The 3 biggest myths about anti-aging skincare with Prof. John McGrath

From collagen powders to $100 creams, the skincare industry thrives on promises. However, many of the products we rely on for younger, healthier skin are built on shaky evidence.

In this episode, world-renowned dermatologist Professor John McGrath breaks down what’s real and what’s not.

John McGrath is a Professor of Molecular Dermatology at King’s College London and editor of the British Journal of Dermatology. His research has transformed how we understand genetic skin disorders and vitamin D’s role in skin health.

This conversation is packed with surprising insights - and one daily step that really does support healthier skin as you age.

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Transcript

Jonathan Wolf: John, thank you for joining me today. 

Prof. John McGrath: My pleasure, Jonathan. 

Jonathan Wolf: So we have a tradition here at ZOE where we always start with a quick-fire round of questions from our listeners. We have some very strict rules, which are designed to be really hard for scientists and doctors, because you can only say yes or no. If you have to, you can give us one sentence. 

Are you willing to give it a go? 

Prof. John McGrath: Yes. 

Jonathan Wolf: Is it a problem that our skin ages? 

Prof. John McGrath: No.

Jonathan Wolf: Do anti-aging skin creams have to prove they work before they hit our shelves? 

Prof. John McGrath: They don't. 

Jonathan Wolf: Could certain genes create a natural sunscreen? 

Prof. John McGrath: Yes.

Jonathan Wolf: Is collagen powder a silver bullet for better skin?

Prof. John McGrath: Definitely not.

Jonathan Wolf: Is there a way to reverse a sunburn in 24 hours? 

Prof. John McGrath: Absolutely.

Jonathan Wolf: Ooh, that one I wasn't expecting. You have a whole sentence now. What's the biggest myth when it comes to aging skin? 

Prof. John McGrath: The biggest myth is probably that people think there's a magic elixir they can just go out and purchase that will turn back time, and that just doesn't exist.

Jonathan Wolf: And we're going to get into what some of those are later in the episode.

My wife is a dermatologist, so I live in this bubble where the only really interesting thing is skin. And so, because I often see what's on Justine's feed, I feel I'm constantly being sold a 10-step skincare regime or some powder supplement with a fancy scientific name that promises to stop my skin from aging.

And I've now hit a certain age, so even though I'm starting to get a little bit more interested, but I do feel like it's impossible to understand what actually works. 

You said this really interesting thing about how skin aging isn't necessarily bad. So, could we start there? What's actually happening on the surface of my skin every day?

 Prof. John McGrath: Well, this amazing organ that you have, the skin, as an adult, you've got 1.8 square meters of amazing carpet, which we recognize as this barrier that keeps the outside out and the inside in, and also has its own appearances too. 

It's a very dynamic structure. The outer layer of your skin is replacing itself every four weeks in reaction to the external environment. You really have to build up this barrier to protect yourself.

And it's rather amazing what skin can do in terms of its function. It's there not only to look nice, but it also protects you. It protects you against inflammation, against infection. It makes hormones, it makes vitamins. It has its own immune system.

It's a fabulous organ, and so it's worth thinking about and worth preserving. And of course, over the course of our lifetime, it does change a little bit, and sometimes it doesn't always work as well as it did in earlier life. 

But that's part of a natural process for this amazing organ, our skin.

Jonathan Wolf:  It's so funny, I'm listening to this and you sound just like my wife, which is, I could see, you could talk about the skin forever. Am I right that you think the skin is probably the most important organ in our body?

Prof. John McGrath: Is there anything more important than skin? Cardiologists might disagree. Neurologists might disagree, but I think dermatologists have got it right. 

Jonathan Wolf: I love it. Now, one thing you didn't mention that I hear a lot more talk about than before is the microbiome of the skin. So, is it true, does the skin have its own microbiome?

Prof. John McGrath: Absolutely. I mean, your skin is made of 35 billion cells. But on top of your skin, on the surface, and down the hair follicles are 70 billion bugs. 

