Magnesium stearate
Encyclopedia
Magnesium stearate, also called octadecanoic acid, magnesium salt, is a white substance which is solid at room temperature. It has the chemical formula . It is a salt containing two equivalents of stearate (the anion of stearic acid
) and one magnesium
cation (Mg2+). Magnesium stearate melts at about 120 °C, is not soluble in water, and is generally considered safe for human consumption at levels below 2500 mg/kg per day. In 1979, FDA's Subcommittee on GRAS (generally recognized as safe) Substances (SCOGS) reported, "There is no evidence in the available information on ... magnesium stearate ... that demonstrates, or suggests reasonable grounds to suspect, a hazard to the public when they are used at levels that are now current and in the manner now practiced, or which might reasonably be expected in the future."
Magnesium stearate is often used as a diluent in the manufacture of medical tablets, capsules and powders. In this regard, the substance is also useful, because it has lubricating properties, preventing ingredients from sticking to manufacturing equipment during the compression of chemical powders into solid tablets; magnesium stearate is the most commonly used lubricant for tablets. Studies have shown that magnesium stearate may affect the release time of the active ingredients in tablets, etc., but not that it reduces the over-all bioavailability of those ingredients. As a food additive or pharmaceutical excipient, its E number
is E470b.
Magnesium stearate is also used to bind sugar in hard candies and is a common ingredient in baby formulas. In pure powder form, the substance can be a dust explosion
hazard, although this issue is effectively insignificant beyond the manufacturing plants using it.
Magnesium stearate is manufactured from both animal and vegetable oils. Some nutritional supplements specify that the magnesium stearate used is sourced from vegetables.
Magnesium stearate is a major component of "bathtub rings". When produced by soap and hard water, magnesium stearate and calcium stearate
both form a white solid insoluble in water, and are collectively known as "soap scum
".
Stearic acid
Stearic acid is the saturated fatty acid with an 18 carbon chain and has the IUPAC name octadecanoic acid. It is a waxy solid, and its chemical formula is CH316CO2H. Its name comes from the Greek word στέαρ "stéatos", which means tallow. The salts and esters of stearic acid are called stearates...
) and one magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
cation (Mg2+). Magnesium stearate melts at about 120 °C, is not soluble in water, and is generally considered safe for human consumption at levels below 2500 mg/kg per day. In 1979, FDA's Subcommittee on GRAS (generally recognized as safe) Substances (SCOGS) reported, "There is no evidence in the available information on ... magnesium stearate ... that demonstrates, or suggests reasonable grounds to suspect, a hazard to the public when they are used at levels that are now current and in the manner now practiced, or which might reasonably be expected in the future."
Magnesium stearate is often used as a diluent in the manufacture of medical tablets, capsules and powders. In this regard, the substance is also useful, because it has lubricating properties, preventing ingredients from sticking to manufacturing equipment during the compression of chemical powders into solid tablets; magnesium stearate is the most commonly used lubricant for tablets. Studies have shown that magnesium stearate may affect the release time of the active ingredients in tablets, etc., but not that it reduces the over-all bioavailability of those ingredients. As a food additive or pharmaceutical excipient, its E number
E number
E numbers are number codes for food additives that have been assessed for use within the European Union . They are commonly found on food labels throughout the European Union. Safety assessment and approval are the responsibility of the European Food Safety Authority...
is E470b.
Magnesium stearate is also used to bind sugar in hard candies and is a common ingredient in baby formulas. In pure powder form, the substance can be a dust explosion
Dust explosion
A dust explosion is the fast combustion of dust particles suspended in the air in an enclosed location. Coal dust explosions are a frequent hazard in underground coal mines, but dust explosions can occur where any powdered combustible material is present in an enclosed atmosphere.- Conditions for...
hazard, although this issue is effectively insignificant beyond the manufacturing plants using it.
Magnesium stearate is manufactured from both animal and vegetable oils. Some nutritional supplements specify that the magnesium stearate used is sourced from vegetables.
Magnesium stearate is a major component of "bathtub rings". When produced by soap and hard water, magnesium stearate and calcium stearate
Calcium stearate
Calcium stearate is carboxylate of calcium that is found in some lubricants and surfactants. It is a white waxy powder.-Production and occurrence:Calcium stearate is produced by heating stearic acid, a fatty acid, and calcium oxide:...
both form a white solid insoluble in water, and are collectively known as "soap scum
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...
".