This post is sponsored by La Roche-Posay.
“Do I really need to wear SPF every day?”
It’s the question I’m asked most often- and it’s the query I’m most passionate about.
SPF goes well beyond our perception of skincare. Adequate sun protection is a matter of health, and it deserves to be treated as such. While sun protection is an area under the “beauty” umbrella that I care deeply about, I often struggle to answer the more in depth questions I’m sent- reason being I’m an educated consumer, not an expert. These are questions that need to be answered though, so for this story, I’ve brought in the experts.
Dr Cara McDonald is a practising dermatologist who was generous enough with both her time and knowledge to sit down with Glow Journal and answer your skin health questions. While this story is sponsored by La Roche-Posay, all of Dr McDonald’s views are her own and she does not recommend any specific products throughout this interview.
This is something I’ve wanted to produce since the Glow Journal podcast was still in its infancy, and was waiting for the right producing partner to make sure the content was the best it can be. Those who have read glowjournal.com before or follow my personal Instagram account (@gemkwatts) will know that I am a long time user and lover of La Roche-Posay products, so this partnership felt like a natural and authentic fit. I have personally used La Roche-Posay’s Anthelios XL Ultra-Light Fluid SPF50+ Facial Sunscreen for several years now and have no qualms recommending it to Glow Journal readers and listeners.
In this excerpt from the Glow Journal Podcast, Dr Cara McDonald answers the SPF questions that you submitted.
GLOW JOURNAL: We know that the sun can do all sorts of things to the skin- perhaps we should start with tanning. What is a tan?
DR CARA MCDONALD: To understand exactly what a tan is, it helps to be able to visualise the skin.
It’s a little bit like having a brick wall of cells. Those cells that make up your brick wall are neat, perfectly laid bricks (if they’re undamaged cells), and along the bottom layer of your brick wall you have small, little pebble type cells. They just sit along the bottom layer and that’s what we call melanocytes. They are actually the cell that produces the pigment that results in a tan.
Underneath your brick wall is where your collagen, your elastin and your dermis sit. That’s also where your blood vessels and your nerves are, so I like to think of that as the foundation of the skin- below your brick wall.
When you get exposed to the sun, it’s actually the melanocytes that activate. They produce a pigment that then fills up those bricks with colour and then that acts to shade all that bottom layer of the skin- it will shade melanocytes, but it will also shade the basal layer of the brick wall, which is where our cells divide. They’re the ones that really need protecting because they’re the ones that, if they divide, could become cancerous.
A tan is pigmentation that’s produced by the melanocytes, but it fills upward into the other cells to shade the deeper layers of the skin.
There’s basically two types of tanning- one is that increased pigmentation that’s produced, and that’s mostly UVB, but the other is when UVA increases your tan by darkening the pigment that’s already there. It actually oxidises some of the pigment that was already produced and sits in those cells naturally, which is the pigment that gives us our skin colour. That can darken literally in hours, and that’s why after being in the sun you can look brown instantaneously- but that will also fade faster because those cells are higher up in the skin. The new pigment that’s produced will fill up those cells over a couple of days and that’s why you’ll get a tan as well that comes out more slowly.
If you’re getting a tan through your sunscreen, does that mean the SPF is not high enough?
Yes and no, and there’s a few reasons why. No sunscreen gives you 100% block of UV light. You are always going to get a little bit of UV through any sunscreen or any sun protection unless it’s a complete blackout clothing type protection. That’s why you will still see some tanning.
We also know that UVB is the one that causes what we see as a sunburn or red and painful skin, whereas UVA causes other skin damage but it does darken your tan as well. A lot of sunscreens have quite high UVB protection, so you won’t feel like you’ve got a sunburn, but you’re still getting enough UVA to tan and potentially enough UVA to cause premature ageing and other skin damage.
If you are seeing tanning, you are getting some sun damage. That’s that’s the bottom line.
We’re seeing a lot of tanning oils that claim to have SPF in them, but it feels counterintuitive to have a tanning oil with SPF in it…
Absolutely. It is counterintuitive. What you’re thinking is the bottom line- that if you are getting some tan then you are getting some damage. Obviously there’s a spectrum- it’s a degree of damage and what type of damage you’re getting as well. It comes back to using a low SPF- it will still reduce your sunburn, it will still reduce the DNA damage caused by UVB, but if it’s low [SPF] then you’re still getting enough rays through that you’re getting some tanning without the burning. But as I said, if you’re getting some tanning, you’re still getting some damage. So it’s still a choice.
