In partnership with La Roche-Posay.
In this excerpt from the Glow Journal Podcast, Dr Cara McDonald answers the SPF questions that you submitted. To listen to the full interview, subscribe to the Glow Journal Podcast now on iTunes or Spotify
GLOW JOURNAL: Quite a few questions popped up that we did cover on our last SPF episode, but I do think there are a few points that it’s definitely worth covering again. Before we actually talk sunscreen specifically, though, I would love to start on the sun itself and why we do actually need to be wearing SPF every day. So to start, what are UVA and UVB rays? And what are they actually doing to our skin?
DR CARA MCDONALD: UV light is the non-visible part of the spectrum from the sun. There’s actually UVA, UVB and UVC. UVC largely doesn’t hit the earth’s surface, so we don’t worry about that, but this is probably the most damaging to DNA. It’s used in UV cleaning, which we’ve heard a lot about lately, but it’s not great to apply anywhere near the skin. So stay away from any any UV cleaning rays.
UVA is the longer wavelength, and it’s from 315 nanometers up to 400. Being a bit longer, it penetrates a little bit deeper into the skin. It mostly goes past the epidermis down into the dermis, and it really affects our immune function in the skin and our collagen production, but it also causes some DNA damage of the cells.
UVB is slightly shorter, and it penetrates less deep and hits more the epidermis, which is the cellular layer of the skin. That’s why it causes sunburn. It is more responsible for the DNA damage that causes skin cancer directly, but actually it’s the combination of the two [UVA and UVB] that’s most problematic.
So do we really need protection from the sun year round? Is UV always present?
Yes, absolutely. It’s present all year round. It is higher in the summer months, particularly UVB. UVA is more constant. It’s present all through winter, and it penetrates through clouds and glass. It’s not as obvious to us. We don’t feel it like heat and burning on the skin, which we do UVB. So UV is fairly constant all year round, even though the cumulative UV is definitely higher in summer.
We’re a bit like politicians, I suppose. Sometimes there’s no right answer about whether you need UV protection. You’ve got to weigh up the pros and cons. So if you’re interested in anti ageing, you need UV protection every single day of the year because we know that UVA is the most ageing and it is present throughout the year. If you are worried more about your vitamin D and you’re not getting excessive exposure and you’re not worried about anti-ageing effects, then there’s an argument that there are certain months of the year when you can go without sunscreen.
I would love to hear more about what the UV index actually is. How do we determine what the UV is on any given day?
The UV index was actually developed by the World Health Organisation and it’s really a vehicle for public awareness. They’ve basically arbitrarily made up a sliding scale of UV, which takes into account the weather, the position on the earth, how close you are to the edge of the equator, it even takes into account pollution and reflection as well. So it takes into account all of the things that actually determine how much UV you will be exposed to as a person at any given time of the day in any given area in the world. It’s a global solar UV index and, really, it just simplifies it for the public so that we know how much we’re going to be exposed to, rather than talking in joules per centimetre square. They have a sliding scale of 0 to 11.
I’ve had a listener ask “Is there a need to wear sunscreen when the UV is below 3?”
It really depends what you’re worried about. We don’t see much sunburn and we don’t see much increased risk of skin cancer if the UV index is below 3. But remember that’s just 1 and 2. However, we do still see some effects of UV light, particularly on our signs of ageing. From my point of view, I don’t want to have to check the time of the day and where I am and whether or not the UV index has gone above 3, because most of the time when I’m outdoors, it’s above 3. So, personally, I would just suggest that we wear it all the time, particularly in those areas that are frequently exposed, like the face.
I actually deleted the UV index app off my phone, because I feel that if you’re checking it every morning and then basing your decision off that, there’s so much room for error. There’s just no point chancing it.
There’s just no need. It’s so rarely below 3, we should just wear it [SPF] every day.
So we’ve got UVA and we’ve got UVB- how do we make sure that we’re choosing a sunscreen that is protecting us from both?
Unfortunately, sunscreen labelling is complicated, but there are a couple of simple rules you can follow. We are frequently asked this question because, unfortunately, there’s different regulations about labelling and different rules in different countries.
Primary sunscreens are labelled differently to secondary sunscreens, which are more like cosmetics or cosmetic sunscreens. So we need to, preferably, if we’re looking for a good sunscreen, look for a TGA approved sunscreen in Australia.
