Sodium Citrate: The pH Balancer in Cosmetics
Arin Editorial · how this is made
You may wonder what sodium citrate is when you see it on a label. The name offers a clue: it's a salt derived from citric acid. It is loosely related to lemons.
What is this ingredient?
Sodium citrate is a salt made by neutralizing citric acid with sodium. It was first isolated from lemon juice in 1784, and industrial production began in 1890 with the Italian citrus industry. The same name can hide three different salts - monosodium, disodium and trisodium citrate; trisodium citrate is the most common in industry.
What does it do in cosmetics?
Its main job is to keep a product's pH stable. Skin is naturally slightly acidic, and maintaining this balance supports the skin barrier. It also works as a chelating agent: it binds to metal ions in water and stops them from breaking down other ingredients. In food, you will meet it as E331, an acidity regulator and emulsifier. Technical sources say a typical cosmetic use level can reach 12%; that's a formulation guide, not a legal limit.
What do lab records say?
EPA ToxValDB database has positive results in genetic damage tests: Ames test positive, micronucleus test positive, 5 positive, 0 negative. These records need to be evaluated together with dose, species and exposure route; a positive lab finding alone does not mean "carcinogen". In contrast, rabbit skin and eye irritation tests showed no significant irritation, and skin sensitization was not expected.
The US FDA keeps it on the GRAS (generally recognized as safe) list for food; it is widely used in cosmetics.
Don't panic when you see it on a label. It is also a food additive, so its safety history is broad. Its potential to irritate skin looks low; still, rinse eyes with plenty of water if exposed, and stop use if any allergic reaction occurs.
Sources
- EPA ToxValDB (postgres)