So the microbiome really has twice the number of cells that there are in human skin. And this microbiome, this ecosystem that we have on our skin, is very important in helping the function of the skin and also in deciding our susceptibility or resistance to various diseases as well.

So it's amazing. We are only really just starting to understand the skin microbiome. It varies from region to region across our body. It's influenced by the much more famous cousin, the gut microbiome. Of course, we know a lot more about the gut microbiome. 

The skin microbiome and the gut microbiome interact, but it would be really great for the future of dermatology if we could harness the power of this natural ecosystem, and maybe think about treating skin diseases or preventing diseases by manipulating the microbiome in the skin. And also knowing what we can do to change it in terms of topical products or diet, or how do we actually get the best out of our skin microbes.

Jonathan Wolf: When I first started at ZOE eight years ago, there was still a lot of skepticism about even the gut microbiome really being very important, and I've noticed that the science on that has really developed a great deal over those last eight years. 

But there could be some bugs on our skin just because it's the outer surface, but they don't really matter very much for our health, right? They're just sort of landing there. 

Do we know whether it actually has any important role in our skin? 

Prof. John McGrath: That microbiome is established in early life. As soon as you are born, you will start to get a microbiome, and then it will become more established. It will change a little bit as you go through life, particularly during puberty, when you get new lipids, things on your skin.

But then in adult life it's fairly fixed. It will vary according to you have more moist or sweaty parts of your body, or drier parts of your skin, but it's relatively fixed.

As dermatologists, we would really love to be able to use the microbiome to treat skin diseases, such as dry skin or even conditions like eczema or psoriasis. But we don't have that power and knowledge at the moment. It's the future, I think. 

Jonathan Wolf: So you know, it's important, but at this point, there are no treatments that specifically understand how to support your microbiome or maybe repair it if it's damaged or something like that. 

Prof. John McGrath: I think we're at that stage of being curious about what's going on. There are some odd examples where manipulating the gut microbiome can impact diseases of the skin. 

And for example, who would've thought that changing part of your gut microbiome could make your hair grow back if you've got one of those autoimmune hair loss disorders?

Jonathan Wolf: So, hang on, you said that I can change my gut microbiome, and my hair might grow back. 

Prof. John McGrath: Yes, that's true, there's a very common autoimmune skin condition called alopecia areata, where the body develops antibodies that attack the hair follicles, and of course, conventionally and quite effectively, dermatologists will use steroids and other immune suppressing drugs to try and get rid of those antibodies and get the hair growing back again. 

But there are reports now coming out, and again, it's just a few reports, but changing part of the gut microbiome, for example, sounds a little bit obscure, but using a fecal microbiome transplant or fecal transplant can make your hair grow back again.

Shocking news, I guess. 

Jonathan Wolf: I think that's absolutely fascinating. 

So you're saying swapping out my gut bugs and suddenly I can get my hair back. Sounds crazy. And I love the way that science keeps figuring this stuff out. 

I know I pulled us off to talk about the microbiome, and I feel like probably we're going to talk a little bit about what happens as our skin ages.

Prof. John McGrath: Yes, that's right. I mean, classically dermatologists will talk about two sides of skin aging. 

One of them is the intrinsic aging, just old father time as the clock ticks by. And then the other one is extrinsic aging, which is to do with all those environmental triggers which might impact on the rate of aging.

So things like sunlight and smoking and pollution, and various other toxins that we might encounter. So those are the two aspects, and both of them can overlap, and both can contribute to the process we know as skin aging. 

What is aging? Of course, to many people, it's just the appearance of the skin. The skin becomes drier, it becomes a little bit more scaly. It can then start to get more prominent blood vessels in it. It can start to sag. It can start to become wrinkled. 

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I'm not doing a very good job of selling aged skin, I think, at the moment, but these are mostly the sort of disappointments that we have in life, of our skin just changing.

And we think, oh really? Is this what I have to cope with? And maybe that is what fuels people's interest and appetite for trying to do something about it. But these are natural processes. 

Jonathan Wolf: I mean, none of the things that you described are things that anyone wakes up and say, Oh, I'd really like to have more saggy and wrinkled skin.

