Um.. sorry about the dramatic title, that’s just the forensic scientist in me. My post may not be as dramatic as the title suggests, but I wanted to explore the controversy surrounding synthetic preservatives in cosmetics, in particular the use of parabens, and to judge with my own opinion whether this controversy and the associated scaremongering marketing tactic is justified by real science and critical judgement.
I’ll note here, I was inspired to write this post after picking up ‘The Preservatives Handbook’ that LUSH has published (and it’s free in store). It’s a seriously good read if you want to get clued up on preservatives, natural or synthetic. This post is not going to have half a dozen pretty pictures or featuring cosmetics products, nothing like that. This will be a wordy, topical post about a current issue in the cosmetics industry and one I believe is worth talking about. You might need a fair few minutes to read this one.
Is it absolutely necessary to have preservatives in cosmetics?
YES, pretty much every beauty product you have will have preservatives in it. They are necessary to protect consumers from infection by preventing microbial spoilage, therefore prolonging the shelf life of your beauty products. Water, oils, carbohydrates and peptides in products are a good growth medium for microbes and this needs to be controlled.
Whether it’s a moisturiser, mascara or powder, without preservatives your products would be completely vulnerable to microbial attack – and this leads to risks of infection to your eyes, skin and mucous membranes. Some products do not have any preservatives but these usually will have a very short shelf life and will generally need be used in a few weeks as opposed to a few months or years depending on what the product is.
It’s important to note here that there can exist both synthetic and natural preservatives. Synthetic preservatives include the infamous parabens, phenoxyethanol, potassium sorbate and benzyl alcohol. Natural preservatives include ingredients like glycerine, honey and certain clays like kaolin even have microbial fighting properties. There are a tonne of brands and products now boasting ‘preservative-free’ formulas but really some of these can be misleading once you look at their ingredients list to discover some natural preservatives. In this case it’s not ‘preservative-free’ but rather ‘self-preserving’, as it contains ingredients that serve a double purpose as moisturisers or humectants (like honey for example) and preventing microbial attack at the same time. Another one you might notice is the term ‘paraben free’ but this doesn’t necessarily mean there are no synthetic preservatives, just that other alternatives could be used which may or may not include other synthetic preservatives.
Synthetic Preservatives and How They Work
Synthetic preservatives are manufactured in labs to be extremely effective in inhibiting the reproduction of microbes that inadvertently enter a product either during the manufacturing process or during consumer use. The European Union (EU) regularly monitors the use of synthetic parabens and any relating scientific studies or clinical trials, as well as setting upper limits on the maximum concentration of these preservatives in products. Many preservatives have been banned as a result of these studies and reviews mostly because there is a lack of data or risks associated with their use including adverse reactions.
As already mentioned, common synthetics such as methyl-, propyl- and butyl – paraben as well as benzyl alcohol are often used in combination because they work synergistically to inhibit microbial growth. Methylparaben and phenoxyethanol work by disrupting the membrane potential of bacterial cells, essentially leaving them unable to function. Other synthetics like propylparaben and benzyl alcohol work by preventing these cell walls from forming in bacteria progeny, again, leaving them unable to form and reproduce.
If synthetic preservatives are so effective, why do parabens have a bad name?
I’d like to ask you all a question here. No doubt you’ll all raise your hand if I ask you if you’ve ever seen the statement ‘paraben-free’ on product packaging, but I wonder how many of you would keep your hand raised if I asked you if you knew the real reason why some companies have avoided parabens, or even, why some companies continue to use parabens? Marketing strategies for the anti-paraben movement are particularly good at using buzzwords and scaremongering phrases to scare people off using paraben-containing products, and a lot of the time this is enough to persuade consumers to avoid them. But is this media-fuelled reputation of parabens warranted? I give my thoughts on this issue based on my own research from good quality sources.
Parabens may be linked to cancer?
