Magnesium stearate is a salt of magnesium and stearic acid, commonly used as an anticaking agent in foods. It is also used in cosmetics and pharmaceuticals as a lubricant and flow aid.

In food products, magnesium stearate may be added as an anticaking agent to flour or sugar. Magnesium stearate is also used as a lubricant to prevent the food chemical supplier formation of gas bubbles in carbonated soft drinks and beer. It is often used in conjunction with other anticaking agents such as silicon dioxide (E551) and calcium silicate (E551b).

What is magnesium stearate used for?

Magnesium stearate is an anti-caking agent, used in foods and cosmetics to prevent ingredients from sticking together. It also increases the flow properties of powders by reducing their particle size. Magnesium stearate is a food additive that helps keep products from clumping together and improves flow properties. It is also used in cosmetics as an emollient, lubricant, and thickening agent.

In foods, magnesium stearate acts as an anti-caking agent — it helps prevent ingredients from sticking together before they are added to a formula.

In cosmetics, magnesium stearate is used as an emollient (a substance that softens or soothes the skin). It also functions as a lubricant (a substance that reduces friction between moving parts) and a thickening agent (a substance that increases viscosity).

Magnesium stearate is also used as a tablet binder in pharmaceuticals, especially for prolonged-release formulations.

Magnesium stearate is used in a wide variety of consumer goods, including baked goods, chewing gum, and hard candy. It can also be found in products such as custom chemical supplier cosmetics (e.g., moisturizers), toothpaste, hair conditioners, and shaving creams. Magnesium stearate is a white powder or granule with a neutral odor and taste. It dissolves easily in water and alcohol but is insoluble in fats and oils.

What is vegetable magnesium stearate made from?

Vegetable magnesium stearate is made from vegetable oils such as palm oil, coconut oil, and soya bean oil. The term ‘vegetable’ refers to the source of the oil and not the food it is used to make.

The exact manufacturing process varies from company to company but generally involves heating the oil in a pressurized vessel to create a paste. The paste is then dried into a powder and ground up into smaller pieces.

Some manufacturers use synthetic chemicals during this process, but others are able to produce the powder using only natural ingredients like plants and oils.

What is magnesium stearate made of?

Magnesium stearate is made from mixed fatty acids extracted from palm oil and palm kernel oil, which are natural ingredients found in plants. The mixed fatty acids are then dissolved into water to form an emulsion or suspension; this process creates the magnesium stearate crystals that are then filtered out of the solution using centrifuges or filters before being dried at high temperatures to make them into fine powders.

How is magnesium stearate made?

Due to the weak nature of stearic acid, it cannot be directly converted into magnesium stearate by reacting with magnesium sulfate.

Stearic acid and metal salt characteristics combined. In addition to its lubricity, stearic acid is also hydrophobic.

In the presence of strong acids, it will decompose into magnesium salt and stearic acid.

The surface area of the product is very large, it is highly adsorbent and hygroscopic, it feels slippery when in contact with the skin, and it sticks easily to the skin.

Appearance

Two nonpolar fatty acid molecules can be bound by divalent Mg2+, whereas only one fatty acid can be bound by monovalent Na+ and K+.

Mg2+ is insoluble in water due to two fatty acid molecules protecting it from water molecules.

Structure

A magnesium cation and two stearate anions compose this salt. The molecule structure consists of 36 carbon atoms in total.

What’s the application of magnesium stearate?

In cosmetic products, pharmaceutical tablets & capsules, food supplements, and plastic products, magnesium stearate serves a multitude of functions.

Food

This food-grade product can be used as a flow agent and anti-caking agent, as a lubricant, and as a magnesium supplement in dietary supplements.

In the production of vitamins or multivitamins, magnesium stearate helps to bind with other ingredients to prevent them from sticking or clumping to machine surfaces.

Powdered cosmetics (such as talcum powder makeup) are often enriched with magnesium stearate for improved adhesion and smoothness on the skin surface.

As well as thickening and emollient properties, magnesium stearate can also be used as a cosmetic additive and a personal care ingredient.

Aluminum stearate, zinc stearate, and magnesium stearate are commonly used adhesives. After adding the metal salts of stearic acid, the powdered cosmetics are not permeable to water because they are enclosed by other powder particles.

As aluminum stearate is rough and calcium stearate lacks smoothness, magnesium and zinc stearate are commonly used in this field.

Plastics

Is magnesium stearate safe?

When used as a food additive, it almost never causes side effects. The FDA generally recognizes magnesium stearate as a safe direct human food ingredient (GRAS).

No limitations other than current good manufacturing practice apply to its use as a lubricant, nutrient supplement, and processing aid in food.

In 2018, the European Food Safety Authority re-evaluated the safety of magnesium salts of fatty acids (E470b), sodium salts of fatty acids, potassium salts of fatty acids, and calcium salts of fatty acids as food additives.

According to EFSA, magnesium salts of fatty acids are not a safety concern due to their reported uses and doses, and there is no need to establish a numerical acceptable daily intake (ADI).

Anticaking agents, binders, and emulsifiers are the components of this additive according to JECFA. ADIs “not specific” were established in 2015.