Butylparaben, also called butyl paraben, butyl parahydroxybenzoate, or butyl p-hydroxybenzoate, is a chemical compound that is used as an antifungal preservative in various cosmetic products. Its molecular formula is C4H9(C6H4(OH)COO). Butylparaben shares several structural qualities with estrogen, and is thought to have some influence on human reproduction.
Parabens such as butylparaben are esters of of para-hydroxybenzoic acid. An ester is a compound that is, generally speaking, formed from the reaction of an acid and alcohol. Butylparaben is the butyl ester of para-hydroxybenzoic acid. A butyl is a chain containing four carbon atoms and nine hydrogen atoms. The C4H9 in butylparaben's molecular formula makes it a butyl ester.
Many cosmetic products make use of parabens. They can be found in shaving creams, moisturizers, shampoos, lubricants, and other cosmetic products where they serve as fungicidal and bacteriocidal agents. Commercially used parabens are synthetically produced, though many are similar, if not identical, to parabens appearing in nature. Butylparaben is also used as a suspension fluid in many medications.
There is much debate surrounding the wide use of parabens. They are considered safe because of a long history of supposedly-safe use, but their safety is recently questioned. Studies conducted in the early 2000s located traces of parabens in breast tumors. Some scientists claim that parabens in deodorants and body sprays could be responsible for enhancing cancerous cells. Leaders of the cosmetic industry deny any connection between the parabens and breast cancer.
Parabens are absorbed from the skin into the circulatory system and gastrointestinal system. Many are weak estrogen mimickers, and are able to bind to cellular estrogen receptors. Their mimicry of estrogen is said to cause an increase in the expression of genes that cause human breast tumors. The expression of these genes is usually regulated by estradiol, the primary estrogen that appears in humans.
While its use is debated along with other parabens, butylparaben is still used in cosmetics and in medicine. Its use as an antifungal preservative keeps cosmetic products usable for longer periods of time and promotes healthier skin, and its role as a suspension fluid in medications is useful for moderating the rate of release of chemicals into the body. However, its alleged links to breast cancer, if confirmed, could result in a marked decline in its use.