Photo credit: Pixabay
I was pondering the topic for this article for quite a while. In my experience, inspiration comes when you least expect it, and usually from an unexpected source. One day I noticed that the back of my hand cream tube said “No phenoxyethanol” in large, inviting letters. And several thoughts went through my head, including: “Is that a good thing then?”, “Should I know about this already?” and “Is this another one of those ‘bad chemicals’ things?” So, naturally, I turned to the internet. From further investigation of both the hand cream packaging, and various searches online, I got the idea for this article. I want to share with you what I found, from the interesting science, to my horror at the public perception of science and finally to the moral of the story. So gather round and prepare yourselves for a rollercoaster ride of intrigue and conspiracy, with a small possibility of tears, as we explore my hand cream label (is that a bit of an anti-climax?).
On the front of this particular hand cream, it states proudly that it is full of polyphenols. This piqued my interest because it is common to find chemical names disguised, particularly in food products, because they are deemed ‘scary’ by consumers. Yet in this case, the chemical name is displayed with pride. That got me thinking about other cosmetic products, and it appears that in this consumer realm, chemical names can often be praised, usually because it makes it sound like the product works better (we are fickle creatures, are we not?). So I started Googling polyphenols and sure enough I got lots of sites praising their role as antioxidants and having anti-ageing abilities. But how much of this is marketing and buzz words, and how much is science?
Image credit: Kate Horner
It turns out that the evidence for polyphenols performing as antioxidants in vitro (i.e. in dishes/test tubes in the lab) is well established. An antioxidant is basically a molecule or substance that prevents the oxidation of other molecules. Why is this useful? Well, oxidation can create free radicals, which are molecules with an unpaired electron. These unpaired electrons make the molecule very reactive and can cause many other, sometimes unpleasant, reactions in the cells of your body. In some cases these can damage your DNA and cause cells to die. This plays a significant role in many cancers. For balance, however, I should point out that not all oxidation reactions are bad. In fact, reactive oxygen species are vital for cell signalling  and in homeostasis (the processes by which we regulate conditions in our body). So we should not be quick to make a devil out of all radicals. Likewise, evidence has even shown that antioxidant supplements can actually damage our health because some of these oxidation products have a positive impact on life span and our metabolism. 
So, ignoring the fact that there is some evidence that antioxidants aren’t always good for us, we should also consider whether in vitro tests showing antioxidant activity of polyphenols correlates to the same activity in vivo i.e. in the body. On this aspect, there is a mixture of findings really. For example, there is a study of a variety of emulsions of polyphenols applied to pig skin.  The research studied whether the polyphenols were able to penetrate the skin and also whether, once they had penetrated, they were released from the emulsion (they’re no good if they just stay in the cream). They found that indeed many phenolic compounds were able to penetrate the various layers of skin, though some types of emulsion were better than others. However, they are clear to point out that this in vitro study on pig skin is not necessarily directly comparable with in vivo tests on human skin and therefore more research needs to be undertaken. And therein lies the difference between marketing and good science. These scientists have shown a successful study, but are careful to highlight the limitations, whereas many marketing companies seem to hear “antioxidants fight cancer and permeate skin” and from there cause a storm of polyphenol converts. Sigh.
Now let us go to the other side of the hand cream tube and look at the things they proudly exclude from their product. The two offenders in this case are parabens and phenoxyethanol. Both are used in cosmetics as preservatives which keep germs at bay. This means the various products can be kept at home safely for much longer.
Image credit: Kate Horner
Let’s look first at parabens. These are esters of p-hydroxybenzoic acid and have a variety of alkyl groups attached to the ester end. A few years ago there was a lot of publicity about their safety (specifically their lack thereof). Just type ‘paraben’ into a search engine and you will see what I mean. Hundreds of websites advertising how nasty these chemicals are and how they must be avoided. They are touted as carcinogens, particularly causing breast cancer because it is said that they mimic oestrogen which is known to play a role in developing breast cancer. Sounds terrifying.
Now for a little perspective (and science)! First, the issue of oestrogenicity (a great word meaning how oestrogen-like something is). Oestrogen is a naturally-occurring (and people love that term) hormone present in both men and women, but is generally referred to as a female sex hormone. It has many vital functions ranging from controlling reproductive cycles to less exciting functions like protein regulation, fluid balance and coagulation. However, it also has a key role in growing breast cancers. Ironically, in men, oestrogen is sometimes used to treat prostate cancer- another reason not to vilify molecules. So where do parabens come in? Well, there is some evidence that these molecules can mimic oestrogen in the body. And since oestrogen is linked to cancer, we can (apparently) link parabens to cancer (though we don’t link them to any of the useful things oestrogen does…). That’s enough evidence for some people, but not for me. So I looked into the literature. The FDA points out some key research papers which show that, whilst parabens can mimic this hormone, they do so with a 10,000-100,000 fold lower activity than naturally occurring oestrogen. [5 and references therein] So perhaps if you want to be frightened of something, be frightened of your own hormones first.
