0:00:00 > 0:00:03This series is about all the stuff we just can't live without.
0:00:03 > 0:00:08Whether it's products for personal hygiene, home cleaning or DIY,
0:00:08 > 0:00:11it's about those bottles, cans, sprays, jars and tubes
0:00:11 > 0:00:15crammed into our cupboards, drawers, handbags, sheds and cars.
0:00:15 > 0:00:20I want to know what's in all this stuff!
0:00:20 > 0:00:25I'm Jane Moore. I'm out to decode the magic hidden in my supermarket shopping list,
0:00:25 > 0:00:30to throw away the packaging and get to the brilliant wonderstuff inside.
0:00:30 > 0:00:34'My journey has seen me stumbling around in the dark...'
0:00:34 > 0:00:36It's like Raiders of the Lost Ark!
0:00:36 > 0:00:38'..and facing my worst phobias.'
0:00:38 > 0:00:40Eugh!
0:00:40 > 0:00:44'But ultimately rewarded with some genius in action.'
0:00:44 > 0:00:47That is absolutely astonishing!
0:00:47 > 0:00:50Once finished, I'm expecting to go down the supermarket aisle
0:00:50 > 0:00:53with a new-found confidence in what I'm looking for,
0:00:53 > 0:00:57having discovered what really does the job.
0:01:16 > 0:01:21My task is to hunt down the unexpected wonderstuff in our lives.
0:01:21 > 0:01:26Those genuinely clever substances lurking in the stuff we use every day.
0:01:28 > 0:01:31This time, I'm out to find the hidden brilliance
0:01:31 > 0:01:35behind three of the things most of us slap on each morning.
0:01:35 > 0:01:39Face cream, antiperspirant and sun screen.
0:01:42 > 0:01:46I have to say, I've got a bit of a personal motive on this new leg of my quest.
0:01:46 > 0:01:49At my age, I need all the moisturising I can get!
0:01:49 > 0:01:51Not only do I get to test them,
0:01:51 > 0:01:56but also I've been promised we'll be learning the identity of its magic bullet.
0:01:56 > 0:02:00Later, my materials maestro, Mark Miodownik,
0:02:00 > 0:02:03does a demo which really is the pits!
0:02:03 > 0:02:06I wouldn't like to meet a man who sweated that much!
0:02:08 > 0:02:12But first on my shopping list is a little bottle
0:02:12 > 0:02:15that we Brits secretly hope we're going to need lots of.
0:02:17 > 0:02:18Sun screen.
0:02:24 > 0:02:29When I was growing up, suntan lotion seemed to be sold as glorified cooking oil,
0:02:29 > 0:02:31designed to roast you quickly to a nice leathery brown.
0:02:34 > 0:02:36But now that we know more about sun damage,
0:02:36 > 0:02:40we count on products that use science to guard us from over-exposure.
0:02:40 > 0:02:45But how do we know whether the ingredients in these products give us the right protection?
0:02:45 > 0:02:48And if so, what's the wonderstuff that's doing it?
0:02:51 > 0:02:55I'm heading to the HQ of one of the UK's biggest developers and sellers
0:02:55 > 0:02:57of sun protection products, to find out.
0:02:57 > 0:03:01Blimey, it's like arriving at the Swiss frontier!
0:03:01 > 0:03:03Which way now?
0:03:05 > 0:03:08This place is absolutely huge!
0:03:08 > 0:03:10It's like a town in itself!
0:03:13 > 0:03:19This is where Boots develops its potions and puts them to the test on human guinea pigs.
0:03:19 > 0:03:24So I've come to the perfect place to shed some light on how sun creams work.
0:03:24 > 0:03:29Skin specialist Ian Marlow has got the kit that can tell me whether I've been giving my skin
0:03:29 > 0:03:31the right sun protection.
0:03:31 > 0:03:34When I read a bottle I'm thinking of the words SPF factor,
0:03:34 > 0:03:38- or SPF - the F is the factor, isn't it?- It is, yes.
0:03:38 > 0:03:43It's the sun protection factor. That's been the standard claim on some products for many years.
0:03:43 > 0:03:49Sun protection factor is primarily measuring the ability of a product to protect against burning.
0:03:49 > 0:03:52Burning is caused mainly by UVB rays.
0:03:52 > 0:03:57We all know that we need some sunlight to get our dose of Vitamin D.
0:03:57 > 0:04:00But too much ultraviolet light will harm us.