Then, we’re looking at the two main labelling categories in Australia, which are SPF and broad spectrum. SPF gives you the protection against UVB rays, and that’s the Sun Protection Factor and it’s calculated as a time factor- so how much longer are you protected from UVB rays before you will burn, by that particular product. Broad spectrum is really the only reliable category in Australia, which tells us whether or not it’s got adequate UVA coverage as well. And of course, we want both.
It’s complicated, because there’s no a huge degree of difference between SPF 30 and SPF 50 in the amount of UVB coverage. It’s an exponential sort of scale. So in the low SPF, say under 30, it’s a big increase for every increase in SPF in the amount of protection you get, but as you go above 30 it flattens out, whereas the UVA coverage is proportional to the UVB in most sunscreens and it’s more of a linear scale. So once we get to 30 SPF, the UVA coverage is still going up quite dramatically, all the way to 50 SPF.
If I’m looking for a sunscreen, I’m always looking for SPF 50 and broad spectrum. This means that you’re pretty much guaranteed to be covering UVA and UVB to the best of its ability.
My next question was going to be “What’s the real difference between SPF 30 and 50+,” because I had so many people saying “Oh, but I’ve heard 30+ is not really any different, so I’m just going to wear that.” But there you go. You’ve covered it.
Yeah, so they’re exactly right in that the UVB coverage is not a lot better at 30 or 50. But when you then have to take into account the anti ageing side from the UVA, it’s also responsible for skin cancer. Then the UVA is significantly different around SPF 30 and SPF 50. So to get the best of both, we really wanted to look for that SPF 50+. a50+ actually means it’s SPF 60 or higher, just to make it even more confusing.
I’ve had a few people ask “Does wearing SPF 50+ each day block or halt our vitamin D absorption?”
We get asked this a lot, and the bottom line is that we actually produce the vitamin D in our skin. With the UV, there’s a photochemical reaction in the skin to produce vitamin D. Vitamin D is really important for bone density and our immune system, and probably even cancer protection as well. So we definitely want to pay attention to vitamin D.
It’s interesting because it’s UVB that does trigger vitamin D production, and if you’re protecting the skin with sunscreen against vitamin D, then you would expect that there has to be some decrease in the vitamin D production.
Studies don’t show a significant difference between the amount of vitamin D in people who wear sunscreen strictly and those who don’t, and perhaps that is due to all the confounding factors where we see differences in the amount of time people are outdoors, so those that wear sunscreen a lot might be outdoors more and get more incidental sun anyway.
If people are particularly concerned about vitamin D, first of all, I suggest supplementation, which is easy. The other thing we can do is always make sure we’re protecting the areas that are frequently exposed to the sun and the areas where you’re concerned about pigmentation, skin cancer, or signs of ageing- so the face. The vitamin D is produced on an area basis, so as long as you leave a little bit of unexposed skin that can get the sun to produce vitamin D, you’re better off doing that elsewhere on the body instead of the face.
It does, most likely, reduce it, although it’s difficult to know exactly how much.
I’ve had a lot of people write in to say they’re confused by the amount of choice, as far as sunscreen goes. One listener has asked “What is the most important ingredient to look for in a sunscreen?”
Sunscreens are quite complex and there are many different chemicals or ingredients that actually go in to make a sunscreen, so it’s impossible to give a particular ingredient. The one thing that you can look for is that SPF and broad spectrum labelling and, as I said, TGA approved, just to ensure that it is a primary sunscreen because they are very different to cosmetic sunscreens, which are not actually approved and may not have the same protection as a primary sunscreen does. So I would say just look for SPF.
I had even more people ask “What ingredients should we avoid in sunscreen?” But I imagine that answer is going to be quite similar to what we’ve just touched on.
Yes, I am just happy for people to use any sunscreen as long as it’s high protection. For people with any skin condition or who have had problems with sunscreen before, they’re the ones that really do need to look for ingredients to avoid.
The number one would be fragrances. A lot of people get irritation from sunscreen and, more often than not, it’s from the fragrances in the sunscreen. It’s also sometimes from the preservatives that are in them, and then less commonly actually the sunscreen ingredients themselves. So if you do have trouble with sunscreens, look for fragrance free, low preservatives, suitable for sensitive skin, hypoallergenic… those sorts of labels are what you should be looking for if you’ve had problems. But if you like the sunscreen and it’s not causing you any problems, and it is SPF broad spectrum 50+, then it doesn’t really matter.
