Triethyl citrate is a clear, oily liquid made by combining citric acid with ethanol. Despite its oil-like texture, it’s technically an ester, not a true oil. You’ll find it listed on ingredient labels for cosmetics, food products, pharmaceuticals, and fragrances, where it serves as a solvent, plasticizer, or fixative depending on the application. It has the chemical formula C₁₂H₂₀O₇ and a molecular weight of about 276.
How Triethyl Citrate Is Made
The production process is straightforward: citric acid reacts with ethanol in a process called esterification. Both starting materials can be sourced from biological origins (citric acid from fermentation, ethanol from plant sugars), which is why triethyl citrate is sometimes marketed as a “green” or biorenewable chemical. It’s considered an alternative to petroleum-based solvents in several industries.
Why It Shows Up in So Many Products
Triethyl citrate is versatile because it dissolves well in both water and many organic compounds. That dual compatibility makes it useful across very different product categories.
In food, it works as a flavoring agent, a solvent for other ingredients, and a surface-active agent that helps ingredients mix evenly. The FDA classifies it as Generally Recognized as Safe (GRAS) with no specific usage limit beyond standard good manufacturing practices.
In cosmetics and personal care, it functions as a solvent and carrier for other active ingredients. It helps formulations spread smoothly and can improve the feel of a product on skin. The Cosmetic Ingredient Review Expert Panel has assessed citrate esters in this family and found them safe as used in cosmetics. Clinical testing on humans showed no skin irritation or sensitization.
In fragrances, triethyl citrate acts as a solvent, diluent, and fixative for long-lasting perfumes. As a fixative, it slows the evaporation of volatile fragrance compounds, helping a scent last longer on your skin or clothing.
Its Role in Pharmaceuticals
One of the most important industrial uses for triethyl citrate is as a plasticizer in tablet and pellet coatings. When pharmaceutical companies apply thin polymer films to pills (to control where and how fast a drug releases), the films can be brittle and crack. Adding triethyl citrate at concentrations as low as 10% by weight significantly improves film flexibility, allowing coated pellets to survive compression into tablets without breaking apart.
Triethyl citrate is particularly valued in water-based coating systems because of its water solubility, which sets it apart from other plasticizers. Research on drug-release profiles has shown that triethyl citrate produces a steady, pH-independent release of medication. That consistency matters for drugs that need to deliver the same dose regardless of where they are in your digestive tract.
For coatings designed to survive stomach acid and release drugs only in the colon, triethyl citrate maintains system stability even at high concentrations (up to 50% of the coating formulation).
Safety Profile
Triethyl citrate has a well-established safety record. When it breaks down inside the body, it hydrolyzes into citric acid and ethanol, both naturally occurring compounds with low toxic potential. The rate of this breakdown is slower in humans than in rats, which means human exposure studies are more reassuring than animal data alone.
In cosmetic safety testing, clinical trials on human volunteers found no evidence of skin irritation or allergic sensitization. An earlier animal study using guinea pigs had flagged a related compound (acetyl triethyl citrate) as a possible sensitizer, but the CIR Expert Panel considered the human clinical data more relevant and concluded that citrate esters in this family are not sensitizers in real-world use.
The FDA’s GRAS designation for food use, combined with the cosmetic safety assessments, places triethyl citrate among the better-studied and more widely accepted ingredients you’ll encounter on a product label.
How to Identify It on Labels
You may see triethyl citrate listed under several names. Its commercial pharmaceutical name is Citroflex. On food labels it sometimes appears simply as “triethyl citrate.” In scientific literature, it goes by citric acid triethyl ester. If a product label says “triethyl citrate oil,” that’s an informal description of its oily liquid form rather than an official chemical name. Regardless of how it’s listed, it refers to the same compound.