Parabens are used to prevent the growth of microbes in cosmetics products and can be absorbed through skin, blood and the digestive system . Parabens have been found in biopsies from breast tumors  at concentrations similar to those found in consumer products . Parabens may be found in a wide variety of products including shampoos, lotions, deodorants, scrubs and eye makeup, and are found in nearly all urine samples from U.S. adults regardless of ethnic, socioeconomic or geographic backgrounds . Adolescents and adult females had higher levels of methylparaben and propylparaben in their urine than did males of similar ages .
What you need to know
Found in: Shampoos, conditioners, lotions, facial and shower cleansers and scrubs
What to look for on the label: Ethylparaben, butylparaben, methylparaben, propylparaben, other ingredients ending in –paraben
Health concerns: Endocrine disruption, developmental and reproductive toxicity, allergies and immunotoxicity
Vulnerable populations: Pregnant women and young children
Regulations: Some forms of parabens are banned in Denmark (propyl and butyl paraben, their isoforms and their salts) in cosmetics products for children up to 3 years
What are parabens?
Parabens are actually several distinct chemicals with a similar molecular structure. Four of these are used frequently in cosmetics: ethylparaben, butylparaben, methylparaben and propylparaben. Methylparaben and propylparaben are the most common of these. Parabens are most common in personal care products that contain significant amounts of water, such as shampoos, conditioners, lotions and facial and shower cleansers and scrubs, in order to discourage the growth of microbes. While Cosmetic Ingredient Review recommends concentration limits for single and total paraben concentration in a single product, these recommendations do not account for exposure to parabens from several products by a single individual . A 2004 UK study detected traces of five parabens in the breast tumors of 19 out of 20 women studied . This small study does not prove a causal relationship between parabens and breast cancer, but it is important because it detected the presence of intact parabens—unaltered by the body’s metabolism—which is an indication of the chemical’s ability to penetrate skin and remain in breast tissue. A more recent study found higher levels of one paraben, n-propylparaben, in the axilla quadrant of the breast (the area nearest the underarm) . This is the region in which the highest proportion of breast tumors are found, although paraben concentration in the tissue samples was not related to location of breast tumors in individual women.
What are the health concerns?
Endocrine disruption: Of greatest concern is that parabens are known to disrupt hormone function, an effect that is linked to increased risk of breast cancer and reproductive toxicity. Parabens mimic estrogen by binding to estrogen receptors on cells. They also increase the expression of genes usually regulated by estradiol (a natural form of estrogen); these genes cause human breast cancer cells to grow and multiply in cellular studies . Parabens are also linked to cancer, reproductive toxicity, immunotoxicity, neurotoxicity and skin irritation . Since parabens are used to kill bacteria in water-based solutions, they inherently have some toxicity to cells .
How can you avoid this?
Look for products labeled “paraben-free” and read ingredient lists on labels to avoid products with parabens. Many natural and organic cosmetics manufacturers have found effective alternatives to parabens to prevent microbial growth in personal care products. Some companies have created preservative-free products that have shorter shelf lives than conventional products (six months to a year), but if used daily are likely to be used up before they expire.
Further information, including links to reports and press releases
 Gray, J (2008). State of the Evidence: The Connection between Breast Cancer and the Environment. San Francisco, CA: The Breast Cancer Fund.
 Daubre PD, Aljarrah A, Miller WR, Coldham NG, Sauer MJ, Pope GS (2004). Concentrations of parabens in human breast tumours. Journal of Applied Toxicology 24:5-13.
 Rastogi SC, Schouten A, Dekruijf N, Weijland JW (1995). Contents of methylparaben, ethylparaben, propylparaben, butylparaben and benzylparaben in cosmetic products. Contact Dermatits 32: 28-30.
 Ye X, Bishop AM, Reidy JA, Needham LL, Calafat AM (2006). Parabens as urinary biomarkers of exposure in humans. Environmental Health Perspectives114: 1843-1846.
 Calafat, A. M., Ye, X., Wong, L.-Y., Bishop, A. M., & Needham, L. L. (2010). Urinary concentrations of four parabens in the U.S. Population: NHANES 2005-2006. Environ Health Persp, 118(5), 679–685.
 Cosmetic Ingredient Review Expert Panel Meeting (2012). Parabens. http://www.cir-safety.org/sites/default/files/paraben_build.pdf.
 Darbre PD, Aljarrah A, Miller WR, Coldham NG, Sauer MJ, Pope GS (2004). Concentrations of parabens in human breast tumors. Journal of Applied Toxicology 24:5-13.
 Barr, L., Metaxas, G., Harbach, C. A. J., Savoy, L. A., & Darbre, P. D. (2012). Measurement of paraben concentrations in human breast tissue at serial locations across the breast from axilla to sternum. J Appl Toxicol, 32(3), 219–232.
 Byford JR, Shaw LE, Drew MGB, Pope GS, Sauer MJ, Darbre PD (2002). Oestrogenic activity of parabens in MCF7 human breast cancer cells. Journal of Steroid Biochemistry & Molecular Biology 80:49-60.
 Environmental Working Group. Skin Deep. Parabens. Available online: http://www.cosmeticsdatabase.com/ingredient.php?ingred06=704450&refurl=%2Fproduct.php%3Fprod_id%3D17311%26. Accessed December 9, 2008.
Environmental Working Group. Skin Deep. Methylparaben. Available online: Environmental Working Group. Skin Deep. Parabens. Available online: http://www.cosmeticsdatabase.com/ingredient.php?ingred06=704450&refurl=%2Fproduct.php%3Fprod_id%3D17311%26. Accessed December 9, 2008.
Environmental Working Group. Skin Deep. Butylparaben. Available online: http://www.cosmeticsdatabase.com/ingredient.php?ingred06=700868. Accessed December 9, 2008.
Environmental Working Group. Skin Deep. Propylparaben. Available online: http://www.cosmeticsdatabase.com/ingredient.php?ingred06=705335. Accessed December 9, 2008.
 Ishiwatari S, Suzuki T, Hitomi T, Yoshino T, Matsukuma S, Tsuji T. (2006). Effects of methyl paraben on skin keratinocytes. Journal of Applied Toxicology 27:1-9.