0:04:00 > 0:04:03Apparently, there are two different types of UV light.
0:04:03 > 0:04:06UV-B, which burns the skin's surface,
0:04:06 > 0:04:08and the equally dangerous UV-A.
0:04:09 > 0:04:1395% of all the UV light that hits our skin is actually UV-A.
0:04:13 > 0:04:16UV-A works much more indirectly
0:04:16 > 0:04:19by attacking molecules in the skin
0:04:19 > 0:04:23that we know can go on then and cause other damage to DNA
0:04:23 > 0:04:28and also result in a break-down of the collagen and elastin in the skin
0:04:28 > 0:04:32that leads to that loss of firmness and more wrinkling in the skin.
0:04:32 > 0:04:38Unluckily for me, Ian has a machine that can measure the effects of this invisible UV-A.
0:04:38 > 0:04:42In the interests of science, and because it's in my contract,
0:04:42 > 0:04:44I volunteer myself for a check-up!
0:04:46 > 0:04:50- You need to take your make-up off before we start.- Now he tells me!
0:04:50 > 0:04:54It's like asking me to run naked round Trafalgar Square,
0:04:54 > 0:04:57taking my make-up off on national television!
0:04:57 > 0:05:00'I hope you're happy, Mr BBC Commissioner!'
0:05:00 > 0:05:04I'm not taking my eye make-up off for anyone!
0:05:05 > 0:05:06Right, there we go.
0:05:07 > 0:05:09'My face is scanned with ultra-violet light.'
0:05:13 > 0:05:15I'm still alive!
0:05:15 > 0:05:17'The images are processed
0:05:17 > 0:05:22'to reveal exactly how much UV damage I've subjected my skin to over the years.
0:05:22 > 0:05:27'But I'm not worried. Surely my use of sun cream has done its job, right?
0:05:27 > 0:05:29'Wrong.'
0:05:29 > 0:05:32What we can see here, all the dark spots on the image
0:05:32 > 0:05:37are actually areas where your skin has responded to ultraviolet light
0:05:37 > 0:05:38and has produced melanin.
0:05:38 > 0:05:43Particularly, we often find this when we look at the nose or the forehead
0:05:43 > 0:05:47you can see a higher density of dark spots.
0:05:47 > 0:05:53- That indicates that your nose and forehead has had insufficient coverage...- I'm speechless!
0:05:53 > 0:06:01..over the years and we know that that correlates closely to lines and wrinkles in later years.
0:06:01 > 0:06:02That's awful!
0:06:02 > 0:06:05'Thanks, Ian. Do you have any good news for me today?'
0:06:05 > 0:06:11What this machine also allows us to do is compare you to people of a similar age.
0:06:11 > 0:06:14Here we can see you're at the 33rd percentile.
0:06:14 > 0:06:16So you're within that middle range.
0:06:16 > 0:06:19- Am I below average? - A bit below average.
0:06:19 > 0:06:21Am I better off than them, or worse?
0:06:21 > 0:06:23Worse, I'm afraid!
0:06:24 > 0:06:26Oh, God!
0:06:26 > 0:06:28I'm never coming here again!
0:06:28 > 0:06:31I've had too many holidays.
0:06:31 > 0:06:38'But what's puzzling me is I've been so careful to use sun cream when I'm on those sunny holidays.'
0:06:39 > 0:06:44What this really emphasises now is it's not just about protecting your skin
0:06:44 > 0:06:46from the sun when you go on holiday.
0:06:46 > 0:06:53- It's about protecting it all year round.- But I shouldn't have to wear something in November, should I?
0:06:53 > 0:07:00- About a quarter of the amount of incident UV-A hits your skin between October and May.- Really?
0:07:00 > 0:07:03That's it. Enough humiliation for one day.
0:07:03 > 0:07:07So where's the wonderstuff that's going to save my skin?
0:07:08 > 0:07:11These clever people combine a variety of different UV blocking
0:07:11 > 0:07:13or reflecting substances,
0:07:13 > 0:07:15each one doing a different job.
0:07:15 > 0:07:18I'm told that three of these cutting-edge ingredients
0:07:18 > 0:07:22do the job of stopping UV-B burning our skin.
0:07:22 > 0:07:28But there's one more that's really crucial because it blocks out the ageing UV-A. Sounds good!
0:07:28 > 0:07:32That magic ingredient is...