If you want to use tanning oils [with SPF in them], you might not get as much damage as if you went without, but you’re still getting some damage if you’re still tanning.
Very top level- but what is sunburn?
Sunburn is irreversible DNA damage to the keratinocyte, which is that skin cell I talked about in the brick wall. When that DNA gets damaged, the body detects that as a bad thing because it’s going to become a cancerous cell down the track, or potentially immediately. It’s the body that then kills off those cells by a mechanism we call apoptosis, which is killing your own cells because they’re damaged or there is something wrong with them. The pain, the redness and the inflammation that we get is the body’s reaction to the DNA damage the sun has caused. It’s a radiation burn that damages the DNA, and your body will actually destroy those cells hence the blistering, peeling and so on that we see.
We know that sun exposure can lead to ageing of the skin. Can you talk me through this process?
There’s multiple different mechanisms by which the sun ages us. The way I like to think about it is, first of all, divided up into UVB and UVA. These are the main types of radiation from the sun that cause premature ageing. For a long time, we’ve known that UVB causes skin cancer and DNA damage to the cells. It penetrates to a depth where the bottom of that brick wall is- the bottom of your skin cells. That’s where the cells divide and if you cause DNA damage there, down the track those cells will be abnormal. They’ll be more likely to become a cancerous cell because you’ve got this baseline DNA damage that, down the track, each time they divide they can mutate further.
UVB causes DNA damage, but UVA penetrates deeper than UVB. Most UVA penetrates down into that dermis layer, which is underneath your cellular layer, but it does actually cause premature ageing and increases your risk of skin cancer as well.
UVA is probably more relevant in premature ageing because it causes more damage to the collagen. It makes collagen disappear faster by activating the enzymes that damage collagen. It decreases the immunity in the skin, which subsequently increases our risk of skin cancer, as well as causing premature ageing through inflammation. As well as that, it increases these reactive oxygen species, which is the oxidative damage in the skin, and that causes premature ageing and increases our risk of skin cancer.
It’s actually been relatively recently that we’ve realised that just because you’re not getting a sunburn reaction that’s killing off those cells, you are still getting a fair bit of damage from UVA and certainly a lot of premature ageing.
What is melanoma? And what role does the sun play in its development?
Melanoma is one type of skin cancer that we get. Broadly speaking, there’s two main types of skin cancer- we group them as melanoma and non-melanoma skin cancer. A lot of people don’t actually know anything about the non-melanoma skin cancers because they don’t tend to be as serious. They don’t generally spread to elsewhere in the body and, therefore, they’re not likely to kill you.
Melanoma can spread and is therefore more serious, but it’s actually much much less common than the non-melanoma skin cancers. I think it’s really important for people to understand that non-melanoma skin cancer is very common in those in their 70s at the moment- two out of three Australians will get one. That’s a very high incidence. Melanoma is much lower but more serious. Thinking back to that brick wall, the melanocytes sit along the bottom and if they become cancerous, that’s a melanoma, and if any of those other cells become cancerous, it’s a non-melanoma skin cancer.
The main differences are that one tends to be pigmented- it looks like a mole. It comes from a mole or freckle. The non-melanoma skin cancers tend to be more skin coloured or like a sore that doesn’t heal. They both need surgical treatment and both can be serious in their own right, in different people, so it’s very important to try and protect against both.
The bottom line is that the DNA damage that’s caused by the sun can lie there dormant in those cells. When I say “dormant,” the DNA damage remains, and every time those cells divide there’s a risk of a mutation. If the DNA is already damaged, that risk is much higher. You can have had sun damage when you were in your childhood, teens or twenties, and then in your fifties and sixties when your body isn’t as good at controlling that cell division and checking for mutations… it’s later on that you pay for the damage you had earlier. I see people all the time that say “But I don’t go in the sun,” and it’s about understanding that the damage earlier will haunt you later.
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We’ve touched on UVA and UVB and the difference between the two. Is a sunscreen that is “Broad Spectrum,” ie. UVA and UVB protection, enough? Or do we also need protection from things like visible light and infrared light?
