Magnesium stearate is a magnesium salt containing stearic acid. Stearic acid is an 18 carbon long saturated fat, common in our food supply. It is readily metabolized to oleic acid (the monounsaturated fat found in olive oil). Stearic acid is unique among all saturated fatty acids because it does not raise LDL cholesterol levels.
10% - 12% of cocoa is fatty acids of stearic acid, one of the richest sources of stearic acid in the food supply. It is easy to get 5 grams of stearic acid (5,000 mg) by eating a bar of chocolate. By comparison, a dietary supplement capsule product typically contains between 1% - 2% stearic acid or 10 mg - 20 mg of stearic acid per capsule, or 1000 mg to 2000 mg per bottle (20% - 40% of a chocolate bar for the entire bottle).
Stearic acid is also a common fatty acid found in meat, poultry, fish, grains, eggs, butter, and milk products. In meat, it is 1/3 of the saturated fat. The average intake of dietary stearic acid in American women is 5700 milligrams a day and in men 8400 milligrams a day. (
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My point is that the amount of stearic acid ingested in a vitamin product is a small percent of a fatty acid that you consume every day as part of your diet, a type of fatty acid that is not problematic in the first place.