0:07:32 > 0:07:37How easy is that to say? B-otty... No, forgotten it already!
0:07:37 > 0:07:41It still says on our packs. But if you got a pack in the US,
0:07:41 > 0:07:44it would be given a snappier title of avobenzone.
0:07:44 > 0:07:46That'll do for me!
0:07:47 > 0:07:50The green line shows just how significantly
0:07:50 > 0:07:56avobenzone blocks out those nasty deep-down and damaging UV-A rays.
0:07:57 > 0:08:02All of that cleverness wrapped up in one cream. Pretty impressive.
0:08:02 > 0:08:08'Ian decides that to see just how effective a sun cream with avobenzene really can be,
0:08:08 > 0:08:12'it's back to the ultra-violet face scanning thingy machine.
0:08:12 > 0:08:14'But this time, it's only good news.
0:08:14 > 0:08:18'With half my face creamed up and half just bare skin,
0:08:18 > 0:08:20'the difference is striking.
0:08:20 > 0:08:25'The dark half with avobenzone covering me up
0:08:25 > 0:08:27'is absorbing almost all the UV light
0:08:27 > 0:08:29'before it gets to my skin.'
0:08:29 > 0:08:32It's clever stuff, isn't it?
0:08:32 > 0:08:34Ziggy Stardust, there I am!
0:08:36 > 0:08:41Medical advice varies on whether we should be slapping on sun screen all year round.
0:08:41 > 0:08:44But if avobenzone helps to reduce wrinkles,
0:08:44 > 0:08:47then it makes it onto my wonderstuff list.
0:08:48 > 0:08:51While other parts of sun cream take care of the burning,
0:08:51 > 0:08:55this invaluable little chemical can protect us from premature ageing.
0:08:55 > 0:08:59It turns up in lipsticks, foundations and skin creams.
0:08:59 > 0:09:04I'm suddenly feeling less guilty about all my cosmetic clutter!
0:09:06 > 0:09:11'So, after that wake-up call, I'm anxious to find out more about my skin.
0:09:11 > 0:09:15'And if there's anything else I should be rubbing in to help look after it.
0:09:15 > 0:09:21'Mark Miodownik, my friendly materials expert, is on hand to help.
0:09:21 > 0:09:26'His first gift for me is a surprising close-up view of my skin. Not keen on this!'
0:09:26 > 0:09:31I know this is a laptop, but what's with the travel hairdryer?
0:09:31 > 0:09:35It looks like one, doesn't it, but it's a microscope.
0:09:35 > 0:09:39You can zoom in to anything. So I can have a look at your skin.
0:09:39 > 0:09:41- Don't panic! There we go. - Oh, my word!
0:09:41 > 0:09:46- That's you under the microscope. You look amazing!- It looks like a dry river bed!
0:09:46 > 0:09:50No, I've looked at a lot of people's skin and that's very good.
0:09:50 > 0:09:53- Is it?- The structure isn't kind of disturbed.
0:09:53 > 0:09:57- It's got a very good colour. - I like you!
0:09:57 > 0:10:02'Mark tells me that the thickness of our skin varies from around 4mm on our palms
0:10:02 > 0:10:04to half a millimetre on our eyelids.
0:10:04 > 0:10:09We can look on your face. This is going to be completely different.
0:10:09 > 0:10:11Can you see down? Isn't that wonderful?
0:10:11 > 0:10:15- It's glittery!- That's your make-up. Nice glittery make-up!
0:10:15 > 0:10:18It's your best asset, your skin. It's 16% of your body weight.
0:10:18 > 0:10:20- The biggest organ in the body.- Yes.
0:10:20 > 0:10:25It allows you to cool and also protects you from losing too much water.
0:10:25 > 0:10:31Your skin is your most precious asset. It protects from bacteria, viruses, everything.
0:10:31 > 0:10:33It's your first barrier against the world.
0:10:33 > 0:10:36Keeping it in good nick is the thing to do!
0:10:36 > 0:10:39'Phew! I didn't come off that too badly.
0:10:39 > 0:10:42'Or maybe Mark's just being nice!
0:10:42 > 0:10:47'But is there a wonderstuff that can keep my skin barrier in peak condition?
0:10:47 > 0:10:52'As a nation, we slap on £3 billion-worth a year
0:10:52 > 0:10:54'of something that we think will do the trick -
0:10:54 > 0:10:56'moisturiser.