Prof. John McGrath: Not attractive, is it really to most of us? 

Jonathan Wolf: And is any of that a cause of any ill health, or is this entirely superficial, and it isn't really causing anything that's going wrong? 

Or is this a sign that somehow your skin is not as effective as it is, as I think about my children?

Prof. John McGrath: If you just focus on the appearances, then you can think of it in fairly straightforward terms. It's just the appearances. 

But of course, there's a lot more things going on. We are accumulating damage in our skin as we get older, and some of that damage may not just be benign. It may start to promote the development of skin cancers, particularly in people with a paler skin.

So we are fighting this battle of the appearances, yes, but also this accumulation of damage, which can partly be repaired. But as we get older, our repair processes in the skin and in the body in general deteriorate a little bit. And therefore we have other aspects of skin aging, which can be more medical rather than just social, and their appearances.

Jonathan Wolf: John, why is it that my skin is starting to sag, that it starts to become more wrinkled? As far as I know, my heart is still doing a good job, and it's working the same way that it was, hopefully, when I was little. But clearly my skin is really changing, what's going on there that's causing that?

Prof. John McGrath: Again, just like the visible changes are there, there are all sorts of rather depressing changes going on structurally in your skin.

So you're losing collagen, your elastic tissue, which is important for the recoil in your skin. The stretchiness in your skin is losing its function. The fat that we have in our skin, 80% of your body fat is in the skin. But as we get older, it starts to redistribute, and part of that redistribution can affect the way the skin appears. 

Our bones change a little bit as we get older as well. So that can affect the overall scaffolding that we have in our skin. So each layer of the skin, from the outer epidermis through to the underlying dermis, where those collagens and elastic tissue are right down to the underlying fat and bone will be changing, remodeling, reducing in some of their vital components.

And that's part of the story of aging. 

Jonathan Wolf: That's really interesting. So one of the things you're saying that's happening is that I have less stretchiness because I don't have as much collagen as I used to have. Do we understand why that's happening? 

Prof. John McGrath: Well, collagen is produced by some cells in the dermis part of your skin called fibroblasts, and they produce a lot of the collagen in earlier life.

But as those fibroblasts age, they lose their ability to keep generating lots of new collagen fibers and the elastic tissue. The recoil is quite interesting because, what happens there, it's not necessarily just a lack of elastin. You can produce quite a lot of the elastic tissue, but it just doesn't work in the way it used to.

So skin will not stretch and recoil in the way that it did when you were young. So it's an accumulation of lack of some fibers and other fibers that just aren't working as well as they used to. 

Jonathan Wolf: And is everybody aging at the same rate and I asked that question sort of feeling pretty confident that it doesn't seem that way.

As I look around, I don't know the people who I went to school with and I'm now 50, what do they look like? I feel like there's a very wide distribution in fact, of how they appear to have aged. 

Prof. John McGrath: I think that's right. I mean, we wonder on one level, whether it's just the clock ticking all the time, but people do age at different rates.

And that applies to both their innate biological aging and also the way they look. So yes, everybody does differ in their appearances and their actual aging. 

Jonathan Wolf: Do we understand why skin might be aging at different rates, and therefore potentially can think about things we might do differently?

Prof. John McGrath: Partially, I think we've got some ideas about some of the processes. 

The genetics is important. We know that there are key factors that control our metabolism that will be important. Everybody's aware of antioxidants and the processes they do to try and mop up some of the damaging, chemicals that we have in our skin and other tissues, things that are called free radicals. So there are different ways of monitoring that damage that's building up. 

And it varies from person to person. Some people get a lot, some people don't get much, and there are already people doing things to try and impact on that, through things they might take in their diet, maybe things they might do in their lifestyle, other ways that they might influence the appearances, and that underlying ticking clock that we all have.

Jonathan Wolf:Let's say you're 50 or 60 or something. So you've been an adult for quite a long time. What are the key things in one's lifestyle that are likely to lead to faster skin aging than average? 

Prof. John McGrath: Yes. That's the challenge, isn't it? If we could just pick out all of those key factors and then say, yeah, stop those and I will stay young and look younger.

