Since 2004, reports in the media and on the Internet have been made directing consumers to avoid parabens in personal care products, while a virtue is often made of products being paraben-free. Many of these reports are based on a 2004 study by Darbre et al. claiming to have detected parabens in human breast cancer tissue. That study was prompted by a 1998 study by Routledge et al. that found parabens to have oestrogenic activity. Papers have been published by this author regarding the validity of these two studies and while the full detail of those papers will not be repeated in this article, a short summary and discussion of other paraben studies is offered here.
In a recent online discussion about parabensa, one commentator suggested that the controversy surrounding the material has moved beyond scientific debate into the realm of consumer concern. This implies that scientific debate is no longer worthwhile. While it is difficult to change the perception of non-scientific consumers, this does not mean the scientific debate should cease; the facts do not disappear because a wealth of misinformation surrounds the issue.
Some of the worst offenders for promoting incorrect information about parabens are cosmetic manufacturers selling “natural” personal care products. Perhaps these manufacturers are unaware that methyl-, ethyl- and propylparaben exist in nature. While it cannot be claimed that their presence in nature guarantees their safety, parabens have been detected in various plant and animal species such as barley, strawberries, blackcurrants, peaches, carrots and Dytiscus marginalis (yellow beetle). Methylparaben has also been detected in the vaginal secretions of female dogs in oestrus.
As noted, negative statements about parabens and other “toxic” chemicals are made on the Internet, and these are often misleading and incorrect. One mistake that is commonly made is the grouping of parabens together as a single entity—such as in the statement, “Parabens are oestrogenic.” As is the case with the physical and chemical properties of parabens, there are differences in toxicological properties across the homologous series. For example, Routledge et al. found no oestrogenic activity for methylparaben in vivo in his 1998 study, and the activity of butylparaben was found to be 100,000 times weaker than oestradiol, the benchmark for measuring oestrogenic activity.