What is lecithin, and where does it come from?

Lecithin is a natural mixture of phospholipids, fat-like substances with one end that mixes with water and another that mixes with oil. Its main components are phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylinositol (PI). Most lecithin is recovered from vegetable oils, especially soybean oil, during refining, and some is made from egg yolk. In food, it is used as an emulsifier, the additive known in Europe as E322.

In short:

• What it is: a mixture of phospholipids, mainly PC, PE and PI, with smaller amounts of other lipids
• Where it comes from: soybean, sunflower, rapeseed and corn oil, and egg yolk
• How the types differ: the share of each phospholipid and the fatty acids they carry
• What it does in food: helps oil and water stay mixed (emulsifier E322)
• Daily amount: lecithin has no value in the Thai Reference Daily Intakes (Thai RDIs)

What is lecithin?

The word is used in two ways. In chemistry, "lecithin" can mean phosphatidylcholine itself. In food, it usually means a mixture of several phospholipids taken from a plant oil or from egg yolk.

What are phospholipids?

A phospholipid is built on a glycerol backbone carrying two fatty acids, with a phosphate-bearing head group. A 2026 review by Harasym and Wójcik explains that this head group makes the molecule amphiphilic, meaning one part mixes with water and the other with oil, and that in the seed, phospholipids form the single layer that coats the tiny oil droplets (oil bodies) and surround the membranes inside the cells. The head group gives each phospholipid its name, such as phosphatidylcholine or phosphatidylethanolamine.

Because one end mixes with water and the other with oil, phospholipids can sit where oil and water meet. This is why lecithin is used to keep oil and water from separating.

What does the US definition say?

US federal regulations describe commercial lecithin as a naturally occurring mixture of phosphatides, the group that includes phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol, with smaller amounts of other lipids. It is isolated as a gum after water is added to solvent-extracted soy, safflower or corn oil, may be bleached with hydrogen peroxide or benzoyl peroxide, and is dried by heating.

How does PubChem list lecithin?

PubChem, the chemistry database of the US National Library of Medicine, lists "lecithin" as one phosphatidylcholine molecule with the formula C42H80NO8P and a molecular weight of 758.1, carrying one 16-carbon and one 18-carbon fatty acid. Real lecithin is a mix of many such molecules with different fatty acids.

How is lecithin made from plant oils?

Plant lecithin is a by-product of oil refining. Crude oil pressed or extracted from seeds contains phospholipids, which are removed so the oil can be refined. The removed material, called gum, is dried to make lecithin.

How much phospholipid is in the oil?

The 2026 review by Harasym and Wójcik at Wroclaw University of Economics and Business in Poland gives about 1.5–3.0% phospholipids for soybean oil. Other oils have less: 0.5–1.04% for Styrian pumpkin seed oil and about 0.26% of the lipids in camelina oil bodies. Deoiled soy lecithin, from which most of the oil has been removed, is 65–75% phospholipids.

What is degumming?

The same review describes three degumming methods used in industry:

Each step lowers the remaining phosphorus by about tenfold. Because the method changes what is removed, lecithins from different processes also differ in composition.

Why soy and sunflower?

The review says soybean lecithin supplies most of the world market, while sunflower lecithin is the main commercial alternative to soy lecithin, used in chocolate, bakery and dairy products.

How do soy, sunflower and egg yolk lecithin differ?

They differ mainly in how much of each phospholipid they contain and in the fatty acids attached to them.

Phospholipid make-up of plant lecithins

Harasym and Wójcik cite a study in which a commercial flaxseed lecithin from Belarus was measured by HPLC under the same conditions as soy, rapeseed and sunflower lecithins. The figures are the share of each phospholipid within the phospholipids.

Source: Harasym and Wójcik 2026. The review does not list PE, PI and PA for soy and rapeseed lecithin, so they are not shown. The review reports a sunflower lecithin reference sample and a separate sunflower fraction analysed under the same protocol; their PE and PI figures differ.

Egg yolk phospholipids

Egg yolk is about 33% lipid, and a 2022 review by Abeyrathne and colleagues describes egg yolk as the richest natural source of phospholipids. Its phospholipids have a distinctive make-up: high in phosphatidylcholine, followed by phosphatidylethanolamine, sphingomyelin, plasmalogen and phosphatidylinositol. The review notes that all the lipids in egg yolk are held inside lipoprotein particles, and that they can be extracted with solvents or supercritical extraction, although their commercial use is still limited.

Is egg yolk always the same?

Fairly constant. A 1992 review by Kuksis at the University of Toronto says the hen's egg yolk has a remarkably constant lipid composition despite differences in feed and environment, and that this near-constant make-up makes egg yolk a reliable material for the baking, cosmetic and pharmaceutical industries. Changes in feed mainly shift the minor fatty acids in the yolk's fat rather than the lipid classes.

Where is lecithin found in food?

In foods naturally

Phospholipids are part of foods from both plants and animals. Abeyrathne and colleagues describe egg yolk as the richest natural source, and Harasym and Wójcik give about 1.5–3.0% phospholipids for crude soybean oil, which is why soybeans are the main raw material for plant lecithin.

As the food additive E322

Lecithin is added to foods to help mix oil and water, to stabilise texture and to keep fat from separating. In the European Union it is the authorised food additive E322. Egg yolk itself works the same way in cooking: a 2013 review by Anton at France's national agricultural research institute (INRA) explains that the plasma part of the yolk, rich in lipids, is responsible for the strong emulsifying properties of yolk.

Studies of lecithin in food

The Thai study by Panpipat and colleagues used surimi, the fish paste behind fish balls and similar products, and found that a small amount worked better than a large one: at 1.5 g per 100 g, the gel's breaking force fell and porous structures appeared. All the lecithin levels also slowed fat oxidation in the surimi compared with none. In the peanut butter study by Ibrahim and colleagues, the sample without lecithin separated the most oil. Both are laboratory studies of one food each, showing how lecithin behaves as an ingredient rather than what it does in the body.

Is there a recommended daily amount of lecithin?

No. The Thai RDIs, which cover nutrients such as vitamins, minerals and protein, do not include lecithin, so there is no daily reference value for it.

What did EFSA conclude about E322?

The European Food Safety Authority (EFSA) re-evaluated lecithins (E322) as a food additive in 2017. Lecithins had been evaluated earlier by the Joint FAO/WHO Expert Committee on Food Additives in 1973 and by the EU's Scientific Committee on Food in 1982. EFSA's panel concluded that there was no need for a numerical acceptable daily intake (ADI) and no safety concern for the general population over 1 year of age at the reported uses and use levels. For infants from 12 weeks to 11 months, it also found no safety concern at the reported uses. In the United States, lecithin may be used in food with no limit other than good manufacturing practice.

These conclusions cover lecithin used as a food additive at the levels reported by industry, not lecithin taken in larger amounts as a supplement.

Who should be careful with lecithin?

People who react to soy or eggs

Soybeans and eggs are among the nine major food allergens listed by the US Food and Drug Administration. Soy lecithin is made from soybeans and egg lecithin from eggs. Harasym and Wójcik explain that the allergenic potential of an oil or its lecithin comes from leftover seed protein rather than from the phospholipids, and that crude lecithins collected at the degumming stage keep more of this protein than fully refined oils. If you have reacted to soy or eggs, read labels and avoid products made from them.

People who take regular medication, or are pregnant or breastfeeding

If you are pregnant, breastfeeding, take regular medication or are under a doctor's care, speak to a doctor or pharmacist before taking dietary supplements, including lecithin.

Dietary supplements are not intended to prevent, treat or cure any disease.