Parabens are one of the most widely and heavily used antimicrobial preservatives, which until recently, were found in up to 99% of cosmetics and toiletries. Typically, more than one paraben is used in a single product and they are often used in combination with other chemical preservatives and are commonly used in facial moisturisers, lipsticks, eye‑shadow and mascara, body sprays, deodorants, hair removal creams, shaving gels, body lotions, face creams, sunscreens, toothpastes, cleansers and shampoos. It is probably easier to say what they are not found in.
Unfortunately, multiple studies have also identified parabens in most of the personal care and cosmetic products analysed even if they were not mentioned on the label. In a study of personal care products methyl paraben was detected most frequently and at the highest concentrations. The highest concentration was in an “alternative” sunscreen. Of the 11 conventional samples with detectable parabens, 10 included products with “paraben” on the label. Nevertheless, in “alternative” products, the study found parabens in 7 products, including 3 sunscreens, that did not list parabens on the label. One study of the 215 common cosmetic products tested 93% contained parabens. Not only are they not be listing parabens on the label but manufactures may hide the chemical under the word ‘fragrance’, a collective term which covers over two thousand chemicals (Williams, 2004) or as the research shows they may not even label them as ingredients.
Parabens can be absorbed through application on the skin and able to enter the blood based on their fat loving (lipophilic) properties. As the vast majority of cosmetic products containing parabens are usually applied to the skin, it can be a major source of exposure. Average exposure to parabens is estimated to be around 76 mg per day which includes 1 mg daily from food, 50 mg from cosmetics and 25 mg from pharmaceuticals. Between 20 and 50 times more is taken in through the skin than food. As a result, extensive distribution of parabens in human samples, including milk, urine, semen, breast tissue and blood, has been reported over the past decade and widespread studies have now shown 2 or 3 or more paraben in 99% of the general population in many countries around the world.
Paraben absorption can also be enhanced by the presence of other chemicals such as ethanol, menthol and propylene glycol, which occur in a many commonly used cosmetic products Because parabens tend to accumulate they can be found in elevated concentrations in some tissues. In one study after eight hours of contact with skin 60% of methylparaben, 40% of ethylparaben and 20% of propylparaben were found to have permeated across the skins surface.
A number of studies have now shown higher paraben concentrations with increasing use of PCPs used in the past 24 hours. In particular, the use of colognes and perfumes has been associated with increased methylparaben concentrations in both adults and 8–13 year old children. Other PCPs associated with increased methylparaben concentrations include lotions, colored cosmetics (hair dye, foundation, blush, eye shadow, eye liner, or mascara), aftershaves and nail polish in adults and hair care products and deodorants (girls only) in children.
Many studies have now linked parabens to reproductive, endocrine, respiratory and other health problems including cancer, birth defects, infertility, contact allergies, and a host of other problems. Many studies have suggested possible chronic health effects of parabens, including increased risk of breast cancer and prostate cancer through estrogenic activity, and possibly increased risk of skin cancer. Parabens have also been linked increases in estrogenic activity in children, leading to decreased fertility in males early puberty in females including early breast development.
Natural estrogens act in target cells by binding to estrogen receptors which function to regulate gene expression. However, parabens have the ability to remain longer within the body and accumulate than their short‑lived natural counterparts. Studies have also found the estrogenic effects of parabens at doses at the same levels reported in many studies.
A number of studies have suggested that products containing parabens that are regularly used around the breast area, are contributing to the increase in breast cancers. In particular, products such as deodorants and anti-perspirants applied to, and left on the underarm area for long periods, thus able to absorb through the skin and accumulate in the underlying tissue. Studies show that around 54% of incidences of breast cancer were located around the underarm area.
In addition, an analysis of breast tissue samples collected during mastectomy performed for primary breast cancer showed that at least one paraben was detectable in virtually all samples (99%) because estrogen is known to play a central role in the development, growth, and progression of breast cancer. The mechanisms by which parabens contribute to breast cancer is now well established and shows they enable multiple cancer steps. Of great concern is also that combinations of different parabens can produce additive effects on proliferation and most paraben containing products have multiple parabens in them. They can act synergistically to increase breast cancer gene expression and the presence of multiple estrogen receptors and other areas where they can bind in breast tissues may even increase the activity of parabens.
The influence of paraben on estrogen activity may be exacerbated by the fact that many personal care products containing parabens are applied directly around the breast area, as is the case with underarm deodorants and body moisturisers. Clinical studies over the last decade have indicated the majority of breast cancers occur in the upper‑outer quadrant of the breast near to the underarm area where products are applied. Not only are these products then able to be directly absorbed but regular re-application can promote the bioaccumulation of paraben in breast tissue. Underarm cosmetics can penetrate the skin more efficiently as they are applied to an area which usually has nicks and abrasions, caused by shaving and other forms of hair removal. The frequent application of these PCPs and the fact that they are left upon the skin of the breast region means that the dermal area is constantly and regularly exposed leading to accumulation in the underlying tissues.
Studies as early as 1983 have suggested links with negative reproductive effects. This study found that six preterm infants had significant concentrations of methyl paraben and its metabolites present in their urine. While more recent studies have found that exposing pregnant female mice to small levels of environmental estrogens could lead to a termination during early pregnancy.
In recent decades reproductive and developmental problems have become more prevalent—for example, data from the Centers for Disease Control and Prevention (CDC) show that male reproductive problems, including undescended testicles and hypospadias, doubled between 1970 and 1993. A rising concern has emerged regarding possible adverse effects of chemicals in cosmetics and PCPs on human reproduction outcomes. In developed countries about 15% of human couples are affected by infertility, almost half of these cases attributed to men, through low sperm motility or/and sperm count. Since they tend to mimic female hormones, these compounds especially affect male reproductive function.
Products containing parabens have been linked to negative effects on the male reproductive system and that exposure to paraben, particularly butyl paraben, while in the womb and in young males can lead to decreased testosterone levels and reduced sperm counts. Parabens appear toxic to the mitochondria and adversely affect mitochondrial function in the testes. The daily sperm production and the efficiency in the testes decreased dramatically in the test groups who received parabens. The sperm counts in the studies decreased in a dose dependent manner, that is the higher the paraben levels the lower the sperm counts. Other studies have also shown exposure to pregnant female rats led to male offspring with decreased testes, seminal vesicle and prostate gland weights, as well as decreased sperm count and motility.
Parabens have also been associated with allergic reactions (sensitisation); commonly rashes, swelling and itchiness and contact dermatitis (skin inflammation). An extensive range of adverse effects on the skin have been reported, including changes to cell structure, changes to gene expression, protein synthesis and cell death, following one month daily application of paraben based formulations. Studies are also showing chronic skin application of parabens may lead to prolonged estrogenic effects in skin. Estrogens are very important hormonal regulators in the skin and function to preserve collagen content, which supports and maintains elasticity thickening of the skin and wound healing. Daily application of products containing methylparaben to the skin found that the methylparaben remained unmetabolised on the skin and affected the ability of the skin act as a protective barrier so dermatological disorders, skin irritation and skin allergies often follow. Short term application to the skin of animals resulted in edema, which is swelling due to a collection of fluids, desquamation, which is a shedding of the skin, and erythema, which is a reddening of the skin due to dilation of the blood vessels. Similar affects have also been observed in human studies.
Overall this is a group of chemicals that we really do need to avoid but even reading the labels does not guarantee there will be no parabens.