So what can we do? Are they the stories about things like sleep and hydration and stress? 

Maybe to some extent, but I think most doctors are going to focus on some of the things that may be relevant, like smoking and sunlight and maybe those are the bits that we can affect our lifestyle to try and influence a bit.

Jonathan Wolf: So those are having some real impact. If you smoke, it's not just a story; it is actually affecting your skin over time. 

Prof. John McGrath: So I'll give you a little bit of science on that one because what happens when you smoke is it activates a destructive enzyme in your skin called a matrix metalloproteinase.

So these are enzymes that will actually break down collagen fibers. So if you smoke, obviously it will do things in terms of nicotine, and some of the other potentially damaging agents in that cigarette. 

But it will actually, in your skin, activate matrix metalloproteinase, which will break down your collagen, produce wrinkly, sagging skin.

So if you do smoke, and you don't want to have wrinkles, don't smoke. 

Jonathan Wolf: What about vaping? 

Prof. John McGrath: Yes, I suppose that is slightly less studied. One looks that that might be a safer alternative, but I think you'll also find activation of these destructive enzymes from vaping, too. So there is no escape, don't smoke, don't vape.

Jonathan Wolf: So that's interesting. So you think that vaping would also have an impact on your skin? Because I think often I consider it something that's the safe alternative to cigarettes. 

Prof. John McGrath: Less well studied, less science, but potentially the same destructive effects might apply. 

Jonathan Wolf: So I think you're telling me this story, that it's sort of normal for my skin to age, but sadly, I haven't got as much collagen as my children, which I sort of know. But now you're helping to understand why it is that they're like, Daddy, your skin's a bit saggy, isn't it? My daughter said recently, I was like, thank you.

But there's this enormous industry that's trying to slow that down or even tell you that you can reverse the skin aging. So today I'd love to talk about like what actually helps with this and what is just hype. 

I have three myths that our listeners put forward as the things they were most interested in asking one of the world's leading dermatologists about. The first one was, expensive creams can erase wrinkles. So I see ads for them everywhere. Do they work? 

Prof. John McGrath: Well? That would be a wonderful thing if they did, wouldn't it?

Part of the challenge with all of these creams that you might see that claim to actually treat wrinkles is that they don't really. They are cosmeceuticals by and large. 

What is a cosmeceutical? It's not a drug, it's a product that's something that might impact on your skin. It sounds like a made-up word, which is partly cosmetic and partly a pharmaceutical.

But these are compounds that don't really have to prove that they work on the underlying problems in aging. They really just have to prove that they are safe. 

Now, some of them may have some benefit on the skin. They certainly, in terms of what they actually do to the anti-aging process, they work in the lab.

If you set up some amazing cell culture model or model of aging skin in the lab, and you test high concentrations of many of the ingredients of these anti-wrinkle products, they might do something. 

But then the reality is, when you make a product, is the concentration the same? And most importantly, can you deliver it to where it needs to be delivered in the skin?

I've already mentioned that the skin is a very effective barrier. If you are putting a cream onto the outside, then is it really going to penetrate right the way through the epidermis into the dermis to get down to where your sagging collagen fibers might be? Where it actually needs to do its effect, I suspect mostly not.

The other thing, just to mention about those creams, of course, is if you notice the advertising, they no longer claim to treat wrinkles or to improve wrinkles. 

The advertising actually now says ‘may improve the appearance of wrinkles’, which might tell you something, that you're having a more superficial impact, rather than getting really deep down to where the skin is contributing to actual wrinkles.

Jonathan Wolf: John, could you paint me a bit more of a picture? Because I can't tell my epidermis from my dermis.

I think, like everybody else who's actually thinking about buying these creams, I'm like, well, that makes sense. The wrinkles are on the surface, I put it on, Hey, presto, isn't it like builder's putty, just filling it all in and problem solved 

Prof. John McGrath: If only. That's right. So the epidermis is a brick wall on the outer part of your skin, and literally, that does not contribute directly to the appearance of wrinkles. 