Unfortunately, sunscreens are really complicated and labelling is very confusing for people. For that reason, people are still don’t protect well enough against UVA a lot of the time. Broad spectrum means that, now, there has to be a relative, adequate amount of cover for UVA compared to the UVB coverage which is labeled.
In an “SPF 50,” the SPF is specifically telling you how much UVB coverage we have. This is why our labelling has changed in recent years, because UVA was not accounted for adequately at all. It’s proportional. If the sunscreen is labeled “broad spectrum,” you know it has this proportional coverage of UVA, but you need it to be SPF 50 or above in the UVB for the UVA to actually be half-decent. In terms of UVB coverage. so SPF, there’s not a lot of difference between how much your prediction your protection you’ll get in SPF 30 versus 50 in terms of the amount that’s actually blocked. But, the corresponding UVA in those two products is very different. The bottom line is you want SPF labelling over 50 so that you know you’ve got adequate UVA, and it needs to be labeled as “broad spectrum”.
It needs to be SPF 50 and broad spectrum to know that you’ve got enough UVA coverage in there and that’s because there’s no standardised way to label UVA coverage. We’re relying on these terms that indicate it’s in there, rather than knowing exactly how much is there.
Until a few years ago, we only labeled in Australia to SPF 30+. The reason was because it was shown that consumers think that if it’s SPF100, they’re invincible. Even though we did have some sunscreens that are SPF100, it was thought that it was best to only label to 30+ because we wanted the message that you still need to be careful, you still need to reapply and you still need to not consider this as the be-all and end-all of all sun protection. We used to only label to 30, but then it was appreciated how important UVA is and it was realised that there’s a huge difference between 30 and SPF 50 in terms of what you UVA can be in there. Now, we can label to SPF50+. If it’s 50+, it means it’s actually at least 60, not 50. If you’ve got 50+ your UVA is pretty good, so long as it’s broad spectrum.
Glow Journal Loves: La Roche-Posay Anthelios XL Ultra Creme SPF50+. This hydrating formula offers broad spectrum SPF50+ UVA/UVB protection.
Another thing I’m asked a lot about is the difference between “physical sunscreens” and “synthetic” or “chemical sunscreens”. Can you explain the difference? What are the arguments for and against each?
To simplify it, “synthetic,” also known as “chemical” sunscreens, are specific chemicals that are designed to absorb UV light. UV light will be absorbed, and then it’s basically transmitted into a very low energy sort of heat. The way they work is that they get taken up by the outer surface of the skin, so they actually get taken into the sort of “dead” skin layer on top, and then they will absorb UV through the day. The reason that they have a longevity is because they basically get to a capacity where they can’t continue to absorb after a certain number of hours.
While chemical sunscreens absorb UV, physical sunscreens are really fine particles that actually reflect- much like how metals can reflect. They reflect UV back again, so they actually scatter it and reflect it away from the body.
What we know is that people worry about chemical sunscreens because they think that they will be absorbed into the body- but, in fact, very little is absorbed beyond the the outermost layer of the skin. The skin is very good at keeping stuff out. We have to put huge scientific development into finding ways to get active ingredients in skin care through the skin barrier. It [the skin barrier] is a very effective way of keeping stuff out of the body and, in most cases, these chemicals are not absorbed in any significant detectable amount into the body. They sit in that outer layer.
People worry about physical sunscreens because they have been linked to nanoparticles. Nanoparticles are just very, very small particles that have been essentially ground up. The reason we use nanoparticles is because otherwise you have the cricketer’s zinc on your face. Your physical sunscreens are zinc oxide or titanium dioxide, and both of them are visible on the skin and less used in a nanoparticle. Again, this has been heavily researched and the TGA has done a review of this and found that there’s no good evidence that nanoparticles in sunscreens enter the body. When we look at nanoparticles in the body, so in a lab situation for example, those particles in the body can cause DNA damage, which is where the concern has come from. But, again, they don’t seem to penetrate through the skin. Neither of these sunscreens should actually enter the body- they both act on the surface.
The one thing that most people don’t understand is that the combination together is what allows us to get a really high SPF. One on its own is never going to be as good. If you just use chemicals or just use physical, you tend to never be able to get as high an SPF as if you use them together. It’s a synergistic activity where the way they interact can give you a higher SPF.
You mentioned organic and how people see the word “organic,” and their mind goes elsewhere. There’s obviously difference between organic and natural, but is there such a thing as a truly “natural” SPF?
