What is magnesium stearate made of?

Magnesium stearate is a lubricant and anti-caking agent used in many tablets, capsules, and other manufactured foods and supplements. It is made from magnesium (the mineral) and stearic acid (a fatty acid).

What are the two main ingredients?

Magnesium stearate consists of magnesium ions combined with stearate, which comes from stearic acid. In other words, it is the magnesium salt of stearic acid. [1]

Where does the stearic acid usually come from?

Stearic acid used for magnesium stearate can be derived from animal or plant fats and oils, depending on the manufacturing source. The final product is still magnesium stearate (the magnesium stearate compound), even though the starting feedstocks can differ. [1]

What does it look like and how is it used?

In most products, magnesium stearate is a fine powder. It helps powders flow more consistently during manufacturing and can reduce sticking to equipment, which can improve tablet/capsule production. [2]

Sources:
[1] https://en.wikipedia.org/wiki/Magnesium_stearate
[2] https://www.fda.gov/food/food-additives-petitions/food-additive-status-list-magnesium-stearate