This was the question I got asked the most, I get asked this every day even when I don’t do a specific SPF question callout- at what stage of our skin care routine should we be applying our SPF?
A fantastic question this one, and I get asked this a lot as well so I’m not surprised you do too.
I think the way people remember it is if they think in layers. So anything active, active ingredients are generally targeting the deeper layers of the skin where they’ll be metabolically active.
So active ingredients and generally serums go on first, and they will be absorbed the fastest and go deepest. The next layer is going to be our barrier support and hydration. So that generally is moisturisers things like hyaluronic acid, which will hold moisture into the skin. And on the top layer is sun protection.
Sun protection is designed to stay in the top layers of the skin, in the stratum corneum, which are the non-active or non dividing cells of the skin. They are meant to remain in that layer of the skin. We don’t want them to be absorbed in deep in the skin. So you really want to think about it as going on top, like our umbrella. It should be the top layer of skin care, other than makeup, which can go on top of that obviously for cosmetic reasons.
What is the difference between physical/mineral sunscreen, and chemical/synthetic sunscreen?
This is another really good question because it is so confusing for people. I’m going to try and really simplify this.
Physical sunscreen is also called inorganic sunscreen. That is a titanium dioxide or zinc oxide. These physical sunscreens, previously people talked about them reflecting the light off the skin, and they do do that which chemical sunscreens don’t, but they also transfer that energy into heat, as do chemical sunscreens.
The confusion comes from the name- “inorganic” and “organic”. Inorganic being those physical blockers. In chemistry, organic chemicals are those that contain a carbon and hydrogen bond, and really anything living is either organic chemicals or derived from. Inorganic chemistry is when you’re thinking of minerals and more nonliving things, like metals and minerals. The problem is that we now use organic also to mean organic farming or natural products that have been produced with no chemicals. So there’s a lot of confusion because an organic sunscreen is a chemical sunscreen, and people get that confused with organic foods and other organic skincare, which has meant to be chemical free.
So hopefully that makes sense- organic sunscreens come from chemistry and they are the chemical sunscreens. They are a variety of chemicals which actually absorb UV light and turn it into heat, and then physical sunscreens are the more physical blockers. I like to think of them as coming from minerals. They do reflect a bit, but also absorb the UV light to protect the skin.
I know there’s no real answer for this next one, but I thought I’d throw it in there anyway because so many people sent it in. A lot of listeners have asked out of those two categories of sunscreen, which is better?
Well, there is an answer to this actually!
Chemical sunscreens are better. And that is because it’s almost impossible to get SPF 50+ and broad spectrum just from physical blockers. Physical blockers tend to give that white cast look if you have a high enough protection to get up to above 30+.
From my point of view, unless you have a real problem with chemical sunscreens (which is really rare- as I mentioned most people have problems with the additive ingredients in sunscreens, not the actual chemical sunscreen itself), then you’re better off with a chemical sunscreen. If you’re worried about pigmentation, ageing and skin cancer, a lot of people hear “chemical” and think “Oh my goodness I don’t want to put chemicals on my skin, what if it gets absorbed in?” Well, we know that the newest sunscreens are quite large molecules and they really are designed not to be absorbed. We want them, as I said, in that sort of non-viable layer of the skin. And there’s a lot of evidence that the chemicals do not penetrate through the epidermis and they don’t into the bloodstream at all. So these are chemicals that really do what they’re meant to do and stay on the surface protecting us. There’s also been concerns about physical blockers because they’re the ones that actually become nanoparticles, because we need them to be ground up very, very small in order for them to not be visible on the skin. And, again, the evidence is that they’re not penetrating through the skin of being absorbed into the body. So they both should be very, very safe. But you’re likely to get much higher SPF from chemical sunscreens.
If you’ve got very sensitive skin or known allergies to chemical sunscreen, you may tolerate a physical blocker better and they’re really the only people I would try to get to use a physical blocker.
Whichever one we choose, say organic or inorganic, does that change the order of application at all? Or is it still going on after our skin care?
They should definitely both go on after all other skincare and before makeup. They should both be on that top layer of the skin, and that’s where they will do their job- to absorb UV light and stop it penetrating into our skin where the alive cells are prone to DNA damage.
