Mineral Oil

Mineral oil is a bit of a boring chemical. It is only made of two atoms, carbon and hydrogen.  And they aren’t even combined in an interesting way – they are simply long chains of carbon atoms with hydrogen atoms attached to them.

Most chemical reactions take place via what we call functional groups – parts of molecules that can interact with functional groups on other molecules.  Mineral oil doesn’t have any and so is not very reactive.  It doesn’t even dissolve in water.

But being unreactive doesn’t make it useless.  One thing for which mineral oil is excellent is forming thin layers with good barrier properties.  And this is what makes it interesting for cosmetic scientists and dermatologists.  If you have dry skin, the chances are that it is due to the outer layer of your skin letting too much moisture escape.  A thin layer of mineral oil will slow down the loss of moisture and rehydrate your skin very quickly.  The lack of reactivity is a huge advantage here – skin reactions to mineral oil are almost unknown.

Mineral oil either on its own or as part of a formulation has been a mainstay of dry skin treatments since it first started becoming generally available around the time of the first world war.  It has also been found to be very helpful as a protective layer for the skin.  Baby’s bottoms exposed to nasty substances in their nappies (diapers) springs to mind.  But it is also handy for people whose occupations bring them into contact with skin damaging substances like for instance detergent in water.  If  you have a lot of washing up to do then gloves are the best option, but covering you hands with mineral oil will certainly help..

So are there any problems with mineral oil?  There are a few.  For a start the naming of the different grades could have been designed to confuse people.  The most familiar form of mineral oil is Vaseline.  Vaseline is a trademark for a particular brand, but a lot of people use it generically.  That particular grade of mineral oil is also known as petroleum jelly and petrolatum.  Lighter grades of mineral oil are usually referred to as liquid paraffin or light liquid paraffin.  Many baby oils are mainly light liquid paraffin.  The paraffin that used to be commonly sold in hardware shops to power paraffin heaters is a different chemical altogether.

The names of the various grades give away the origin of mineral oil as a  product of the petroleum industry.  It is one of many hundreds of materials distilled from crude oil.  I am not an expert on the petrochemical industry but the oil refining process is one that is capable of producing a huge range of materials.  I sometimes wonder if future generations will curse us for using so much of what came out of the ground as a fuel rather than finding more creative and valuable uses for it.

Some people don’t like mineral oil because it is a petrochemical.  This is perfectly true.  As an industry petrochemicals is about as non-environmentally sound as they come.   It is based on non-renewable resources and is effectively the root cause of global warming.   If we carry on the way we are going the petrochemical business is going to either ruin the planet’s climate, or if we run out of the stuff first, cause huge economic dislocation.

Globalisation is built on the back of cheap transport that opens up the most inaccessible places for economic exploitation. The mineral oil you apply to your skin is one small part of the damage the oil industry is doing to the planet.  It will, sooner or later,  be broken down by micro-organisms and will contribute to global warming.  The only counter-argument is that the scale of use of petrochemicals by the personal care industry is a microscopic fraction of what other industries, especially transport, use.   If you are driving a car then you are already funding the petrochemical industry directly by way way more than in your choice of what you put on your skin. But the plain fact is, mineral oil is definitely not a green material by any stretch of the imagination.

But there are many other objections raised to mineral oil.  I have pointed out in previous posts that Arbonne reps make criticism of mineral oil a key part of their sales pitch.  I have never fully understood what their problem with it is – it doesn’t seem to be the environmental one.  It seems to revolve around the idea that it blocks the skin and prevents it from breathing and carrying out its detox function.  The breathing issue is easily dealt with.  We don’t breathe through our skins.  The skin only has a limited role in detoxifying as well.  Most of our detoxification is carried out in the liver and toxins are generally disposed of in the urine.  Some toxins are removed in the sweat or sloughed off along with dead skin cells.  But you would have to absolutely smother yourself with mineral oil to seriously affect sweating.  And applying mineral oil is not going to stop dead skin cells being shed.  There is not the slightest suspicion in my mind that mineral oil has any direct harmful effect on the skin at all.

Other suggestions are that mineral oil contains harmful impurities.  The impurity cited is usually polyaromatic hydrocarbons, PAHs, which are carcinogenic.   There may be a reason for the origin of this story.  Mineral oils are used in some industrial applications and these grades can contain PAHs.  There have been occupational health issues with these industrial grades, and if you do a bit of googling you can find details of these.  One case is drilling fluids used on lathes in machine shops.  The levels of PAHs permitted have been reduced and synthetic alternatives have been developed so hopefully this problem is on the way out.  But in any case, it has no relevance to the mineral oil used in cosmetics.

Many people refer to the Skin Deep database for information about the safety of cosmetic ingredients.  This is a shame because it is usually highly misleading.  Lets have a look at what it says about mineral oil.  It describes it as being of low to moderate hazard depending on the usage, getting two scores.  It is either a 2 or a 4.  I can’t see any explanation for how you know which score is relevant.

The risks that are highlighted are cancer, allergies/immunotoxicity and organ system toxicity(non-reproductive)/occupational hazards.  I have no idea what they base these suggestions on.  There are references given but not to actual papers, so it is hard to see what the person assessing the material was thinking when they assigned a score.

