Parabens are a class of widely used preservatives in cosmetic and pharmaceutical products. Chemically, theyare a series of parahydroxybenzoates or esters ofparahydroxybenzoic acid. Parabens are effectivepreservatives in many types of formulas. Thesecompounds, and their salts, are used primarily for theirbactericidal and fungicidal properties. They are found inshampoos, commercial moisturizers, shaving gels, personal lubricants, topical/parenteral pharmaceuticals, suntan products, makeup, and toothpaste. They are alsoused as food preservatives.

Different types include methyl-, ethyl-, propyl-, isobutyl-paraben, etc. Parabens are widely used because they’re very effective at a low dose, especially compared to all the other preservatives out there. They have no smell or color, are very easy to use, and are generally well tolerated by our skin. At the same time, parabens are one of the most vilified ingredients in the cosmetic industry. The scrutiny seems to stem from a 2004 study, which found traces of parabens in breast tumors. It’s important to note that this study didn’t compare levels of parabens in normal breast tissue to cancerous breast tissue. Instead, journalists reporting on this study drew their conclusions based on the assumption that parabens were found at a higher level in individuals with breast cancer.

Today, parabens are thought to be weak estrogen mimics and potential endocrine disruptors, implicated in a variety of hormonal related problems such as breast cancer, testicular cancer, and declining sperm counts. With that said, in my research through the available literature, most of the conclusions related to adverse health effects were made from anecdotal assumptions or had really unrealistic methods. What do I mean? There hasn’t been a replicated study to show that parabens (especially the ones most commonly used in cosmetics, methyl & ethyl-) cause endocrine or hormonal disruption (especially at the dosage in your cosmetic products) in humans, and there hasn’t been a study that concluded with significant evidence that these chemicals cause the above health issues. Just because it’s seen in tissues doesn’t mean it’s causing harm. Correlation does not mean causation. More studies need to compare paraben concentrations in healthy tissues to diseased tissues, and to determine the actual biological effects (from amounts comparable to our exposure). With respect to the unrealistic methods, most of these studies included mouse models. In the studies, they often included high dose ingestion or frequent application of parabens. I say unrealistic because these would be over 100 times greater concentration for the mice than what’s in an entire cosmetic product. To add, we don’t typically use a product in one application. Instead, we’ll use it over a longer time frame, like a month in the case of shampoo. I’m not going to conclude that parabens are good or bad for our health, but it’s important to know the limitations of the research. More studies need to be done to say conclusively that parabens, at the low levels used in cosmetics, are damaging to our health.

It’s worth noting that, with respect to endocrine disruption, while parabens are a weak estrogen mimic, Butylparaben (one of the more estrogenic parabens, these effects increase with carbon chain length/branching) is 10,000 times less potent than estradiol, which they compete with to bind receptors to have an estrogenic effect. Due to a rapid metabolism of parabens, if they do have estrogenic effects, it’s probably not through directly activating estrogen receptors.

More concrete troubling conclusions seem to lie within environmental studies. For example, although more than 90% of parabens are removed from our wastewater via treatment plants, they’re still very frequently found in aquatic ecosystems across all of our oceans, particularly methyl- and propylparaben, despite being biodegradable. With that said, while they are found throughout our worldwide aquatic ecosystems, we don’t really know if they’re actually having an adverse effect on them. More studies need to be done, again, to determine the biological impacts of these ingredients. Given how much more potent our own hormones are, especially when we take things like birth control pills, how do parabens interact with the environment compared to our pee? So many questions yet to be answered.

In cosmetics, many paraben types have been tested to be well tolerated on our skin up to levels of 25%. In contrast, these ingredients typically range from 0.01 to 0.3% in a product. After extensive testing, parabens seem to be the least allergenic preservatives on the market. But, because of some of the research mentioned above, there’s been incredible pressure on the industry to find alternatives. Unfortunately, the alternatives are often more allergenic… which isn’t good news for our emerging skin allergy epidemic. This epidemic may be being driven by antibacterial agents, like parabens and other preservatives, by altering our skin microflora? There’s so much going on here and so much uncertainty now that we’re learning more about our bacterial inhabitants.