What you have underneath are the collagen fibers, the elastic fibers, and these are the ones which are affecting the texture of your skin. So the epidermis over the top is really just like a protective barrier, a layer of carpet that's just over the top of your dermis where these destructive aging changes are taking place. 

So there are some changes in the epidermis as you get older, that contribute to dryness and so on, but really those things that we see as wrinkles are deeper down. And so for an effective treatment, you're going to need to be able to get down to those deeper parts of the skin. And topical preparations are not really going to get there in most cases. 

Jonathan Wolf: You're saying you've got this protective barrier, this epidermis, and basically I'm putting these creams on, and they're just preventing it getting through.

I'm thinking about it almost like the waterproof coat on my flat roof in the house. Is this sort of like, I paid good money to make sure the rain can't get through? And this is sort of what the outer layer of my skin is doing.

Prof. John McGrath: Absolutely. The skin is doing a good job. Of course, as we get older and it gets a little bit drier, maybe there are a few leaks in that particular taral in that you've got that are there. 

Jonathan Wolf: You're quite familiar with my flat roof. I can see. 

Prof. John McGrath: But mostly, of course, the skin will just do its job and keep the outsides out. 

What many of those products do, of course, is that they actually feel good on the skin, and there are some products which are cheap and cheerful, and others which are much more expensive.

And it's usually in those more expensive products, there is a particular preparation, the way it's put together, that actually makes it feel expensive, luxurious, and it ought to work, shouldn't it at that price?

Jonathan Wolf: So there is a real difference in feel, and that can be part of your experience to enjoy it, but it isn't necessarily going to change its ability to actually penetrate deep enough into the skin to have the impact on aging that you're looking for.

Prof. John McGrath: That's a very good summary. I mean, you, as the buyer, have to determine whether you think paying 200 times more for one of those more luxurious creams is really worth it. It'll make you feel better. I hope. 

Jonathan Wolf: I feel like we see more and more creams in white bottles with lots of scientific ingredients.

I feel like there's definitely been a shift where, despite what you're telling me, it all feels a lot more scientific than it used to. Is that true? And if so, what's going on?

Prof. John McGrath: Yes. You might think the marketing is very important in terms of how you package things and bottle things up. And one of the interesting things from some of my colleagues around the world, they investigated what sort of packaging are consumers going to be most interested in for skincare products?

And just to cite some research from colleagues in Thailand, they studied male toiletries, cosmetics, things that were to do with anti-aging, and they packaged them in all sorts of different bottles, formats, creams, and gels. 

But mostly the study was around the packaging, working out whether the color, the style of packaging really works. What they found, perhaps to people's surprise, because you might think, for male toiletries, cosmetics, something chunky, bold, silver, gray, graphite type of appearances might be most appealing to consumers.

Actually, they found that it was products in white bottles, white products, white tubes, where people sort of assumed some medical relevance or impact from these cosmeceutical products. So those were the ones with greatest appeal. 

So, packaging and marketing can contribute to the overall experience and expectation of what one might get from what's actually inside those bottles or tubes.

Jonathan Wolf: You're making me laugh because all the skin creams that have survived on my side of the bathroom are basically in white tubes, quite low-key. I'm just a victim of marketing like everybody else. 

Prof. John McGrath: You are indeed, Jonathan. There we are. 

Jonathan Wolf: So I just want to pick up on one other thing that you mentioned in the quickfire random questions, which I found very surprising.

I asked about whether they need to prove that these creams work before they're able to sell them. 

Prof. John McGrath: That's right. A cosmeceutical does not need to have scientific proof that it is actually doing something in the skin, which is reversing, or treating, or preventing some of the aspects of aging. And so most companies will actually just produce something that is safe. And then it goes back to the feel of the product and the consumer reaction to it. 

There are some cosmeceutical products in which the manufacturers, in collaboration with their scientists and dermatologists, have gone the extra step, and maybe have sampled part of the skin to look at some of the fiber changes that occur after placing products on the skin.

