A number of articles and Internet rumors over the years have reported an association between some parabens and cancer. It is implied in these reports that parabens can cause cancer by acting like estrogen, the female sex hormone, through a process called endocrine disruption. Some of these studies suggest a very weak estrogenic or endocrine disrupting effect of parabens. However, these studies, which have been conducted in animals, are observed only when they are dosed with extremely high amounts of parabens – far greater than anyone would be exposed to under actual conditions of use or with repeated use. These studies have been largely discredited by the scientific community; scientists who study the effects of products on the population have found no direct link between cosmetic products and cancer.
Many materials found in plants used as food also have an estrogenic effect. These naturally occurring materials are called phytoestrogens and are present in soy and other fruits and vegetables. Some of these phytoestrogens, when tested in the same way as parabens, give similar estrogen-like results. However, parabens have been shown to be 10,000 times weaker than the most potent phytoestrogens and 100,000 times less potent than estradiol, the estrogen produced naturally by the body. Most scientists agree that there is no endocrine- disrupting effect from the use of parabens in cosmetic and personal care products because their action, if any, is so weak.