The database also notes a 73% data gap.  I have no idea how that data gap is calculated.  73% is a very precise number so I suppose it comes from applying some kind of equation.  I couldn’t find an explanation on the Skin Deep website.  The most I got was ‘ The “data gap” rating is a measure of how much is unknown about an ingredient.’  I had gathered that much from the name.  I think a big part of it might be that whoever carried out this particular assessment was under the impression that mineral oil had not gone through the Cosmetic Ingredient Review process.  This isn’t actually true, it was assessed in 1984 (see References).  This would be an understandable error because the name in the title of the assessment is Paraffin.  This is an easy mistake to make if you have no idea of chemistry or the way scientific information is reported.  Fair enough, but maybe you shouldn’t be compiling a database about the hazards associated with chemicals.

But even so, the 73% data gap suggests that there is a lot we don’t know about mineral oil, no matter how it is calculated.  This is ridiculous because it is a very well known material indeed.  This can be illustrated on the Skin Deep database itself.  In the section called data gap it reads “1,165 studies in PubMed science library may include information on the toxicity of this chemical”.  When you follow the link you find yourself in the PubMed database with a filter applied with all the synonyms for mineral applied.  I have just done exactly that and it gives 1229 results.  The change in the numbers is not surprising – PubMed is continually being updated as new papers are published.

PubMed is a great resource for people who want to keep up with the literature on a particular subject.  Even just looking at the number of results begins to give you a feel about a subject.  For instance, a material referred to in over a thousand papers is obviously pretty well known.  But to get a real idea you do have to actually read the papers.  To say that there are a lot of papers about a material and that some of them may include information on its toxicity doesn’t really mean anything.  In fact I have just looked and not one of the first 20 results has the slightest relevance to the toxicity of mineral oil as used in cosmetics.  I wonder if anyone ever looks at that bit of the Skin Deep database and concludes that there are over a thousand studies showing that mineral oil is toxic.

To be fair, the precise wording used isn’t actually wrong.  There are a lot of papers and some of them might well be relevant to the assessment of toxicity.  But it is just as likely that they show it to be non-toxic as toxic.  A more meaningful wording would be ‘a list of papers that randomly mention mineral oil and which we haven’t read’.  But in any case, the idea that there is any kind of gap in the data available for this material is clearly untrue.   My advice is to ignore the Skin Deep database, although I am grateful to it for giving me some good laughs from time to time.

One persistent story about mineral oil is that it is banned in the European Union.  The origin of this story is elusive.  It is easily disproved simply by looking on the EU’s CosIng database. (see references.)

There are health risks associated with mineral oil in non-personal care uses.  The ability to form a film that effectively stops things crossing it is very helpful on dry skin but is a menace in other parts of the body.  It used to be used in some foodstuffs.  I can remember it being used on raisins.  I haven’t come across any specific studies that have demonstrated it, but in principle it is possible that mineral oil could block the absorbing of nutrients in the digestive system.  I am glad it is no longer used.  Another problem that is well documented is if it gets into the lungs.  This can happen in certain industrial processes and is a cause for concern for people whose business is occupational health.  I think what this illustrates well is that in order to understand the risks something poses you really do need to have some idea of how it is being used and what it can do.  Mineral oil is harmful in the lungs for exactly the same reason that it is beneficial on the skin.

So to sum up, mineral oil is perfectly safe and you will come to no harm using it either neat or in products.  It isn’t at all green, and it is a non-renewable material.  If that is important to you then you should consider avoiding it.  But if you have a patch of itchy dry skin, putting some kind of barrier onto it is a good move.  Are there good alternatives for it?  There certainly are and if you chose not to use mineral oil there are plenty of alternatives.  Indeed, in most cases more natural alternatives to mineral oil can work nearly as well and can often offer other benefits that you can’t get from mineral oil.  But mineral oil does have one unique feature that can be helpful for some people.  Because it is so inert you are very unlikely to have any kind of reaction to it.  If you have very sensitive skin, mineral oil might be the best choice.

References

http://www.ncbi.nlm.nih.gov/pubmed/20975563

EU CosIng database listing for Mineral Oil
http://ec.europa.eu/consumers/cosmetics/cosing/index.cfm?fuseaction=search.details_v2&id=35850

CIR Paraffin JACT 3(3):43-99, 1984

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From the UK, Colin Sanders has been a formulator of cosmetic and topical pharmaceuticals for 27 years. Over that time he has formulated nearly every category of product including shampoos, cosmetic skin creams, pharmaceutical skin creams, face masks, lip balms and so on. He has been an active member of the Society of Cosmetic Scientists since 1985 and in 1999 organised the first of the Formulate shows. His degree is in environmental science and he continues to take a keen interest in the impact of human activities on the planet. He regards himself as an environmental activist and all round green. When not in the lab, he writes a blog, Colin’s Beauty Pages with the intention of entertaining and hopefully informing users of cosmetic and personal care products with some insider insights, a bit of science and his own opinions.

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1. The Top 5 Myths About Mineral Oil:: Part 1
2. Myths About Mineral Oil:: Part 2
3. Natural or Not: The Story of a Mineral Oil Molecule