Do the skincare products that we’re applying our sunscreen over the top of, sayif it’s a facial oil, or a moisturiser, do those products have any impact on the efficacy of the SPF that we’re putting over the top?
It’s a good question because there’s no a lot of evidence around this actually. Most of these SPF tests are done in lab environments where we don’t take into account all these other factors.
What we think is as long as the other products have been absorbed (and depending on what it is that will depend on how long that really needs- say if it’s a really oily substance, you want to make sure that you massage it in well, or give it a few minutes to absorb before you apply a sunscreen)… basically, if it’s still on the surface of the skin and you then sort of mix it with your sunscreen, you are effectively diluting the sunscreen. If it is an oil based product, it’s possible that it decreases the absorption just into the stratum corneum of the sunscreen base, the cream itself, so that it doesn’t stay on the skin as well. It’s more likely to rub off or sweat off than if you’ve got a nice clean surface to apply it to.
I received so many questions asking about the best way to apply sunscreen over makeup. This is something that we did cover in our last episode, but to recap, how often do we actually need to reapply sunscreen if we are working indoors?
My advice here is that, so long as you use a really good quality sunscreen at least once a day in the morning under your makeup, we know that the good sunscreens are photostable and they are long lasting, so you do get good protection all day from an SPF 50+ sunscreen if it was applied in an adequate quantity and you’re not then sweating, rubbing it off or out in the sun too much.
The sun itself can break down sunscreens a little bit. So if you’re indoors and you’ve got a face full of makeup and you’re working all day, I don’t think you need to reapply your sunscreen during the day. If you were going outside at lunchtime for an hour for a run in hot sun, then absolutely you would want to reapply. But, in that case, you’re probably going to be redoing your makeup.
If, on the other hand, you are going to be outdoors in the sun all day, then we’re looking at a very different scenario because we know that the protection is only as good as it’s stated if it’s there in the quantity that it was needed and also if it hasn’t been broken down by the sun. And so if you are going to be outdoors all day, then we do need to look at reapplying it.
The times where it’s difficult is if we’re going to an event that’s outside and we do have makeup on, we don’t want to be reapplying it all day, but we are in the sun and there are a couple of things or techniques we can use. First of all, try to minimise the sun that is directly on your skin, because that will do two things. It reduces your exposure, but it also reduces the breakdown of the sunscreen that you have put on in the morning. So using hats, using shade and avoiding direct sun as much as possible, if you are going to be in the sun.
Then there are a few techniques that can work, like just putting a small amount of a very, very light sunscreen and just re-dabbing it over the top of your makeup is better than nothing. And you can usually do that without smudging your makeup too much. You might then reapply a powder or something to set it again. Another technique is to use a spray-on sunscreen. Some alcohol type based sprays will actually sort of evaporate off and leave your makeup fairly in tact, but probably add a bit more sun protection as well. But, again, we don’t have any good evidence to say how effective they are when applied a little bit over the top of makeup, but most likely it’s better than nothing.
I’m glad you’ve mentioned sunscreen sprays because a lot of people have asked if the consistency of the sunscreen itself impacts its efficacy- for example, a fluid or a cream compared to something like a spray or the powders that we’re seeing a bit more of now.
It doesn’t effect the SPF if it’s applied in the quantity that is recommended and was used when they did the SPF measurements. The problem is, with a spray or powder, it’s very hard to know how much you’ve put on. With most sprays, you’ll actually see that they recommend spraying it into your hand and then applying it onto your skin. I think a lot of people with sprays tend to end up with patchy sunscreen because they haven’t really gauged how much they’ve applied.
I think it’s easier to be sure you’ve got a good cover if you’re using a cream or a lotion but, as I always say, something is better than nothing. Just be mindful that, if it’s a spray, you need to be extra diligent to double spray, double coat, reapply more often to make sure you haven’t left any gaps.
On a similar note, and something else that we have covered but is definitely worth recapping- can you explain why a foundation or even a basic moisturiser with SPF in it is not a substitute for your sunscreen?
Unfortunately this is where a lot of people fall down. They see SPF on their products and they assume that they’ve got good sun protection. This is where we really need to improve the labelling in this country, because a cosmetic product and anything that is not a primary sunscreen (so anything that’s not a sunscreen- any foundation, any makeup product), doesn’t have to be TGA tested and approved to have sunscreen or SPF labelled on their product. Whereas something that’s a primary sunscreen, so something that really is just a sunscreen or is marketed as a sunscreen, needs to have proof and be tested.