0:10:56 > 0:10:58'So what's in it, and does it work?
0:11:02 > 0:11:06'To find out if there is something in moisturisers that makes them worth it,
0:11:06 > 0:11:11'I'm going to meet Dr Mike Bell, who's an expert on the subject.'
0:11:11 > 0:11:13Tell me, what is dry skin?
0:11:13 > 0:11:15What's happening?
0:11:15 > 0:11:18I think of skin as a bit like play putty.
0:11:18 > 0:11:23When water's within play putty, it looks very much like this.
0:11:23 > 0:11:27Everybody's familiar with that, with children playing with it.
0:11:27 > 0:11:29You can mould it. It's flexible.
0:11:29 > 0:11:31That's all because of the water in it.
0:11:31 > 0:11:36- But as soon as it dries out, if the children leave the tops off...- Next day in my house.
0:11:36 > 0:11:39..it becomes a bit like this.
0:11:39 > 0:11:43It can be torn apart, it cracks, and actually, it's fit for the bin.
0:11:43 > 0:11:46That's exactly what happens with dry skin.
0:11:46 > 0:11:51That's all because of the water content in the outer layer of skin called the stratum corneum.
0:11:51 > 0:11:55It's about as thick as a piece of paper. Literally no thicker than that.
0:11:55 > 0:12:00The water content in this determines how dry or not dry the skin is.
0:12:00 > 0:12:03'This paper-thin protective outer layer
0:12:03 > 0:12:06'is apparently the main barrier to help my skin drying out.
0:12:06 > 0:12:08'And there's a test
0:12:08 > 0:12:12'to show me exactly how important it is to keep this layer of skin healthy.
0:12:12 > 0:12:18'First, Mike's assistant Clara measures the rate my skin is currently using water.'
0:12:18 > 0:12:20Your skin in its resting condition
0:12:20 > 0:12:25probably loses about 100 to 150 ml of water each day.
0:12:25 > 0:12:29Because outside, it's much drier than inside the skin.
0:12:31 > 0:12:36'This graph is showing the catchily-named "trans-epidermal water loss".'
0:12:38 > 0:12:41What we're looking for is when it actually plateaus.
0:12:41 > 0:12:44That's the resting level of water leaving your skin.
0:12:44 > 0:12:49'That done, it's time to see how much water I lose when my skin barrier is damaged.
0:12:49 > 0:12:50'Uh-oh!'
0:12:50 > 0:12:54What we're doing here is stripping off ten layers of your skin.
0:12:54 > 0:12:56- Ten layers?!- Ten layers.
0:12:56 > 0:12:58Ow!
0:12:58 > 0:13:00It's painless, really!
0:13:00 > 0:13:03What's coming off? Like dead cells?
0:13:03 > 0:13:05Dead skin cells.
0:13:05 > 0:13:08But basically, you're taking off the stratum corneum.
0:13:08 > 0:13:12Some of the layers that are so important for the barrier function of your skin.
0:13:12 > 0:13:18- Will I get it back?- You will get it back. It'll take a few days for that bit to repair completely.
0:13:18 > 0:13:19But it's quite quick.
0:13:19 > 0:13:21Do you get pleasure out of this, Clara?
0:13:21 > 0:13:24- I try not to!- I worry about people like you!
0:13:25 > 0:13:29'Then the probe is applied again and the results are in.'
0:13:30 > 0:13:33And now the reading is at about 11.3.
0:13:33 > 0:13:37Previously, it was at about 8.9.
0:13:37 > 0:13:40So the water loss has been increased from your skin.
0:13:40 > 0:13:44'Damaging our precious outer barrier means the skin below
0:13:44 > 0:13:47'will dry out and fall apart quicker. Not what we want.
0:13:47 > 0:13:53'So now I know how precious my stratum corneum skin barrier is,
0:13:53 > 0:13:55'how best to keep it strong and healthy?'
0:13:55 > 0:14:01Lots of supermodels in particular swear by drinking two litres of water a day,
0:14:01 > 0:14:04saying it makes their skin look better. Is it true?
0:14:04 > 0:14:07Absolutely, because the water comes from your blood vessels.
0:14:07 > 0:14:12So if you're dehydrated, you have less water coming from those blood vessels
0:14:12 > 0:14:14that then percolates through the skin.
0:14:14 > 0:14:17So yes, you need to be hydrated yourself.