Mud? Clothing? In terms of commercially available sunscreens, no.
What is the definition of “natural?” This word, unfortunately, has no definition in skincare. It’s a marketing term. If you look at what it means for most people that use it, it’s “contains some ingredients derived from natural sources”. It’s so vague that you could put it on anything. When people say “I want something natural,” in most cases, they have no idea what they actually want. They don’t understand that natural doesn’t really mean anything.
One of the most natural things you can find is petrol. It comes straight out of the ground, but I wouldn’t put that on my face. It’s about looking for things that don’t cause problems.
We’ve talked about how natural is so vague, but I think the same goes for a word like chemical. People hear “chemical” and they panic, but really that encompasses just about everything.
It does encompass everything! Everything we eat, everything we use is a chemical. The terms have been, unfortunately, confused.
Speaking of sunscreens causing problems, I’ve been asked “What do I do if every sunscreen I’ve tried breaks me out?”
This is a common complaint and, in most cases, it’s actually an irritant reaction- not true acne. They look very similar, and it could be acne for some people, but an irritant reaction can look like little bumps on the skin or tiny little pimples, or more of a rash. There’s different kinds of reactions to sunscreens. There’s irritant, like I mentioned, there’s acne, from blocked pores or often from inflammation, and thirdly there’s true allergy. An allergy tends to give you an itchy rash, so it’s a bit different. It really needs to be taken back to the drawing board to work out what sort of reaction they’re getting.
The most common [reaction] is irritant, so we look for sunscreens that have the least number of irritants as possible. Fragrances are irritating, so look for fragrance free, look for low allergy or hypoallergenic formulas, and non-comedogenic formulas, meaning they don’t cause acne. Sunscreens that are specifically formulated for sensitive skin tend to stop people from breaking out.
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Let’s talk about applying our SPF. Do we need to leave time in between applying our sunscreen and exposing our skin to the sun?
Ideally you you’re looking for a few minutes. Most sunscreens recommend 10 or 20 minutes. The reason for this is because they are actually absorbed into that top layer of the skin. Anything that you put on the skin takes a little while to absorb properly, and the more time you give it to absorb, the better it’s going to function. If you literally have to walk out the door, you’re still better off putting your sunscreen on and it’s going to give you some protection immediately, but the full protection might be once it’s fully absorbed and doing its job.
The problem with not giving it that time is that if you put makeup on top of it, you rub your skin or jump in water, you might rub some of it off where it hasn’t actually been absorbed yet. If you give it that time, it doesn’t just rub off because it’s actually in the skin cells.
Is there a hard and fast rule as to how much sunscreen we need to apply?
There are guidelines for this, and that is because when testing for SPF is done, it’s done in a laboratory kind of situation. It’s done on real skin, but the way it’s done is that the sunscreen is applied to the skin with to say “If this skin will burn or start to go red in 10 minutes without any sunscreen on, how long does it take once you’ve applied the sunscreen?” SPF is sun protection factor, and if it takes 50 times as long to go red with the sunscreen as compared to without it, then that will be an SPF 50.
That’s a very controlled environment. It’s an even, controlled amount of UV that’s being applied. There’s no sweating. There’s no swimming. There’s no rubbing the skin, and a very specific quantity [of sunscreen] has been applied, so if you don’t apply that same quantity and you’re not in the same environment, the SPF will be a bit more variable than what’s been measured in the in the lab situation.
In terms of applying it, generally the more the better- but it needs to be cosmetically acceptable as well, so you’ve got to find your balance there. For the face and neck, it’s approximately 1/2 a teaspoon that gives you the amount that is used for that SPF.
I always explain to people that if you’re painting a wall in your house and you put one coat on, it never looks even. It’s always a bit patchy. Whereas if you put a second coat on, all of a sudden it looks pretty even. That double application will have a great benefit if you are going to be outdoors all day or you are really going to be in intense, middle-of-the-day sun.
SPF in foundation- how much would we need to be putting on our face to be effectively protected from the sun?
The bottom line is you couldn’t put enough on. It’s not going to be high enough. You’ll find that with most foundations. There are some with highest SPF, but most are fairly low and therefore they’re not going to have very good UVA coverage either.
