Every time you turn around, it seems there’s a new ingredient to avoid on someone’s warning list. Yet one class of potential toxins seems to be on everyone’s “avoid” list: phthalates. In beauty products, DBP (di-n-butyl phthalate) and DEP (diethyl phthalate) are most commonly found, in all classes of products ranging from hand lotions, nail polishes, deodorants, perfumes and cologne, aftershave lotions, shampoos, and hair gels. A third type, BzBP (benzylbutyl phthalate) is also used in some personal care products.
How the concern rose
Some experts tend not to be alarmed by the vast majority of animal studies. This is because animal studies can expose rodents to concentrations of compounds hundreds to thousands of times higher than the concentrations humans are exposed to with the typical use of products. That is part of the reason why many experts were not alarmed at first when high exposures of phthalates in rodents were found to change hormone levels and cause birth defects (CDC Third Annual Report, 2005).
In 2008, the United States National Research Council recommended that the cumulative effects of phthalates and other antiandrogens be investigated. It criticized US EPA guidances, which stipulate that, when examining cumulative effects, the chemicals examined should have similar mechanisms of action or similar structures, as too restrictive. It recommended instead that the effects of chemicals that cause similar adverse outcomes should be examined cumulatively, with other antiandrogens.
Work published in the journal Toxicology and Industrial Health reveals that male reproductive development is acutely sensitive to some phthalates. For example, the two phthalates most common in skin care products, dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP), produced dramatic changes in male sexual characteristics (e.g., hypospadias, decreased development) when exposure took place in utero, at levels far beneath those of previous toxicological concern. Dr. Shanna Swan, an epidemiologist at the University of Rochester Medical School, made headlines when she found a direct correlation between the levels of phthalates in a mother’s urine and the reproductive problems in young boys (CBS News, 2010).
What about breast cancer?
Although numerous reports have reported phthalates like DEP increase the risk of breast cancer, some research has shown that exposure to butylbenzyl phthalate (BBzP) of the monobenzyl phthalate (MBzP) metabolite shows a negative association with breast cancer (Odds ratio=0.46, p value for trend, p<.008). BBzP is less common than DEP, found in about one-third of products. It is proposed this finding may be associated with the demethylation of the estrogen receptor complex in breast cancer cells of BBzP resulting in a negative effect (Environmental Health Perspectives, 2010). Still, more research needs to be done to determine if this is the case, so don’t run out and slather BBzP on your skin anytime soon!
Over the past several years, a great deal of debate has risen over the safety of phthalates. Industry argues that the evidence is not substantial enough to demonstrate significant risk, as no single study has yet confirmed exposure to phthalates causes cancer or inhibits male reproductive tract growth. Yet even the CDC has gone so far as to advise pregnant women not to use cosmetics products that contain phthalates. Until more evidence is presented, it may be best to avoid phthalates in beauty products. Some phthalate-free brands include: