What Is It?
Citric acid is a weak acid that is widely found in both plants and animals. It is a natural ingredient that is common in citrus fruits, for example, lemon juice , which contains about 5-8 percent citric acid. The dominant use of citric acid is as a natural flavoring and preservative in food and beverages, especially soft drinks. Citric acid is also a central compound in the citric acid cycle. The citric acid cycle is the pathway in many organisms, including humans, that produces nearly two-thirds of all of the energy used by cells.
Why is it used in cosmetics and personal care products?
Products containing citric acid and some of its salts and esters can be safely formulated for specific application to baby skin or use near the eye area or on mucous membranes. In addition, they may be used in cosmetic sprays, including hair, deodorant, body and other propellant and pump spray products. Citric acid is also one of a group of ingredients known as alpha hydroxy acids that are used as the active ingredients in chemical skin peels. Sodium citrate may be used in all types of cosmetic products, including baby products, make-up, lipstick, bath products, soaps and detergents, hair dyes and colors, and hair and skin care products. Tributyl citrate and triethyl citrate may be used in bath products, other cleansing products, and creams and lotions.
Citric acid and its diammonium, potassium and sodium salts are all used to help preserve cosmetics and personal care products by chelating (complexing) metals. Citric acid and its salts are also added to cosmetics to help adjust the acid/base balance. Other functions of the citrate ingredients include: Buffering agent , Cosmetic astringent , Cosmetic biocide , Hair fixative , Oral care agent , Plasticizer , Skin-conditioning agent – emollient , Skin-conditioning agent – miscellaneous , Skin-conditioning agent – occlusive , and Solvent .
The citric acid ingredients most commonly used in cosmetics are citric acid, sodium citrate, tributyl citrate and triethyl citrate. According to the 2016 U.S. Food and Drug Administration’s (FDA) Voluntary Cosmetic Registration Program (VCRP), citric acid was used in almost every category of cosmetic product with over 10,000 reported uses. The next most commonly used citric acid-derived ingredients were sodium, tributyl and triethyl citrate.
Sodium citrate is a salt derived from citric acid that is commonly used in cosmetics and personal care products. Other natural salts of citric acid that are used in cosmetics and personal care products include potassium citrate, aluminum citrate, diammonium citrate, ferric citrate, magnesium citrate, monosodium citrate and zinc citrate.
Tributyl citrate and triethyl citrate may also be used in cosmetics and personal care products. These ingredients are made by combining butyl or ethyl alcohol with citric acid and are called organic esters of citric acid. Other citric acid esters that may be used in cosmetics include Tri-C12-13 Alkyl Citrate, Tri-C14-15 Alkyl Citrate, tricaprylyl citrate, triethylhexyl citrate, triisocetyl citrate, trioctyldodecyl citrate, triisostearyl citrate, isodecyl citrate, stearyl citrate, dilauryl citrate and ethyl citrate.
The safety of citric acid and its salts and esters was assessed by the Cosmetic Ingredient Review (CIR) Expert Panel in 2014. Given that the FDA determined citric acid, calcium citrate, potassium citrate, sodium citrate and triethyl citrate as GRAS for use in food, in addition to the fact that citric acid is essential for the production of energy in cells in both plants and animals, the CIR Expert Panel focused on the potential for citric acid and its salts and esters to cause adverse effects when placed on the skin.
CIR reviewed scientific literature and data which indicated that at concentrations used in cosmetics and personal care products, citric acid and its salts and esters were not eye irritants, nor did they cause skin irritation or allergic skin reactions. Thus, CIR concluded that the available scientific data showed that citric acid, its salts, and esters were safe under current conditions of use in cosmetics and personal care products.
The CIR Expert Panel did note that although citric acid could be considered an alpha-hydroxy acid, it is also a beta-hydroxy acid making it distinct from the other alpha-hydroxy acids previously reviewed by the CIR Expert Panel (for example lactic acid and glycolic acid). The CIR Expert Panel concluded that the concern about increased sun sensitivity resulting from the use of alpha-hydroxy acid containing products was not relevant to products containing citric acid and its salts and esters because of the difference in chemical structure
Citric acid, calcium citrate, potassium citrate, sodium citrate and triethyl citrate are on the FDA’s list of direct food substances affirmed as Generally Recognized as Safe (GRAS ). FDA permits tributyl citrate and triethyl citrate to be used as indirect food additives in some food packaging materials.
Learn more about FDA Code of Federal Regulations for Citric Acid and its Calcium, Potassium and Sodium Salts, and Tributyl and Triethyl Citrates:
European Union (EU)
All of the ingredients reviewed by the CIR are listed in the European Union inventory of cosmetic ingredients and may be used in cosmetics and personal care products marketed in Europe according to the general provisions of the Cosmetics Regulation of the European Union.
The safety of citric acid and its calcium, potassium and sodium salts has been assessed by the Joint FAO/WHO Expert Committee on Food Additives. The most recent review concluded that these additives ‘do not constitute a significant toxicological hazard’ and it was therefore not necessary to set an Acceptable Daily Intake limit. As such, the amount in food is limited only by the amount needed to achieve the technical function within the product.