So the bottom line is that, first of all, the makeup products are unreliable. So what they say is the SPF or sun protection is not necessarily accurate. And the second thing is that we just don’t apply them in the volumes we need to get an adequate protection.
We need to get an adequate protection. If you put the same amount of foundation on as your sunscreen, then it will generally look pretty terrible. Then your SPF is never going to be as high anyway, because it’s unlikely to be what is stated. So you’re always better off putting both on (sunscreen and makeup) if you can, and making sure that the sunscreen you use is a high protection and TGA approved one.
I think you did actually cover this earlier, but a listener has asked “Can I mix my sunscreen with my moisturiser and will it stay effective?
So, again, it’s just a problem with not knowing then what your SPF coverage is. If you are going to mix your SPF with anything, you are going to dilute it. So first of all, it’s not going to be as effective. And secondly, you just don’t know whether it affects the absorption, where it will sit and how it will change the SPF coverage that you’re getting. So my recommendation is put the moisturiser on first, or find an SPF product that’s hydrating in itself. And there are plenty of really good ones out there. Many people will find that if they get the right sunscreen, it covers both bases, particularly on the face, and then you’ll only need SPF, and you’ll actually use a little bit more of it. If you haven’t used moisturiser already, you tend to use a bit more sunscreen and that will give you a much better protection and be better for you all day long.
A heavier subject, but something that we absolutely need to cover, is skin cancer. We know that, at its worst, the sun can cause cancer. Something that we have touched on previously, but is essential to reiterate, what is a melanoma and what role does the sun play in its development?
We all need to remember about skin cancer in Australia, because we are world leaders, unfortunately. Melanoma is one type of skin cancer. It’s actually the less common type, but the more deadly type. That’s why we worry about it so much.
Melanoma is basically a cancer of the melanocyte. The melanocyte is the cell that sits in the top layer of our skin and gives us a tan. The job of the melanocyte is to actually rapidly produce some pigmentation called melanin when it’s exposed to UV light, and that melanin then gets taken up by all the other skin cells to act as a shade. So it’s like a shade cloth over the dividing layer of cells, which is really important to prevent further UV damage. The melanocyte is also responsible for our skin colour, so someone who’s very fair will have fewer melanocytes than someone with a darker skin tone or black skin.
So the melanocytes do a great job at protecting the skin, but they are also prone to being damaged by the sun themselves. We know that painful sunburns as a child is one of the greatest risk factors for melanoma later in life. The DNA damage can be done many, many years before that cell actually becomes cancerous. I frequently see people who say “But I never go out in the sun anymore,” and they can’t understand how they got their skin cancer later in life. But then damage was actually done as a child or as a teen, and then you have this low grade DNA damage. The body basically keeps it in check and makes sure that the cell doesn’t progress into a cancerous one with another mutation, but as we age or over time, a cell can escape the system. As soon as it starts dividing and escapes the checking mechanisms, it becomes a cancer or a skin cancer. Melanoma has a risk of spreading through the body. And that’s why we worry about it so much.
You mentioned that we are the world leaders in skin cancer, which is not the greatest of titles, but just so that people are aware that no one is immune to this, how common is skin cancer in Australia?
We don’t know exactly how common all skin cancers are because not every skin cancer is registered. We broadly divide them up into melanomas and non-melanoma skin cancer. Melanomas are counted, and over the last 30 years or so, our rate of melanoma has actually doubled. It’s approximately 50 cases per hundred thousand a year, and I think roughly 2000 people a year die from melanoma in Australia.
On the other hand, non-melanoma skin cancer (which comes from any other skin cell that we have) it accounts for many, many, many more times the rate of melanoma, probably up to a hundred times as many, but there’s only a fraction of them that are actually fatal or that spread. So even though they are far more common, we know they are less likely to cause severe harm.
The statistics seem to indicate that the rates of skin cancer are still good going up as our population ages. But the rates in young people are definitely decreasing, which is great news. There are fewer melanomas in the under thirties now than there were 20 years ago, but more in the elderly population who had that damage when they were younger.
As far as keeping an eye on our own skin, what should we be looking out for?
