The chemistry of cosmetics

What's in the creams and powders that many of us put on our faces? Chemist and science writer John Emsley spoke to Katie Haylor. First up, Katie asked John, what's actually in the lipstick she puts on her lips?

John - Well, what you’re putting on is something like a wax or an oil mixed together with a colour or a dye with it. There are other components; there are about 20 components in some lipsticks. But basically, you’re doing what Ancient Egyptians did or Ancient Romans did, you want to highlight your lips with a deep red colour. In those first things they were using quite dangerous materials, they were using things like cinnabar, which is deep red but, of course, that’s a mercury compound. Today we use safe dyes and there’s no risk of you being affected by anything that you put on your lips.

Katie - Well, I’m very glad to hear it because I’ve just put some on. Now, I’ve just taken a sip of my cup of tea that I’ve got here in the studio and, unfortunately, I now have purple on the cup.

John - Oh, dear.

Katie - Is this supposed to happen?

John - Well, modern lipsticks were invented about a hundred years ago in America, and there were lots of faults with them to begin with. They were greasy; in cold weather they snapped, broke off; in hot weather they melted. They tended to pick up germs so they very quickly became infected. And, of course, people were using them because they were a simple way of applying colour to your lips.

Well, of course today, all of those problems have been solved. You’ve got a better range of colours. You can make it glossy, you can make it even sparkle by the things you put in it. And, of course today, we’d like to think of  the colours that you’re using are impermeable; in other words they won’t pass from your lips to whatever you touch.

I’m afraid to say I’d go round and look for something slightly better if I were you.

Katie - Now secondly, mascara. It’s a common thing to find in the makeup bag. This is put on my eyelashes. What is it?

John - Well again, mascara’s been around since ancient times. And the very first mascaras were using something called kohl. Now kohl again, there were minerals. There was an antimony mineral and there was a lead mineral that people used in those days, but you’re going back now to Ancient Egyptian times again.

Today, of course, they’re much safer. What you’ve got in a mascara is you want a wax base, and some of them actually use beeswax or carnauba wax and things like that. They tend to mix that with an oil so it’s much more flexible than just the simple wax. You also want something that keeps it permanently soft like glycerine, glycerol. You also want other components there, you obviously want a dark component. Today you’d tend to use carbon black or very black iron oxides.

You don’t want, of course, there to be infection in your mascara because you don’t want your eyes to become infected and you’ll need to protection against germs and things like that. So again, it’s a very complex mix but today, I think, they’re about as safe as it’s possible to be.

Katie - So John, another thing I’ve found in my makeup bag is a foundation liquid. What is foundation?

John - Well, the idea of foundation is protect the skin of the face and to mask blemishes. And so, lots of things could be included in foundation. Of course it depends, generally they’re different forms of iron oxides, so you can get the skin tone that you’re looking for. Very often you want to put a silicon layer on your skin because that protects it. It prevents water being absorbed from the skin so this can remain slightly plumper and, of course, it protects the skin against outside influences. So it’s a protective layer and it’s a disguise - that’s basically what a foundation is.

Katie - So John, now we’re in 2018 and a lot of people wear foundation but I’m guessing people have done this throughout history. So, as far as we know, when did people first start wearing foundation and how has it changed over time?

John - Again, we can trace that back to ancient times - mainly upper class women who used it. They didn’t want their skin to appear rugged. If you were an ordinary person and you worked outside a lot then, of course, you’d be exposed to UV, your skin would begin to look aged. You didn’t want to show you were such a person so you wanted a lighter skin, and very often what they were applying to their skin was very light pigments. Sometimes they even used arsenic trioxide, which was known as white arsenic in those days. And I believe Queen Elizabeth I was very partial to having her skin looking very white as proof that she was the upper class woman of the time.

Arsenic on the surface of the skin is not a threat. It does of course if it gets into your body. But even on the tiny amounts that you might have absorbed it wouldn’t do anything dangerous. Then of course  sometimes, if you took a little arsenic into your body then you’d get a red blush forming on your cheeks and, again, that was something that women took arsenic for at one time.

Katie - Oh dear! Okay, well I’m certainly not going to be doing that now. A slightly different one John, but what about deodorant and antiperspirant? It’s a cosmetic of sorts if we think about it trying to make us smell nice. What actually are these kind of sprays or roll-ons?

John - They're basically more important for men than women because men tend to smell. They tend to produce a lot more body odour than a woman does. Now you can stop that, you can prevent the bacteria that are producing these odours if you block the pores of you skin in the armpits which, of course, is where lots of the sweat is produced, and so you'd spray on something that would block them. Once it was aluminium salt but that fell out of favour, now it can often be a zirconium salt. You block those pores, you won’t produce as much sweat and so you can go off for the evening.

Katie - Deodorant antiperspirant blocking these pores, is it a good idea? Is it safe?

John - It wouldn’t be safe if you tried to do it all over your body, I mean there are people who’ve painted their body and died very quickly because you’ve blocked every pore. But it’s just these very profuse sweating glands under your arms that then produce these bacteria and then they give off very often sulphur based smells, which are quite strong and that all sweaty odour. And, of course, if you’re going out for the evening you’re going to mix with people, you don’t want people coming up to you and then backing away thinking oh god, what a pong! You want to give off a lovely come hither smell don’t you? Of course for women it’s just as important to do this as well. The other thing about deodorants is you can try and kill the bacteria that are causing it but, again, some of the, like triclosan, some of the very powerful antibacterial agents are now frowned upon. And so it’s perhaps best to shower every day and remain as fresh as you can.