Ingredient
Stearic acid
A fatty acid in soap, chocolate and tablets, and one word in the regulation that people consistently read as more than it says.
- INCI name
- Stearic Acid
- E number
- E570
- Also on labels as
- E570, Octadecanoic acid, Stearic Acid, Magnesium stearate, Glyceryl stearate, Sodium stearate
- Found in
- food, cosmetics, supplements
Part of Animal ingredients · Halal and kosher
Stearic acid is the reason a bar of soap is hard, a chocolate snaps, a candle holds its shape and a tablet comes out of the press in one piece. It is one of the most common fatty acids in nature and one of the most used in manufacturing.
Its regulation contains a phrase that gets misread more often than almost any other on this site.
Edible sources
The US regulation permits fatty acids, stearic acid among them, “manufactured from fats and oils derived from edible sources”.
That sounds like a restriction, and it is one. It excludes industrial tallow and inedible rendering.
What it does not do is mean vegetable. Beef fat is an edible source. So is lard. The phrase is about the grade of the raw material, not about which kingdom it came from, and a reader who takes it as a guarantee of plant origin has read a food safety provision as a dietary one.
What that leaves you with
The ingredient name is the same molecule whichever fat it started from, so no rule requires the origin to be declared and none is.
This is the same shape as Mono- and diglycerides, Glycerin and Polysorbate 80, and it is worth recognising the pattern rather than solving it four separate times: when a substance is defined chemically, the fat behind it disappears from the label.
Its salt, Magnesium stearate, inherits the question unchanged, which matters because that is where most supplement readers meet it.
The honest probability
Vegetable oils dominate, palm above all, because they are cheaper at scale and because a producer supplying certified products cannot afford the alternative.
We will give you that reasoning and we will not convert it into a yes. A tendency in an industry is not a fact about the packet in your hand, and the difference between those two things is most of what makes a label reader trustworthy.
The cosmetics version is bigger than the food one
On an ingredient list for a cream, stearic acid rarely appears alone. Glyceryl stearate, stearyl alcohol, cetearyl alcohol, PEG-100 stearate and the stearate salts are all built on the same fatty acid, and a single formulation may carry three or four of them.
That means one unanswered origin question can appear five times in one list and look like five problems. It is one, and the page for people avoiding animal ingredients takes the same view: find the pattern, then decide once.
Sources
- 21 CFR 172.860: Fatty acids US Food and Drug Administration, via eCFR · ecfr.gov Permits fatty acids including stearic acid and oleic acid, manufactured from fats and oils derived from edible sources.
- 21 CFR 101.4: Food; designation of ingredients US Food and Drug Administration, via eCFR · ecfr.gov