0:14:17 > 0:14:20'But well as hydrating your skin from the inside,
0:14:20 > 0:14:23'I'm told there's a quicker way to hold on to that water.
0:14:23 > 0:14:25'Enter moisturiser.'
0:14:25 > 0:14:30What a moisturiser can do, by putting back in that moisture into the top layers of skin
0:14:30 > 0:14:33and actually cementing it better,
0:14:33 > 0:14:36it means that the skin maintains a better barrier.
0:14:36 > 0:14:42'I know Mike's bound to extol the virtues of something he's dedicated to developing here at Boots,
0:14:42 > 0:14:48'but he promises that once I've seen some moisturiser made from scratch, I'll understand what the fuss is.
0:14:49 > 0:14:54'First into the mix are oily emollients like soft paraffin wax.'
0:14:54 > 0:15:01The wax is important to giving the skin feel a richness to it. It conditions and softens the skin.
0:15:01 > 0:15:06The aim of emollients is to try and hide some of the stickiness or greasiness.
0:15:06 > 0:15:08'Then there's an emulsifier.'
0:15:08 > 0:15:13It allows this emulsion, as we call it, to form.
0:15:13 > 0:15:16Oil droplets dispersed in a water phase.
0:15:16 > 0:15:19'But here comes the truly magic ingredient!
0:15:19 > 0:15:23'A colourless, odourless, viscous and devilishly clever liquid
0:15:23 > 0:15:25'added to the water, glycerine.'
0:15:25 > 0:15:29As in glycerine that I make icing with?
0:15:29 > 0:15:33Absolutely. It has similar properties used in cosmetics as in cooking.
0:15:33 > 0:15:35It's a fantastic water binder.
0:15:35 > 0:15:41'Mix all the ingredients together and you have a basic yet highly effective moisturiser.
0:15:41 > 0:15:45'But it's the glycerine that's grabbed my attention.'
0:15:45 > 0:15:50The glycerine in the moisturiser is what would form that sort of barrier
0:15:50 > 0:15:53- to stop the water releasing as quickly?- Absolutely.
0:15:53 > 0:15:57So it's probably the most important ingredient for a moisturiser
0:15:57 > 0:16:00because it will bind water at the surface of the skin.
0:16:01 > 0:16:04'OK. This I have to see!'
0:16:04 > 0:16:09So here we have a weighing balance. We've got some glycerine here.
0:16:09 > 0:16:14I'm going to pour this glycerine, a certain amount, into the balance.
0:16:20 > 0:16:24As you can see, it's actually increasing in mass
0:16:24 > 0:16:28and the only way it can do that is by grabbing water molecules
0:16:28 > 0:16:30as they pass over the surface of the glycerine.
0:16:30 > 0:16:33Shows how fantastic a humectant it is.
0:16:33 > 0:16:37Humectant means grabbing humidity? Is that where it comes from?
0:16:37 > 0:16:41Grabbing water and holding on to it. That's what glycerine does.
0:16:41 > 0:16:44It's important that when the conditions get drier,
0:16:44 > 0:16:46and the humidity gets lower,
0:16:46 > 0:16:49it's still able to hold on to that moisture.
0:16:49 > 0:16:52How is it actually doing that?
0:16:52 > 0:16:55Well, glycerine has a quite simple structure
0:16:55 > 0:16:59which enables it to form bonds, links, with water.
0:16:59 > 0:17:00So that's all it does.
0:17:00 > 0:17:04It forms bonds with water to grab it to its structure.
0:17:04 > 0:17:08- Like a spider in a web?- Absolutely. That's a good analogy.
0:17:08 > 0:17:14'And this amazing chemical sponge is also highly abundant.'
0:17:14 > 0:17:17Where does it come from originally?
0:17:17 > 0:17:19This is vegetable-derived glycerine.
0:17:19 > 0:17:21It comes from fatty acids and lipids
0:17:21 > 0:17:24in vegetables, in plants.
0:17:24 > 0:17:28It's a by-product of the soap industry as well in making soap and candles.
0:17:28 > 0:17:32By chance, they discovered that was an end product.
0:17:32 > 0:17:35It has many, many applications, thankfully for us!
0:17:35 > 0:17:41- So glycerine is the key ingredient for anyone making a moisturiser? - It is.
0:17:41 > 0:17:45In fact, it's the gold standard humectant in the cosmetic industry.
0:17:45 > 0:17:48I had absolutely no idea about this.