That’s a really good question. And unfortunately, I think even though there have been lots of public campaigns about self skin checking and getting your skin checked, people still don’t know what to look for and what to see their doctor about. It’s hard to clearly define it and cover all variabilities, unfortunately.
We use an ABCDE screening tool, which helps some people. We’re looking at Asymmetry in the mole, so an uneven looking mole, we’re looking at the Border, so is the border changing or irregular, the Colour, most melanomas have more than one colour in them (and again, that’s difficult sometimes to understand, but they often look a bit black, a little bit brown, a little bit pink), and then you’ve got Diameter, so most melanomas are greater than six millimetres, and E is for Evolution, which is probably the most important because evolution covers anything that’s changing and, by definition, Cancer is something that is growing. There is no such thing as a cancer that’s not changing- that’s what cancers are. I’m always explaining to people that if something is changing, then it should be checked. Always. Because most benign skin lesions, you might wake up one day and you’ve got a new freckle or a new sunspot, but then it just stays the same and they tend to look like your other spots, the benign ones. Whereas melanomas tend to look different, but they’re always changing or growing.
And I think that’s the main message for me, is to get something checked if you don’t feel right about it or if it’s definitely changed.
How often should we be visiting a professional for a skin cancer check?
That’s another question that many people don’t know the answer to, and we really need to get that message out there. The best solution is to at least get one check done. And once you’ve had one check done, then if you’ve seen a professional, they will be able to guide you as to how often you should be getting your skin checked. So I’d like everyone in their twenties at least to get a skin check. And then get professional guidance about their risk factors, the main risk factors, because we look at family history, having lots and lots of moles, sunburns as a child and longterm sun exposure as well. So they all contribute to your individual risk, but having a professional check your skin, educate you about what to look for, what to worry about, what not to worry about, and then also give advice about how often they think you should get checked. It’s probably the best idea for each individual.
It really varies. Some people should be being checked once a year or twice a year and others, if they’re very low risk and young, you would say you can watch your own skin so long as you’re aware of these things you should come back with, then that’s fine if you’ve got almost no spots and you’ve had very little damage. Most people are safe not to have a regular skin check with a dermatologist.
For anyone who perhaps hasn’t had a skin check before and might be a little bit nervous to go, what can they expect? What’s involved?
Don’t be scared- most of us are pretty friendly!
What we’ll generally do is really check your body top to toe. We’ll check all the bits of skin that you might not be able to see and give you advice about what to look for, where you might need to look and which spots you might need to keep an eye on. When I do a skin check, I’ll be looking right through the hair, looking at the scalp, looking behind the ears, looking between the toes, looking in the creases. Most of the time, what we do is strip down to underwear, so bra and undies will stay on, and then we work around those areas to make sure we’ve checked all areas that have had some exposure and double check whether there are any other spots on your body that might be still covered up that you want to have checked. And then it’s really about that education and making sure you know what to look for and what to keep an eye on.
An all encompassing note to wrap up on- why do we need to wear broad spectrum sunscreen every single day, and how do we convince those who think, for whatever reason, that they don’t have to?
An excellent point to end on! We both agree that sunscreen every day is preferable.
Sometimes we need to look at it from the individual’s point of view thoug- if they have risk factors for skin cancer, they need to understand that even a little bit of sun on any day, even if it’s cloudy, even if they’re not getting sunburned, even if they can’t even feel the sun, even if they think they’re only outdoors for five minutes getting in and out of their car, if they’ve already got damage on their skin or they have personal risk for skin cancer, then every little bit adds up. So if you can put brakes on that and protect from any point moving forward, we know that that reduces your risk of skin cancer in the future.
If you are worried about photo ageing, reduced collagen, wrinkles, pigmentation, any of the problems we see from the sun, then it’s a no brainer. We have to protect every single day. We know that ageing process is extremely fast, it’s accelerated in Australia due to even incidental sun exposure. And we only have to generally look at our abdomens to see the difference between the areas of our skin that has had [sun] exposure throughout our life and an area that’s been protected most of the time. There aren’t many women past about 25 who can’t see a difference in the skin on their face, just due to that day in day out little bit of sun. So the sooner you start, the better off you’ll be down the track. It’s much better to prevent and much easier to prevent than it is to treat the premature ageing that we see from the sun down the track.