And they have demonstrated, at all be it low scientific resolution, some changes in the skin, that might show a slowing down or reversal of some of the aging products. So it's putting a little bit of proof into a story where it isn't actually required. 

Of course, for a consumer, you may take that and say, Wow, this is amazing. There is some science here. This must be a credible product. 

But it's unlikely to be anything like those studies I mentioned in the lab, where you can make a model of skin or use some cells and use a higher concentration of the active ingredients. There are limited data on this.

Maybe some products have a small amount of data, and the evaluation tools are not necessarily the ones that we would use in pure science. But, there's a small story for some of those products, and I wouldn't want to dismiss it completely. 

Jonathan Wolf: You're being very careful, John, I can hear. 

Last question around this. So you said that these expensive creams can't really erase wrinkles. I do definitely see ads where they sort of show a before and after of putting some sort of cream on and people say, Oh, you can't see as many wrinkles as before. Is that totally untrue? 

Prof. John McGrath: Not completely. 

But I would encourage everybody who looks at some of those adverts to look carefully at the before and after pictures and think, has the lighting changed? Is it more oblique? Is the photograph directly comparable? Is it exactly the same angle that's being shown there? Is the subject wearing different makeup? Are they wearing different clothes? Is there anything else to enhance appeal between the before and after pictures?

And if somebody calls their cream a creme, then probably you are more in the marketing sphere rather than anything more efficacious, but improves the appearances of wrinkles can take on many meanings and marketing opportunities. 

Jonathan Wolf: That's brilliant. I'd like to move on to the second myth, and we had so many questions around this.

The sun is the enemy, is I think how I would describe this in simple. What happens when sunlight hits our skin? 

Prof. John McGrath: So sunlight, as we know, is composed of lots of different wavelengths, and these will penetrate the skin. Many of your listeners will have heard of U-V-A, U-V-B, U-V-C, visible light, and all of these will have different penetration capabilities through your skin.

But ultimately, what they're doing is either causing damage to your genetic material, the DNA, or directly some of the structures and fibers in your skin. 

So it is an enemy on one level, but actually, in moderation, sunlight is good for you. There have been many epidemiological studies that show sunlight is really good for your heart. So, cardiovascular health can be improved by sunlight exposure. 

So that probably means next time you are not in the gym and you're lying on the beach and somebody phones you up and you say, just doing a bit of cardio. It actually may be telling the truth. So dermatologists always worried about DNA damage, about cancer, about moles turning malignant, what we call melanoma, and some other skin cancers.

But there are other clinical and human health issues that are beneficial. We all feel good, of course, because of the endorphins that sunlight releases into our skin. 

Jonathan Wolf: I was actually going to ask John, could you explain for a minute, how can sunlight be good for my heart? And in fact, then I'd love you to explain how sunlight can make me feel good. Because it definitely does. What's going on? 

Prof. John McGrath: So let's take the skin part first of all. So when you shine sunlight on your skin, it is damaging the DNA in your skin. So, tanning, I prefer the word DNA-damaging. So you are actually damaging the DNA.

But when you have damaged DNA, it will produce a chemical, which we call POMC, pro-opiomelanocortin. 

Pro-opiomelanocortin, POMC, is then broken down into various other sub-chemicals, some of which will stimulate the suntan, something called alpha melanocyte-stimulating hormone. 

But one of the other breakdown products of POMC, believe it or not, is beta-endorphins. Everybody knows about endorphins being a sort of stimulus to making us feel good, to feel better.

Exercise can stimulate endorphins, other things can stimulate your endorphins. Sunlight can stimulate beta endorphin in the skin. And maybe this is one reason why people like lying in the sun or going to tanning salons because you're becoming almost a natural junkie with your endorphin release in the skin. So that's why we feel good to some extent. 

In terms of your cardiovascular health. It's the chemistry, and the science is much more deep than that. You're controlling inflammatory chemicals called nitric oxide and other destructive antioxidant quenching as well can be useful. 

We don't know it for sure, but from population studies, we know it's good for your heart. You can save a lot of lives from cardiac ill health by having sun exposure. 