0:17:48 > 0:17:50I'm absolutely amazed by it,
0:17:50 > 0:17:54that just a clear liquid can do this amazing thing.
0:17:54 > 0:17:58I'm going to go and bathe in a bath of glycerine now!
0:17:58 > 0:18:01I'll look like the incredible shiny woman!
0:18:02 > 0:18:06'Glycerine, also called glycerol, is derived from fat -
0:18:06 > 0:18:08any kind of fat will do.
0:18:08 > 0:18:13It was discovered by accident by the German/Swedish chemist Scheele in 1779.
0:18:13 > 0:18:18Its sweet taste and low toxicity make it ideal for use in the food industry
0:18:18 > 0:18:21where it also goes by the name E422.
0:18:21 > 0:18:25Glycerine is incredibly useful and has virtually no side-effects
0:18:25 > 0:18:27unless it's combined with acid
0:18:27 > 0:18:30to form the explosive nitro-glycerine.
0:18:30 > 0:18:34When it comes to keeping up appearances, moisture can also be a problem
0:18:34 > 0:18:36if you have too much of it.
0:18:36 > 0:18:40I'm talking about the potentially embarrassing matter of sweat.
0:18:40 > 0:18:43I want to know why is it that we do sweat
0:18:43 > 0:18:47and also what's the magic ingredient in antiperspirant
0:18:47 > 0:18:50that helps us to keep it under control.
0:18:56 > 0:19:00I've come to Leeds University to sniff out Dr Mark Hetherington,
0:19:00 > 0:19:04a physiologist with his own special climate chamber.
0:19:04 > 0:19:11He runs tests in controlled temperature and humidity to learn the ways in which people sweat
0:19:11 > 0:19:13and to give clues as to what we can do about it.
0:19:13 > 0:19:17There are lots of differences in the ways individuals sweat.
0:19:17 > 0:19:24Fit people sweat more than unfit, and those who are acclimatised sweat more than people who aren't.
0:19:24 > 0:19:27The average person has got three million sweat glands.
0:19:27 > 0:19:32Each of them produces a solution which it takes from the body's fluids
0:19:32 > 0:19:35and secretes it onto the skin from where it evaporates.
0:19:35 > 0:19:38It's the evaporation of sweat from the skin that cools you.
0:19:41 > 0:19:44'So we need all those sweat glands to keep us cool.
0:19:44 > 0:19:50'So why do some parts of our bodies become more of an embarrassment than others?'
0:19:50 > 0:19:54Where do we sweat the most? I'd think it would be under the armpit?
0:19:54 > 0:19:59Interestingly, there are more sweat glands per square centimetre of skin
0:19:59 > 0:20:02on the palms of the hands and soles of the feet.
0:20:02 > 0:20:06But probably when you're hot and sweating to cool yourself,
0:20:06 > 0:20:11the majority of sweat will be produced in the chest, back, forehead and face.
0:20:11 > 0:20:15'Hang on, if I pump out more sweat from my face,
0:20:15 > 0:20:19'why do I associate the iffy smell with armpits?'
0:20:19 > 0:20:24Because the sweat gets trapped in the armpit and can't evaporate. It accumulates
0:20:24 > 0:20:26which is why you get wet armpits.
0:20:26 > 0:20:30It's also partly because we have a different type of sweat gland in the armpit
0:20:30 > 0:20:34to the skin on the rest of the body, called an apocrine sweat gland,
0:20:34 > 0:20:38which tends to be activated more by emotion and fear
0:20:38 > 0:20:41so if you've got a job interview and you get sweaty armpits,
0:20:41 > 0:20:43it's those sweat glands that are active.
0:20:43 > 0:20:48It's thought that that type of sweat contains more protein from the body
0:20:48 > 0:20:50so it's not the sweat itself that smells,
0:20:50 > 0:20:53it's the product of a bacterial breakdown.
0:20:53 > 0:20:59It's that bacterial breakdown that causes the odours associated with smelly armpits.
0:20:59 > 0:21:02'So it's healthy to allow the sweat from most parts of our body
0:21:02 > 0:21:05'to evaporate into the air to cool us.
0:21:05 > 0:21:09'A squirt of deodorant, basically just perfume, won't interfere with that.
0:21:09 > 0:21:13'But when it comes to armpits and their potentially embarrassing smell,
0:21:13 > 0:21:18'we need something much cleverer to stop us sweating altogether. Antiperspirant.
