Parabens in the Human Body
Parabens can enter the human body through the skin and parenterally. The average daily total personal paraben exposure is estimated to be 76 mg, with cosmetics and personal care products accounting for 50 mg, 25 mg from pharmaceutical products, and 1 mg from food.[17–19] Parabens applied to the skin are metabolized by keratinocyte carboxylesterases and the conjugated metabolites are excreted in urine and bile.[20,21] Oral or intravenous parabens are metabolized by esterases within the intestine and liver. Parabens have been detected in urine, serum, breast milk and seminal fluid, but most worrisome has been the detection in breast tissue from patients with breast cancer.[2,22–26] Some have hypothesized that the higher concentration in the upper lateral breast near the axilla correlates with exposure from underarm deodorant and an increased incidence of breast cancer development in the area.[27,28] Still absolute concentrations indicate that levels of paraben within human fluids and tissue are low with average urine concentrations reported in the US ranging from 0.5 to 680 ng/mL and breast tissue concentrations ranging from 0 to 5100 ng/g of breast tissue (the median being 85.5 ng/g).[25,26] These low concentrations should be interpreted in the context of known estrogenic effects of parabens, which are discussed in the next section.
Skin Therapy Letter. 2013;18(2) © 2013 SkinCareGuide.com