The same FDA statement finds evidence that the most common parabens are safe in cosmetics up to a level of 25 %. To put that into context, generally parabens are only present at levels of between 0.01 % and 0.3 %.  I’m not exactly quaking in my boots just yet then. Further searching of the literature yields armfuls of safety research, all with similar findings containing terms like “genotoxicity…negative”, “…not indicative of carcinogenic potential”, “practically non-toxic by various routes of administration”, “non-mutagenic”, “practically non-irritating and non-sensitizing”, “…not carcinogenic, mutagenic or clastogenic…” and “Sensitization has occurred when… applied to damaged or broken skin”. [6-8] So overall, a pretty safe substance when used correctly. Bear in mind that moderation is the key to all things- in the wrong dose, even ‘safe’ things become toxic, for example, the lethal dose of chocolate for humans is around 22 lb, yet we still happily munch on it. And even water can easily kill when mistreated!
Image credit: Kate Horner
Finally- phenoxyethanol. Another preservative that many people are concerned about, and as a result, my hand cream is proudly phenoxyethanol free. Again, a quick web search will yield hosts of anti-phenoxyethanol material, most of which is the same. My absolute favourite, however, is a website about general lifestyle.  Here are a few great snippets:
”Technically, phenoxyethanol is an aromatic ether alcohol. This ingredient starts out as phenol, a toxic white crystalline powder that’s created from benzene (a known carcinogen) and then is treated with ethylene oxide (also a known carcinogen) and an alkali. Sounds dreamy.” Here we have thrown in lots of scary chemistry words like ether, alkali, benzene and ethylene oxide and we point out how toxic phenol is and its irrelevant relationship to benzene. Correct- phenol, on its own, with no attachments is toxic and causes burns. However, table salt is the child of a once-popular chemical weapon (chlorine gas) and a metal that bursts into flames in contact with air (sodium). Likewise, ethanol is the alcohol we frequently enjoy in drinks, but remove one carbon from the molecule, you get methanol and that causes blindness. Getting back to phenol, weren’t we just salivating over the prospect of polyphenols in an earlier paragraph? Let’s make up our minds! My head is starting to hurt.
”Phenoxyethanol is used in many all-natural beauty products touted as being “derived from grapefruits” ... It’s naturally occurring in green tea, but in cosmetics, it comes from a lab.” Do I need to point out what’s wrong with this? (See my earlier reference to a previous article I wrote.) Essentially- if the molecule is the same, is doesn’t matter where it comes from!! This is probably the most irritating misconception there is about science from my viewpoint. I can feel my blood pressure rising already so I will leave it at that. Calming breaths, Kate…
Image credit: Pixabay
I should probably also come to benzene’s defence since my PhD research revolved almost entirely around derivatives of the molecule. If you want to start getting picky about molecules that contain a benzene moiety, here are some you might like to avoid- paracetamol (which even has the phenol –OH group on it), aspirin, quinine (found in tonic water and a common medication for lupus and arthritis which also has analgesic, anti-malarial, anti-inflammatory and fever-reducing properties) and (with a few carbon substitutions) your own DNA! Point made.
And just in case you wondered about the literature, reference 10 says, “The experiments demonstrate that a distinct but weak sensitizing potency exists for [other substances]. Phenoxyethanol remained almost negative… Cases of phenoxyethanol contact allergy have been published hitherto only 4× in the medical literature.” So all those claims that this substance gave people allergies are not yet supported by science. Also, bear in mind, all kinds of ‘natural’ things can cause allergies too.
I think the key point here is perspective. Moderation and perspective. These two qualities will rarely steer you wrong in my experience. Perhaps it will turn out that some of these molecules have a toxic effect one day. However, bear in mind that everything is toxic in the right amount or with the right administration. We are so terrified of cancer in modern times that as soon as something is vaguely linked to it, we panic. Our food contains carcinogens, our drinks contain them, even the air we breathe in, but many of these are naturally produced (so don’t blame evil scientists) and many have positive effects as well. Furthermore, be careful about ruling something out of your life before you have explored both sides of the story, and always try to keep things in perspective.