Most of us are worried about premature ageing as well as skin cancer, so we want to make sure we’ve got that covered. I suppose some is better than none in all situations, but if you want the best protection you can get you, are not going to get it just from foundation. Use sunscreen.
In what order should we be applying sunscreen in the grand scheme of our skincare routine? Does that order differ for things like zincs compared to synthetic or chemical sunscreens?
Think back to the skin- this makes it really easy. If you think about the layers of the skin, the first thing you’ve got to put on is whatever you want to go deepest. Active ingredients, you want them to go into the deep layer of the skin, so put them on first. Moisturiser, you want to help improve your barrier which is the top layer of the skin, so put it on next. Sun protection, you want it on the top layer of the skin, so put it on last. If you’re going to apply makeup, that’s a “camouflage” type application, so goes over the top of that. That’s always the order. It doesn’t really matter whether its a chemical or physical blocker- it should always go after moisturiser, before makeup.
What kind of sunscreen should we look for if we want to avoid a white cast in flash photography?
The white cast is usually due to those reflective sunscreens- the physical blockers which will reflect light. With a flash, those will reflect the light back at you. What you need to use is a chemical sunscreen without physical blocker.
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Hypothetically if we only apply our SPF first thing in the morning, how long will it last?
Well, if you go back to that sun protection factor and you’ve got 50+, which means that you’ve got SPF 60 coverage or higher, you’re looking at eight to 10 hours in laboratory conditions- which is not real life. However, it’s certainly fairly long lasting protection and if you’re not sweating, swimming or rubbing it off, you do get reasonably good coverage all day.
The reality is that most women are not going to take off their makeup, put sunscreen on and reapply their makeup during the day. It’s just not reality. It’s not realistic- so use the best sunscreen you can. Often people do ask me “Which sunscreen? What brands?” and so on, but it’s the sunscreen that has the highest SPF that sits on your skin well for the day, that’s not too expensive (because you don’t want expensive sunscreen that you just use a few drops of)- sunscreen is the one thing that you do not want to skimp on. I would far prefer people use an affordable sunscreen, so long as it’s got the right SPF, that they can use enough of to get that great layer up front. I certainly don’t reapply during the day unless I’m outdoors during the day- then of course I will.
Worst case scenario, you’re going to the races or something, you know you’re never going to reapply your sunscreen all day, so use hats and make sure you’re in the shade during the middle of the day. Use those other types of sun protection that we know work to complement the good SPF you’ve put on at the beginning of the day.
If we do work outdoors and aren’t wearing makeup, how often should we reapply?
The recommendation would be every two hours. For tradies and outdoor workers, I highly recommend two hours, but if they say “I’m just never going to do that, I’m filthy dirty, I’m sweaty, I can’t put it on,” there’s a couple of tricks. One is to just get an aerosol type spray- just spray it over the top of everything else that’s on your skin. Then, when they have a lunch break, I ask them to get baby wipes or a wet towel to give their skin a clean and reapply properly in the middle of the day.
Glow Journal Loves: La Roche-Posay Anthelios XL Ultra Light Body Spray Sunscreen SPF 50+. Suitable for both the face and body, this spray-on formula is ideal for reapplication throughout the day.
To wrap up- what is the easiest and most effective way to convince those around us that we need to wear SPF everyday?
There’s two things. One, Australia has the highest rate of skin cancer in the world. We know the sun causes skin cancer. We don’t have any good evidence that sunscreens cause any worse problem than that. So, if you want to choose, I would choose to prevent skin cancer- which we know can be deadly.
Secondly, Australian women photo-age well ahead of their years compared to other countries. One study has shown that we can be aged about 20 years older than most European or overseas women at the same age, and that’s due to sun damage.
We know it causes skin cancer, we know it causes premature ageing. It comes down to a choice. Which one do you want- sun protection, or those two things? It’s about making it a routine.
I do like to explain that UVA is there 365 days of the year. It’s fairly consistent. Even if you’re not burning, even if you’re not outdoors for more than a couple of minutes walking to your car, hanging out the washing or going to the supermarket, you can still be exposed to enough UVA to age prematurely and potentially get skin cancer down the track. Don’t worry about the weather. Don’t worry about what time of the year it is. Don’t worry. If you can’t reapply during the day just put it on once a day when you brush your teeth. You will be a lot better off in 10, 20 years time than you would be otherwise.