Parabens have actually been used safely for decades in the cosmetics industry, until a 2004 study by Darbre was published which associated parabens to breast cancer. This study has now become one of the most famous studies of parabens, but not always for good reasons. In quick and simple terms, the study found traces of methylparaben in human breast cancer tissue. What this sparked, was a heated and lengthy debate on exactly how parabens are linked to cancer, and one that still continues today. The interpretation was, was that the presence of parabens in breast cancer tissue revealed that these parabens in cosmetic products were being absorbed into our body and caused the proliferation of cancerous cells (though this was not actually stated in the paper, these were how the results were then interpreted by the media and public). In an earlier study, parabens were found to have oestrogen-like activity, meaning they can act like our female sex hormones. Oestrogens have been known to play a role in the development and growth of breast cancer, again adding to the belief that exposure to parabens which have an oestrogenic activity can cause breast cancer. Interestingly though, the oestrogenic effect of these parabens is actually less than some naturally occurring oestrogens in the food we regularly consume such as dried fruits, green beans, chickpeas and flaxseeds. AND, oral contraceptive pills have a much more potent oestrogenic effect. Because of this, I’m not so sure this is actually a strong argument for the anti-paraben movement.
But what I find concerning about this particular study and the interpretations of the data is more to do with their study design. Most concerning, is that they actually found traces of intact methylparaben in their negative controls. What this means, is that even in blank samples containing no breast cancer tissue, parabens were still detected. In criminal trials, if a forensic scientist presents evidence where there is positive results for DNA in blank samples the evidence would be thrown out! How can you be sure that the parabens in the breast cancer samples come from the actual cancer tissues if you are detecting them in blank samples? Furthermore, it’s been shown by numerous studies that methylparaben is quickly metabolised in the liver, excreted in urine and thus finding intact parabens in high concetrations in the tissues would be highly unlikely. In the study, healthy breast tissue should have also studied in parallel as a direct comparison to cancerous tissues. Finally, another point is whether the levels of paraben detected in the samples would actually have oestrogenic activity, seeing as they were much lower than the previous study which first demonstrated the oestrogen activity of parabens.
It’s important to note here that this finding does not imply that one of the causes of breast cancer is the use of parabens, as much as the media and public believe so. In fact, the authors of the study actually released a statement after the media frenzy:
“Nowhere in the manuscript was any claim made that the presence of parabens had caused the breast cancer, indeed the measurement of a compound in a tissue cannot provide evidence of causality.”
So even the authors felt the need to clarify the results and the interpretations of the study, because they found that the media and the public were blowing their results way out of proportion. This is not an isolated issue in science communication unfortunately. Other examples include people saying that red wine helps you lose weight based on a study on reservatrol (the authors of the study again released a statement saying this interpretation was incorrect), and how some people claim that because hyaluronic acid is processed in a lab by a certain bacteria that can be found in a horse disease, we are essentially putting that horse disease on our faces LOL. Off track, but it shows that the media and the public love to twist the results of some studies into stories that will cause a frenzy, especially for parabens in an age where literally everything is thought to be carcinogenic now.
A more recent study however, showed that a combination of parabens lead to an increased proliferation of human breast cancer cells, but this study was performed on cells that were cultured in a lab outside of the human body, and many people believe the study design was not a realistic reflection. It didn’t take into account the crazy physiological processes that happen inside the complex human body, that would likely alter these results. The chemical was also directly applied to the cells, and this simply does not happen in reality when we use products containing parabens, where skin is a major barrier to the absorption of cosmetics.
Parabens may have an environmental impact
Another issue with parabens is their potential negative effects on the environment. Parabens are very stable, and as such do not break down in water. When we wash away our products that contain parabens, we are contributing to water pollution. Obviously, this adds to the already problematic issue of water pollution and could have significant knock-on effects to our ecosystems. While it’s debatable whether the small concentrations of parabens would contribute on a negligible scale, this is another reason why some people prefer natural alternatives like honey and sea salt.
The other thing to note here is that while they are very stable, some people can have allergic reactions to them and although this is pretty rare (up to 1.7%), this is a good enough reason to avoid them if you have sensitivity to them!
Could parabens be disrupting our hormone system?
Edit: This section was added in after I was asked about this particular topic so I thought it was then a good idea to include it 🙂
A thorough review article on the studies relating to parabens as endocrine disruptors was conducted and is a fantastic article for a critical review of the data.
- “Overall, the available studies reveal rather low levels of free parabens in blood of exposed humans and low or no free parabens in experimental animals. However, total levels of metabolites and parent compounds excreted in urine of orally and dermally exposed rats and rabbits are high, indicating that parabens and/or their metabolites are taken up in considerable amounts but rapidly metabolized and excreted. “
- They reference a paper that apparently found a reduced spermatogenesis in rats that were fed paraben esters orally (I must emphasise the oral delivery as this is not a true reflection of the way we use cosmetics). In the study they found propyl and butyl parabens as the esters which have an effect, and this is in line with the EU recommendations of lower concentrations. However, the data from the study was not made available for other labs and the EU to analyse and review and this is BIG NO NO in science. No one can actually confirm the results and interpretations of that study so the EU acknowledge there is doubt on this study.
