnesium Aluminum Silicate.


What is Magnesium Aluminum Silicate? 

Magnesium aluminum silicate is a naturally occurring mineral obtained from silicate ores of smectite clay. It is then purified to a powdery, dry-feeling, white solid state powder that is highly used in cosmetics and pharmaceutical treatments. Magnesium aluminum silicate has the ability to be easily absorbed into the skin. Magnesium aluminum silicate is often used in products with a high pH level, such as depilatory, waving, and hair relaxer products.


The Benefits of Magnesium Aluminum Silicate

The main use of magnesium aluminum silicate is as a viscosity-increasing agent. The term viscosity represents the “thickness”, for example, honey has a higher viscosity than water. Therefore, as a viscosity-increasing agent, magnesium aluminum silicate can thicken formulas to make a product thicker and easier to spread. This feature is especially useful in deodorants, shaving creams, and thick lotions. Moreover, magnesium aluminum silicate acts in combination with other thickeners such as xanthan gum.


Magnesium aluminum silicate is listed as an absorbent because of its ability to absorb or soak up liquids. Due to this property, magnesium aluminum silicate can also be used as an anticaking agent. By absorbing liquids, it prevents powdery products from clumping together and helps other ingredients to apply more softly on the skin. Besides, as an opacifying agent, magnesium aluminum silicate can be added to clear or transparent cosmetic formulas to make them more resistance to light.


Finally, magnesium aluminum silicate is used as an emulsion stabilizer. An emulsion is a mixture of two or more immiscible liquids, for instance, water and oil. Mixing water and oil creates a dispersion of oil droplets in water (and vice versa). However, these two phases can separate if the product is left to settle. The smectite colloidal structure of magnesium aluminum silicate effectively keeps the internal phase droplets suspended and separated and reduces the tendency of emulsions to thin out and break at elevated temperatures. Magnesium aluminum silicate can stabilize both oil-in-water and water-in-oil emulsions at low concentrations.




The safety of magnesium aluminum silicate has been evaluated by the Cosmetic Ingredient Review (CIR) Expert Panel. Because of its solid particle form, some studies have shown that this ingredient could be irritating when in contact with the eyes. But after topical applications of magnesium aluminum silicate to human skin daily for one week showed no evidence of that. It was not found to be irritating or sensitizing to the skin. Since magnesium aluminum silicate is made up of large particles, this ingredient cannot be absorbed by the skin. Therefore, it cannot cause any reactions because it cannot react with cells of the immune system. After evaluating the scientific data, the CIR Expert Panel concluded that magnesium aluminum silicate was safe as used in cosmetics and personal care products.  According to EWG’s Skin Deep Cosmetic Database, magnesium aluminum silicate is considered to be safe as used in cosmetics and personal care products. It is rated as a 1 on a scale of 1 to 10, with 1 being the lowest risk to health and 10 being the highest.



Elmore AR: Final report on the safety assessment of aluminum silicate, calcium silicate, magnesium aluminum silicate, magnesium silicate, magnesium trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite, bentonite, Fuller's earth, hectorite, kaolin, lithium magnesium silicate, lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and zeolite. Int J Toxicol. 2003;22 Suppl 1:37-102. [PubMed:12851164]

Making Cosmetics “Magnesium Aluminum Silicate”, Cosmetics Info “Magnesium Aluminum Silicate”, Int J Toxicol. 2003;22 Suppl 1:37-102.