Magnesium Stearate vs. Stearic Acid: What's the Difference?

You might have seen magnesium stearate on an ingredients list and wondered about it. It's a common ingredient that can be found in many nutritional supplements.

Magnesium Stearate

• Magnesium stearate is a salt that is made of two anions of stearic acid and one magnesium cation. This means it is a new compound formed when the positive ions from stearic acid combine with magnesium.

Stearic Acid Similarity

• Magnesium stearate is not the same thing as stearic acid, but a compound that is derived from it.

Stearic Acid

• Stearic acid is a saturated fatty acid found in many animal and plant sources, such as cocoa and beef fat.

Criticism

• Some nutritional supplement manufacturers are alleging that magnesium stearate is harmful. This is despite FDA approval and despite a general lack of evidence to back up their claims.

Magnesium Stearate Uses

• Magnesium stearate is used to help bind ingredients in pills and as a filler.