Is lecithin always from soy?

Lecithin is an emulsifier: it keeps oil and water from separating, which is why it is in chocolate, margarine, baked goods and a great many cosmetics.

Most people meet it as Soy lecithin, and reasonably conclude the two words travel together. The regulation says otherwise.

Three plants, one word

The US definition describes commercial lecithin as “isolated as a gum following hydration of solvent-extracted soy, safflower, or corn oils”.

Three sources, one permitted name. Sunflower lecithin is also widely used and marketed specifically because it is not soy.

So “lecithin” on its own does not tell you the plant, in the same way that Mono- and diglycerides does not tell you the fat.

The part that makes this answerable anyway

Here the allergen rules do something they usually cannot, and it is worth appreciating.

Soy is one of the nine major food allergens. That means when lecithin is soy-derived, the statute requires the food source to be identified: either in a Contains statement after the ingredient list, or in parentheses inside it. That is why you see “lecithin (soy)” and “soy lecithin” rather than a bare word.

The practical inference is unusually clean. On a food label, lecithin with no soy identified beside it is not soy lecithin, because if it were, the law would have required the word.

Safflower, corn and sunflower carry no such requirement, because none of them is a major allergen, so they are the ones the bare word can be hiding.

Where the inference breaks

Cosmetics. The allergen statute is about food. On a cosmetic ingredient list the INCI name is simply Lecithin, with no source required, which is why the Soy lecithin page treats the cosmetic case separately.

Outside the US. Other markets have their own allergen lists and their own emphasis rules. Most treat soy as a declarable allergen, but the mechanism and the wording differ, and this inference is only as good as the rule behind it.

The short version

The word covers soy, safflower, corn and sunflower. On a food label the allergen rules force the soy case into the open, so the bare word points away from soy rather than towards it. On a cosmetic, the word tells you nothing at all, and the page on reading labels with a food allergy covers why those two documents behave so differently.