Furthermore, this study was replicated by another lab and they found NO significant effects of these esters on their rats at all dose levels. So the whole thing is very confusing and in my mind if it’s not solid evidence, I can’t really put my belief in it. Even in this study, they found a reduced level of testosterone in the rats but this was in line with the development stages of rats and so this result was considered not scientifically valid.
- Another study found an increase in size of prostates in rats after administration of estrogenic compounds however, again this part of the study had no raw data available for review and analysis by authorities so the validity of this result was also called into question.
- “In conclusion, the reproductive toxicity studies on parabens appear to be insufficient. No studies on effects of subcutaneous exposure of young males have been reported, but only dietary studies. Subcutaneous exposure is relevant for paraben studies, as the first-pass effect (metabolism in liver) is avoided similarly to human exposure to parabens via dermal application.” E.g. You can’t take a result from dietary delivery and assume this will be the same for cosmetics when we don’t eat them but topically apply them.
- “The estrogenic activity of parabens is known to increase with increasing chain length and with branching of the alkyl chain” – these refer to the longer chain esters which have already been banned by the EU but not for methyl, ethyl, propyl, and butyl parabens.
- They note that parabens are weakly estrogenic but have a lower binding affinity for estrogen receptors compared to the estrogen ligands already present in our body eg, they are likely outcompeted by our own natural estrogens. However, I haven’t done enough reading to confirm this.
- “According to studies in humans, less than 2% of unhydrolyzed paraben is present in a free form in urine, whereas the majority of paraben is present as a glucuronidated or sulphated conjugate. Although conjugated forms are assumed to be rapidly excreted it has not been clarified whether these conjugated parabens may have any potential endocrine disrupting effects” eg only 2% of parabens are found intact in the urine and the majority are rapidly metabolised in our body. It is unsure whether this small percentage could actually be disrupting the endocrine system.
I could go on forever, but this is a good article if you want a critical review of the evidence presented for parabens being endocrine disruptors (referenced below)! Also, I’ll just state the obvious here: human are not rats (shock!), so how realistic can these studies be given our physiology would be different to that of a rat?
The aftermath and what it meant for parabens
Because of the 2004 study, parabens became arguably the most studied preservative out there. It opened up many questions that led to many further investigations. The Annex V, a list of allowable preservatives under the EU, governs the use of preservatives in the nations of the EU. Methyl-, ethyl-, propyl-, and butyl- parabens (which are the most common in cosmetics) are still part of the Annex V, because they are still deemed safe to use by the EU after so many studies and reviews.
The Scientific Committee on Consumer Safety (SCCS), released a final opinion on parabens based on a plethora of scientific data where they concluded parabens to be safe to use, however suggested a lower concentration for the propyl and butyl paraben esters due to their “weak endocrine-modifying potential”, but not for methylparaben or ethylparaben. The current limit is 0.4% concentration if used in singular, or 0.8% total concentration if a combination of parabens are used in a single formulation.
The FDA conducted their own research into the possible link to cancer and were satisfied that there were no direct links to the causes of cancer, and stated that there is no real reason for consumers to be concerned about their health when using products containing parabens. The American Cancer Council and the Personal Care Products Council both declare parabens safe to use in products as well. Within Australia, the Therapeutic Goods Administration (TGA) is the regulatory body and they have pretty rigorous reviews on these type of matters. Again, they claim they cannot find enough evidence to substantiate the idea that parabens are harmful ingredients.
Because of such rigorous testing and interpretation of scientific data, many organisations and scientists believe they are now one of the safest synthetic preservatives compared to other preservatives which have not been so extensively studied. We now know more about them than any other preservative out there. Despite these findings, parabens continue to be under fire and probably always will now. I think there has been too much damage done to their reputation as harmful ingredients that I think the anti-paraben movement will continue no matter how many organisations declare them safe to use.
So what are the alternatives?
