Magnesium sulfate is a natural ingredient that is used in cosmetics and personal care products as an exfoliant, bulking agent, and anti-inflammatory agent.
Magnesium sulfate is an inorganic salt that can be found in the mineral epsomite, which is commonly called Epsom salt. Epsomite was first described in 1806 for an occurrence near Epsom, Surrey, England, after which it was named. It forms as encrustations on limestone cavern walls and mine timbers and walls. Epsom salt has been traditionally used as a component of bath salts, functioning as a healing agent and pain reliever. Epsom salt can also be taken orally as a laxative to relieve occasional constipation and to treat low levels of magnesium.
Magnesium sulfate is typically manufactured by mining of natural minerals or by reaction of available ore or inorganic oxides, hydroxides, or carbonates, with sulfuric acid. These methods produce hydrated inorganic sulfates. To produce the anhydrous salts, an additional step of dehydration (i.e., by heating and reduced pressure) must occur. Magnesium sulfate is soluble in water and sparingly soluble in alcohol.
In cosmetics and personal care products, magnesium sulfate is used at concentrations up to 11% and 25% in leave-on and rinse-off products, respectively. It functions as a natural exfoliant, bulking agent, and anti-inflammatory agent.
Magnesium sulfate exists in the form of small, crystalline particles, which enables this ingredient to function as a gentle abrasive. Products that contain magnesium sulfate as an abrasive will help to exfoliate the top layers of skin, removing dead skin cells, makeup, excess oil, dirt, and other impurities that may have accumulated during the day. Getting rid of dead skin cells that build up on the skin’s surface is crucial in order to maintain clear skin. This is because the accumulation of extra dead cells can clog pores, eventually turning into undesirable acne or other dermal-related conditions. Furthermore, exfoliating becomes even more important as we age since the skin’s natural cycle of shedding dead cells slows down.
Since magnesium sulfate is a non-reactive, solid ingredient, it can also be used as a bulking agent in cosmetic formulations. Bulking agents are used to dilute other solids or to increase the volume of a product.
Magnesium sulfate as Epsom salt is typically added to warm water like a bath in order to relieve pain and inflammation. In water, magnesium sulfate breaks down into magnesium and sulfate ions. Both magnesium and sulfate are readily absorbed through the skin and into the bloodstream. Replenishing magnesium levels has several health benefits, including reducing inflammation, promoting relaxation, relieving muscle aches and pains, healing small cuts and scrapes, increasing energy, and drawing toxins from the body. Soaking feet in warm water and magnesium sulfate can help to reduce inflammation from gout, eliminate odor, and help treat infection.
The anti-inflammatory properties of magnesium sulfate may also help to treat acne. Blemishes form due to excess sebum and bacteria clogging pores, followed by inflammation and swelling. Applying an anti-inflammatory agent like magnesium sulfate can soothe inflamed blemishes, which can help them heal faster. The value of using magnesium sulfate for acne has not been scientifically proven, but many people swear by it.
The Cosmetic Ingredient Review (CIR) Expert Panel noted that the history of safe medical use of magnesium sulfate indicates no significant toxicity concerns relating to systemic exposure to this ingredient. Furthermore, the extensive clinical experience of the Panel, including the results of numerous patch tests, indicates that magnesium salts do not have the potential to induce sensitization. The Panel concluded that magnesium sulfate is safe in the present practices of use and concentration in cosmetics, when formulated to be non-irritating.
References: SaltWorks, “Epsom Salt Uses and Benefits”, Healthline, “Epsom Salt Foot Soak”, Cosmetic Ingredient Review, “Safety Assessment of Magnesium Sulfate as Used in Cosmetics”, 2014.