Written by Dr. Joshua Townley, BForensSc, PhD.
Paraben. You’ve probably heard by now that they’re the latest skincare ingredients to be vilified and shunned by celebrities and bloggers across the internet. The mere fact that so many new products claim to be ‘paraben-free’ seems proof enough to convince many people that they must be harmful in some way.
But does this preservative deserve its reputation as skin care villains, or have they been falsely accused? Let’s take a closer look at the evidence.
Exhibit A: Parabens and breast cancer
Parabens are known to bind weakly to estrogen receptors, and in 2004 one study detected parabens in breast cancer tissue samples1. That sounds fairly incriminating, like catching a burglar at the scene of a robbery, until we dig a little deeper. The study only looked at a small sample of tumours (20), didn’t compare healthy tissue, and most importantly, the blank samples with no tumour material were also positive for parabens, suggesting contamination. In fact, some of the “blank” samples showed higher levels of the preservative than the tumour samples.
The author herself later clarified that the study never claimed that parabens were the cause of the tumours, and a review published in 2015 concluded that ‘to date, no human studies have shown convincing evidence that parabens cause and stimulate breast cancer2. The same conclusion was reached by the SCCS*,3 a NICNAS^ Human Health assessment4, and the CIR† Expert Review Panel5. To return to our burglary analogy, simply being in the vicinity of a robbery doesn’t make you the guilty party.
Exhibit B: Parabens are toxic
Parabens have been used in food, medicines and cosmetics for almost a century. In food, parabens are broken down in the gut and rapidly pass through the body4. In cosmetic products applied to the skin, they are broken down by enzymes in the skin, leaving only about 1% to be absorbed into the body, and even that is quickly broken down and excreted in the urine5. While trace amounts may remain in the body, there’s no conclusive evidence that they cause any harm. Overall, parabens are considered to be non-toxic4.
Exhibit C: Parabens and skin irritation
Pick virtually any ingredient from the back of any cosmetic product, and I’m sure you’ll find evidence that someone out there has reacted badly to it, regardless of whether it’s synthetic, natural, organic or the blood of a mythical creature. Preservatives as a group are typically among the first suspects when someone visits their dermatologist after an allergic reaction to something they’ve put on their skin, and parabens are sometimes the culprits.
However, an Australian study that looked at the frequency of positive patch-test results to common preservatives grouped parabens among the least frequent sensitisers, responsible for only 1.1% of cases6. What’s more, unlike some other preservatives introduced as paraben replacements, this figure hasn’t shown any signs of increasing in the last 20 years5.
Exhibit D: Parabens and infertility
Studies in laboratory animals have shown that parabens can have an effect on male fertility7. That doesn’t sound good, but before we reach a verdict, consider this: the animals were exposed to much higher concentrations of parabens than those allowed in cosmetic products. Other studies that looked at similarly high paraben doses on fertility found no adverse reproductive effects5. Based on the available evidence, it’s very unlikely that real world use of products containing low levels of parabens have any influence on fertility.
Parabens are widespread in food, cosmetics and medicines, and play a vital role in preventing the growth of harmful fungus, bacteria and other microbes. Without preservatives like parabens, these products would be lucky to last more than a few weeks on the shelf. Because they are so widespread, it’s vital that researchers continue to look into possible harmful effects, and that the debate continues, however, for now, despite the concerns, this preservative remains among the most well-established and well-tolerated options available.
For now at least, we find the defendants: not guilty.