0:21:20 > 0:21:26'So, how does it do that? As ever, I'm turning to trusty old Mark
0:21:26 > 0:21:28'who, aside from his other skills,
0:21:28 > 0:21:33'reckons he can build a makeshift model of a giant armpit in action.
0:21:33 > 0:21:35'This I have to see!'
0:21:35 > 0:21:40So here we have a piece of your skin, perhaps under your arm.
0:21:40 > 0:21:42You've heard about my skin?
0:21:42 > 0:21:47No, come on, it's very soft and smooth and clean.
0:21:47 > 0:21:50And here's the gland, maybe.
0:21:50 > 0:21:52This has got some water in it.
0:21:52 > 0:21:54Put that there.
0:21:54 > 0:21:55- OK?- Right.
0:21:55 > 0:21:58Then it gets hot. You're in the sauna, maybe,
0:21:58 > 0:22:00or on a tropical island, preferably.
0:22:00 > 0:22:04- And out you sweat.- Right, OK.
0:22:04 > 0:22:07There's the sweating.
0:22:07 > 0:22:10Then the idea is that it evaporates and you get cool.
0:22:10 > 0:22:13But what if too much comes out?
0:22:13 > 0:22:15And you're, er...
0:22:15 > 0:22:17And you get wet!
0:22:17 > 0:22:21- Then you feel uncomfortable. - I wouldn't like to meet a man who sweated that much!
0:22:21 > 0:22:24This is obviously the problem.
0:22:24 > 0:22:27So from a simple-minded point of view,
0:22:27 > 0:22:32if you put something on this surface that could mop up this sweat,
0:22:32 > 0:22:36and could attract it so it was less wet and became solid,
0:22:36 > 0:22:40then that would perhaps be the solution.
0:22:40 > 0:22:45With an antiperspirant, some of the active ingredients do that.
0:22:45 > 0:22:48So we'll put some on here. This is a gelling agent.
0:22:48 > 0:22:52It's not what's actually in antiperspirant, but works the same way.
0:22:52 > 0:22:58- It scavenges water and almost makes it into a solid. It's this gel. - Oh, look at that.
0:22:58 > 0:23:01- It's like a little sugar sweetie. - Yeah.
0:23:01 > 0:23:04But of course there's still more water to come out.
0:23:04 > 0:23:07That's not going to solve our problem.
0:23:07 > 0:23:13You have to keep putting more on. So we want this gland to stop being so productive.
0:23:13 > 0:23:16'According to Mark, the really clever trick
0:23:16 > 0:23:20antiperspirants pull is by working their way inside our pores.'
0:23:20 > 0:23:25All that sweat is becoming not so liquid any more.
0:23:25 > 0:23:27It looks like a gel which is semi-solid.
0:23:27 > 0:23:31- Then if I do that... - Ah!- It's not going anywhere.
0:23:31 > 0:23:37So that's what happens inside the sweat gland when we put antiperspirant on?
0:23:37 > 0:23:41Again, it's not quite clear whether it's happening inside the gland
0:23:41 > 0:23:43or whether it's just a plug.
0:23:43 > 0:23:46- But it works.- It works.
0:23:46 > 0:23:51'OK, I've got the point that there's something in antiperspirants
0:23:51 > 0:23:56'that plugs up the glands in our armpits and stops them from producing more sweat.
0:23:56 > 0:24:01'So, what sort of wonderstuff is performing this magic trick?
0:24:01 > 0:24:03'And where does it come from?'
0:24:06 > 0:24:10It seems that the answer lies in a rather unusual place.
0:24:10 > 0:24:14So, on the trail of the active ingredient in antiperspirant,
0:24:14 > 0:24:19I've come to meet a man in the know at a quarry in deepest Yorkshire.
0:24:22 > 0:24:27'Jack Walky is a chemist whose job it is to formulate ingredients for popular toiletries.'
0:24:27 > 0:24:32Well, Jack, you really know how to treat a girl. Why am I in a quarry?
0:24:32 > 0:24:38We're here to talk about a material that's the most abundant metal on the surface of the planet.
0:24:38 > 0:24:40An extremely useful material, aluminium.
0:24:40 > 0:24:42Ah!
0:24:42 > 0:24:47'Jack tells me that aluminium, which is present in the rocks and soil all around us,
0:24:47 > 0:24:52has also been one of the key ingredients in antiperspirants for over 100 years.