For those who are concerned about parabens, rest assured there are alternatives you may want to consider, both natural and synthetic. But I want to stress this, ‘natural’ ingredients do not always mean they are safe for use, and ‘chemical’ or ‘synthetic’ doesn’t always mean they are dangerous. Parabens are made synthetically in a lab for preservative purposes, but they are actually naturally occurring too in many foods we eat.
There are natural ingredients you can use which have preservative properties as I’ve mentioned before like honey, glycerine, plant extracts and essential oils and clay. But just because a ‘natural’ based company states they are paraben-free, does not mean they aren’t using other synthetic alternatives (which haven’t been used as long and aren’t as rigorously tested as parabens anyway), and I’ve actually seen this in some ‘natural’ products! But it’s important to note that natural preservatives like essential oils and organic acids are much less effective and can still cause irritation. Even with these natural preservatives, they should be tested with as much rigor and methodical risk-based approaches as synthetic ones – it should be a level playing field.
You could avoid preservatives altogether, but the products you’d be using could be extremely dangerous to you if they are accumulating microbial colonies that could cause severe infections and even blindness. Here, I see this risk as a much bigger one than the tiny risk that parabens pose. The risk is actually higher in products that are naturally based, as microbes love to feed off these type of ingredients. Of course, powders and solid products are better preservative-free options, as they don’t have ‘free-water’ in their formulas which microbes need to grow. But good practice is needed to ensure these products aren’t used in an environment where they can collect water because then that’s thrown out the window.
There are options for single-use packaging, like we’ve recently seen with face masks, vitamin C serums etc, and also the potential for aseptic packaging. But these will become less and less realistic because of the additional cost of the packaging (which we would pay higher prices for in the end) and because of the waste burden they would pose on our environment.
My personal verdict
Based on the readings I have done and the scientific data I’ve interpreted, I really do not think the reputation of parabens as harmful ingredients to our health are substantiated by the ‘evidence’ presented. I don’t find any of the results to be conclusive evidence, nor direct links to cancer. In my opinion, the environmental impact is more of a concern than the perceived carcinogenic effect of parabens. The concentrations used in cosmetics are so little and deemed safe by so many health organisations that I struggle to buy into the scaremongering that a lot of brands and companies who advocate for paraben-free products impose on us consumers.
However, at the same time I am not against companies or brands that choose not to use synthetic preservatives. I just hope that those decisions aren’t made based on the ‘cancer risk’ theory that dominates the reputation of parabens. And I encourage people to look a little deeper into these type of things and not believe the hype in the media or marketing campaigns that is generated around labelling certain ingredients as harmful without a strong backing of evidence. I’m personally not going to avoid products containing parabens, but I’m not going to avoid products that don’t contain parabens either. I do know that some people are concerned though and for them, it’s a good thing that there are companies out there who use other alternatives. Just as long as they are still effective and just as safe, there should be no issues!
What’s your views on parabens? I’d really like to know and generate discussion so let me know in the comments!
The current recommendations under the Annex V of the EU can be found here.
Routledge, E.J., Parker, J., Odum, J., Ashby, J., Sumpter, J.P. 1998. Some alkyl hydroxy benzoate preservatives (parabens) are estrogenic. Toxicol Appl Pharmacol, 153: 12-19
Darbre, P.D., Aljarrah, A., Miller, Coldham, Sauer, M.J., Pope, G.S. 2004. Concentrations of parabens in human breast tumours. J Appl Toxicol, 24: 5-13
Harvey, P.W. 2004. Discussion on concentrations of parabens in human breast tumours. J Appl Toxicol, 24, 307-310
Flower, C. 2004. Observations on the paper by Darbre et al. J Appl Toxicol, 24, 304-305
Boberg, J., Taxvig, C., Christiansen, S., Hass, U. 2010. Possible endocrine disrupting effects of parabens and their metabolites. Reproductive Toxicology, 30: 301-312
Ostrosky, E.A., Marcondes E.A.C., de Oliveira Nishikawa, S., Santos Lopes, P., Varca, G.H.C., et al. 2011. Rubus rosaefolius Extract as a Natural Preservative Candidate in Topical Formulations. AAPS PharmSciTech, 12: 732-737
Reisch, M.S., 2016. Restrictions on cosmetic preservatives ramp up. Chemical & Engineering News, 94: 18-20
I added my post to the Fabulous and Fun Life blogger link up party!