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Magnesium Stearate
AKA “Magnesium distearate, Magnesium octadecanoate, Dibasic magnesium stearate, Octadecanoic acid, magnesium salt, Synpro 90, Petrac MG 20NF, Stearic acid”
Synthetic
Ingredient Facts
Magnesium stearate
AKA: Magnesium distearate, Magnesium octadecanoate, Dibasic magnesium stearate, Octadecanoic acid, Magnesium salt, Synpro 90, Petrac MG 20NF, Stearic acid
Synthetic · Anticaking · EWG: 4
Plant-Derived Synthetic
Colorant
Plant Oil
Synthetic
Clean
A naturally derived powder that keeps formulas smooth and blendable while providing light hydration and helping ingredients stay evenly distributed in your product.
Solubility IN 100 CC WATER: 0.003 G @ 15 °C; 0.004 G @ 25 °C; 0.008 G @ 50 °C
Formula
C36H70MgO4
Mol. Weight
591.20
CAS #
557-04-0
Form
Powder
See origin →
Functions
Anticaking
Bulking
Colorant
Gives the product its color. Purely aesthetic — makes the formula look good in the jar but does nothing for your skin.
Moisturising
Locks In Moisture
Traditional Use
A synthetic compound developed in the 19th-20th centuries from stearic acid. Originally used in pharmaceuticals and later adopted by cosmetics as a thickening agent, lubricant, and anti-caking ingredient.
Skin Types
●all-skin-types
Best For
Dryness
Melanin-Rich Skin
Suitable
Pregnancy & Breastfeeding Safe
Yes
EWG
4
CIR
Safe
Pregnancy
Yes
CIR Safety Findings
Not a Sensitizer
medical-approval
all-shades-safe
Regulatory Status
USA✔ permitted
EU✔ permitted
JAPAN✔ permitted
CANADA✔ permitted
Amended Final Report on the Safety Assessment of Hydroxystearic Acid
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Final Report of the Safety Assessment of Lithium Stearate, Aluminum Distearate, Aluminum Stearate, Aluminum Tristearate, Ammonium Stearate, Calcium Stearate, Magnesium Stearate, Potassium Stearate, So
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Final Report on the Safety Assessment of Isostearic Acid
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Final Report on the Safety Assessment of Oleic Acid, Lauric Acid, Palmitic Acid, Myristic Acid, and Stearic Acid
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Final Report: Safety Assessment of Polyhydroxystearic Acid, Poly(3-Hydroxyoctanoic Acid, and Polylactic Acid as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
Re-evaluation: Safety Assessment of Hydroxystearic Acid as Used in Cosmetics
Cosmetic Ingredient Review (CIR) Expert Panel
International Journal of Toxicology
→
10-Hydroxystearic Acid
European Commission
EU Cosmetic Ingredient Database (CosIng)
→
Magnesium Stearate
European Commission
EU Cosmetic Ingredient Database (CosIng)
→
Polyhydroxystearic Acid
European Commission
EU Cosmetic Ingredient Database (CosIng)
→
Stearic Acid
European Commission
EU Cosmetic Ingredient Database (CosIng)
→
Hydroxystearic Acid
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
→
Isostearic Acid
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
→
Magnesium Stearate
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
→
Polyhydroxystearic Acid
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
→
Stearic Acid
Environmental Working Group (EWG)
EWG Skin Deep Cosmetics Database
→
Simultaneous contact sensitivity to hydroxystearic acid and C18-36 acid triglyceride in lip glosses.
Kimura M, Kawada A, Ogino M, Murayama Y
Contact dermatitis, 2002
→
Microemulsions based on TPGS and isostearic acid for imiquimod formulation and skin delivery.
Pescina S, Garrastazu G, Del Favero E, Rondelli V, Cantù L et al.
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2018
→
Bio-derived hydroxystearic acid ameliorates skin age spots and conspicuous pores.
Schütz R, Rawlings AV, Wandeler E, Jackson E, Trevisan S et al.
International journal of cosmetic science, 2019
→
Bio-derived hydroxystearic acid ameliorates skin age spots and conspicuous pores.
Schütz R, Rawlings AV, Wandeler E, Jackson E, Trevisan S et al.
International journal of cosmetic science, 2019
→
Bio-derived hydroxystearic acid ameliorates skin age spots and conspicuous pores.
Schütz R, Rawlings AV, Wandeler E, Jackson E, Trevisan S et al.
International journal of cosmetic science, 2019
→
Verified Feb 2026
Data: PubChem · CosIng · EWG · CIR