Sodium benzoate is a preservative that crops up on ingredient lists for skin care products. It is safe, works well enough and doesn’t give rise to many skin reactions.
I don’t think it is many formulators favourite though, because there are other preservatives that work better. Not every preservative works in every formulation and against every organism, and sodium benzoate is one that really needs a low pH to work well and even then isn’t enormously effective against all the microbes you’d like it to be. So it has its uses, but it isn’t especially versatile.
To a chemist though, the name is quite interesting. It is the salt of benzoic acid, and benzoic acid has played a key part in the development of organic chemistry. It was first derived from an asian shrub. Specifically, it was extracted the gum of the Styrax platanifolius. This had been used for centuries but was purified still further by a sixteenth century French chemist. He got it into a crystalline format from which he concluded, correctly, that it must therefore be a single compound. I think that this was the first pure natural compound to be identified.
The chemist’s name was Nostradamus. He’s still famous, not for his science but for some confusing predictions he made that continue to be talked about.
The chemistry of this compound was the focus of intense interest in the nineteenth century. It was studied by many chemists. But the prize for working out its structure was taken by Friedrich Wöhler and Justus von Liebig. These are two of the giants in the history of chemistry. Their work was later built on to create the discipline of organic chemistry.
There are quite a lot of cosmetic ingredients that are derivatives of benzoic acid, so you see ‘benz’ quite often on the backs of packs. It is a neat little history lesson.
There is an article I have seen posted on Facebook a couple of times that highlights the health risks of synthetic fragrance ingredients. I won’t link to it, but if I am seeing it there is a good chance you will have seen it too. The thesis it proposes is that synthetic chemicals in fragrances are toxic and might be dangerous to people who inhale them in public places, even if they aren’t actually wearing the fragrance themselves. Continue reading →
We’ve had elections recently in France, the US and the UK. We’ve had quite a lot of them in the UK actually. One of the things that happens a lot in politics is that partisans for one side or the other are keen to make out that their opponents have made a lot of mistakes. Given their terrible track record, you should boot them out and pick someone else instead is the argument. This is a convincing line if, and only if, the people who have got things wrong never learn from their errors. But the reality is that when things go wrong most of us look at the situation and see what we can learn to avoid getting it wrong again next time. I think this is true in every walk of life, and it is definitely true in the world of cosmetic formulation. The best lesson is getting something wrong and having to put it right. Good judgement is the result of experience. But experience is the result of bad judgement. You won’t get much right without first getting a lot of things wrong.
Silver can help make you beautiful as well as be used in jewellery
I don’t think that animal testing works the way some people commentating on the internet appear to think it works. This was brought home to me when I was asked a question about a new preservative material called silver citrate. It is one that might appeal to the lovers of natural because both silver and citrate sound safe and natural. We all know what silver is and so assume it is safe. Citric acid sounds like it comes from oranges so that sounds pretty safe too. But the person who was interested in it had read the material safety data sheet that came with it, and concluded that it had been tested on animals. For them this was a no no. Continue reading →
Hi, just wondering if you could give some information on the preservative Polyaminopropyl Biguanide? Apparently it was banned by the EU in January 2015 however appears to be still used in many beauty products including up to very recently Liz Earle’s cleanse and polish. Many thanks. Hello Sara,
I am not a big fan of Facebook. I find the interface a bit busy and confusing, and I haven’t really worked out who can actually see stuff when I post it. But it is a big platform so I feel obliged to got on it every now and again. I was on it recently and a side bar suggested I should join a group called “Get Methylisothiazolinone Removed From Products!”. It sounded interesting so I clicked on it and thought no more about it. Continue reading →
Preservatives in cosmetic products are a problem and will remain so until the way they are made and used changes significantly. I imagine someone somewhere is working on a project to create cosmetics in a small machine which you can programme with your favourite recipes. That would enable people to choose their own preservative option or to not use them at all and just make their personal care products fresh as needed. But until that technology becomes widespread preservatives are a necessity, and some people will have allergic reactions to them. Even the ones with a low propensity to cause allergic reactions, like the parabens and methylisothiazolinone, still cause plenty of people issues.? Continue reading →
There are an interesting couple of points in the comments thread on my blog post asking for MI not to become a scare story, from Suzanne. She has drawn my attention to a paper from 2012 that details developmental problems in tadpoles exposed to MI. She concludes from this that MI is potentially unsafe for humans as well and asks what the liability is for companies that continue to use it now that this risk has been identified. Continue reading →
There is a news story that L’Oréal have issued a product recall for their Ideal Moisture Dry and Sensitive Day Cream in Canada. The reason is that the level of MI in it is higher than Health Canada’s regulations allow. This is quite a rare event – big cosmetic companies are usually pretty good at following regulations. Unfortunately Google has not revealed the details of just how much over they were. But the product has been on the market for three years so there is a good chance that they have simply failed to keep up with the regulations and that the product was legal when formulated and launched. They have shifted just under 60,000 units. Continue reading →
Antioxidants get a lot of interest for the skin benefits, but for a cosmetic chemist they also have a rather more mundane use. If you are using natural ingredients in your products, and particularly some natural oils, you need to give some thought to the risks of oxidation of the product over its shelf life. Left to themselves many oils will go rancid, which gives them an unpleasant odour and often affects the colour. Consumers love natural products in principle, but aren’t keen on being presented with brown smelly ones. It is a shame to mess up a natural story by including chemical antioxidants, so what are the natural antioxidant alternatives? Continue reading →