Human exposures to parabens in cosmetics - a literature study

Abstract

A literature study was performed in order to assess and compare evidence of human exposure to parabens in cosmetics. The focus of the thesis is on human concentrations, the rate of dermal absorption, metabolism and excretion; in order to increase our understanding of human exposures to endocrine disrupting chemicals in cosmetics. High detection rates of native and total parabens in blood and urine were identified. GMs of native parabens were lower than total paraben levels in urine as expected, because parabens need to be conjugated before excreted. More research is required to determine medians or means of native parabens in human plasma and serum, as disparity exist between median concentrations measured in the two existing studies. Based on available evidence it was not possible to conclude on the percentage of dermal absorption, but it is indicated that higher exposures to native parabens occur when dermally absorbed in contrary to orally. As paraben exposures are widely occurring and parabens have a half- life of less than 24 hours, regular or constant exposures are identified. Regular or constant exposures do most likely occur from the use of cosmetics, which is in conformity with evidence showing both higher cosmetic use and higher GMs of parabens among women than men. Elevated paraben exposures among women can also cause exposures to the most vulnerable groups; the fetus and breastfeeding infant. However, further research is required to investigate to what extent these EDCs with short half- lives reach the fetus and the infant through breast milk. Further research is also required to investigate effects of parabens in combination with other compounds, the so- called cocktail/ mixture effect, as this has been a neglected area in international studies. Based on available evidence it can be concluded that strong evidence exists on widely occurring paraben exposures among humans.