0:24:52 > 0:24:57In the late 1800s, particularly under the hot lights from the stage,
0:24:57 > 0:25:04actors and actresses were using different products to reduce perspiration.
0:25:04 > 0:25:08One of the ones they came up with was aluminium chloride,
0:25:08 > 0:25:10which was a great antiperspirant,
0:25:10 > 0:25:14but quite irritant and quite damaging to clothing.
0:25:14 > 0:25:21'It wasn't until the 1940s that less acidic versions based on aluminium chloride were produced,
0:25:21 > 0:25:23'such as the very popular Stopette.'
0:25:23 > 0:25:28Then developments moved along and we got aluminium chlorohydrate that we know today.
0:25:28 > 0:25:33Aluminium chlorohydrate that we know today is the basis of most antiperspirants in the West.
0:25:33 > 0:25:39'It's amazing to think that metal dug up from the ground can be mixed with hydrochloric acid
0:25:39 > 0:25:41'to give aluminium chlorohydrate,
0:25:41 > 0:25:45'a substance we all rely on to keep B.O at bay.
0:25:45 > 0:25:49'It's the wonderstuff that manages the balancing act of being a sweat-stopper
0:25:49 > 0:25:52'that's still gentle on the skin.'
0:25:53 > 0:25:58Aluminium chlorohydrate and its close cousins have been gracing our armpits for decades.
0:25:58 > 0:26:02They're still the only substances that do the job effectively.
0:26:02 > 0:26:06And contrary to a widely-held belief, there's no scientific evidence
0:26:06 > 0:26:09that these compounds are linked to breast cancer.
0:26:13 > 0:26:17My investigation into the stuff that we slather on in the name of beauty
0:26:17 > 0:26:19has exposed some surprising truths.
0:26:19 > 0:26:23Not least have I failed to protect my skin from ultra-violet rays,
0:26:23 > 0:26:29but also that something as simple as the glycerine my granny used for baking
0:26:29 > 0:26:33is still the number one substance for moisturising my skin.
0:26:34 > 0:26:40But for me, the biggest revelation is that despite the dizzying array of antiperspirants on sale,
0:26:40 > 0:26:44there's really only one substance we can rely on to combat sweat.
0:26:44 > 0:26:47And that's aluminium chlorohydrate.
0:26:47 > 0:26:50Think what you like about putting chemicals under your arm,
0:26:50 > 0:26:52but it really does work.
0:26:52 > 0:26:58And in my book, that really does earn it a place in our Wonderstuff hall of fame!
0:26:59 > 0:27:03When I started this journey into the world of wonderstuffs months ago,
0:27:03 > 0:27:05I had little idea what I was going to be in for.
0:27:07 > 0:27:10But it's one that's taken me all round the UK
0:27:10 > 0:27:12to meet some of our country's brightest brains
0:27:12 > 0:27:15who've turned up some genuine surprises!
0:27:15 > 0:27:18Wow! Science is really exciting!
0:27:18 > 0:27:20It's a good job I've got a strong heart!
0:27:20 > 0:27:21Wow!
0:27:21 > 0:27:25I'm never going to look at it in the same way again!
0:27:25 > 0:27:30One thing I love about having gone to the source to find substances we just can't live without
0:27:30 > 0:27:37is how it suddenly opened up this whole world of chemistry connections that surrounds us.
0:27:37 > 0:27:42Like the fact that there's the same active ingredient in moisturiser and explosives!
0:27:42 > 0:27:44I'm amazed!
0:27:44 > 0:27:48Or that the silica in toothpaste that makes it a stain remover
0:27:48 > 0:27:51also gives us hair dye and beer!
0:27:51 > 0:27:54- It's made from the sand we're standing on.- Really?
0:27:54 > 0:27:58Or that the chemical limonene extracted from the peel of citrus fruits
0:27:58 > 0:28:02is Nature's powerful gift to us when it comes to shifting grease.
0:28:02 > 0:28:06And it might one day turn up in anti-cancer medicine.
0:28:06 > 0:28:08Really impressive!
0:28:08 > 0:28:11We can all be enticed by a clever marketing slogan
0:28:11 > 0:28:13or eye-catching packaging.
0:28:13 > 0:28:19But sometimes, the real genius lies inside.
0:28:37 > 0:28:41Subtitles by Red Bee Media Ltd