Jonathan Wolf: Do we understand how the sunlight is contributing to my heart health? Is it as simple as just, I definitely feel much happier on the days when the sun is shining, and somehow I'm just overall, it's reducing my stress, or is there something else going on?

Prof. John McGrath: There's going to be some science there. I think the simple way to think about sunlight is you have this double-edged sword.

When sunlight gets shined on your skin, it quenches various toxic chemicals that could be destructive to your general health, including your heart. So you have the benefits of quenching those damaging chemicals offset against that is the DNA damage in your skin, which could promote the acceleration and development of skin cancer.

So that's kind of the double-edged sword of sunlight, I think.

Jonathan Wolf: It's really interesting. So there's a sort of balancing act here.

Potentially, some of the messaging we've all been getting for the last 30 years of that all sun is dangerous because you're going to get skin cancer. There's also, you're losing out on some benefits, which you're talking about for heart health, or our mood, or the rest of it.

And so is it possible to have a middle ground? It's possible to have a situation where you shouldn't be avoiding sun all the time. 

Prof. John McGrath: That would be my recommendation. It's a question of just where you set that line, and it will vary from person to person. But I think an important message is that some sunlight is good for most people.

Jonathan Wolf: And when you look around, what most people might be doing in, you know, the Western world, whether that's, you know, the states or the U.K., or France, or whatever on most people protecting their skin. Enough from your perspective, too much or? Or not enough. 

Prof. John McGrath: If I put my dermatologist hat on, I would say probably not enough because it's really just the start of education for people, I think, in terms of how to look after your skin. 

People have been aware of this since the rising incidence of skin cancer in the 1960s and 1970s. People really started to understand that the sun wasn't always our friend, particularly when it was taken in excess. And gradually, different parts of the population around the world are getting the message. 

It seems that older men are still slow to get the message about protecting your skin health. But you know, in some countries around the world, New Zealand, Australia, the message has been there for 40 years plus, and people are sensible, take action, know what to do in terms of good behavior and bad behavior. 

I think it's important to keep the message going, that there are things we can do to look after our skin, to protect our skin, to reduce the incidence of aging and skin cancer. But at the same time, all of us need to enjoy a bit of sun every now and again.

Jonathan Wolf: Now, you mentioned in the quickfire again, something that I was very surprised by. Because you said that it was possible for those of us who might have been in the sun for too long and got sunburnt, there might be some way to reverse it. 

I'd always assumed that that was an old wives' tale. And if you were burnt, you were burnt. It's possible to do something about this. 

Prof. John McGrath: Yes. I mean, this is not mainstream science at the moment, but what we have are some new ideas about treating sunburn. 

None of us should really get sunburnt. We should all be sensible, shouldn't we? But what tends to happen is that people will go out on the beach, maybe it's a nice day, maybe they'll stay there too long, and then come the evening, people will think, oh no, I've overdone it. 

My skin's going red. I'm going to have a terrible night. It's going to be blistering. I'm going to be peeling, I'm going to be agony. The rest of my holiday is ruined. Where's the doctor? What can I do? I haven't got any aloe vera or something like that to put on my skin. Can I get some steroids of some sort to calm it down?

Jonathan Wolf: So John, you've painted a beautiful picture. I'm going to really tease our listeners because I want to come onto my myth number three before we tell the answer, because I know you're going to give us actionable advice. 

You're going to tell us the answer for what to do in that horrible situation. 

Prof. John McGrath: Yes. Hang on in there. I'll tell you the answer soon. 

Jonathan Wolf: We don't normally do this. Let's see what the feedback is. 

Because I would like to go on to myth number three before we switch to really all the actionable advice. It's interesting, we had a lot of questions about this, and I feel it's a topic that five years ago I hadn't really even heard about. 

It's collagen powders. So we had lots and lots of questions, which were all basically the same. Which is, is it true that collagen powders, you know, if I eat them, drink them, can sort of plump my skin from the inside out? 

Maybe start with the theory of how they should be doing this, and then tell me, does it work?

Prof. John McGrath:  So the challenge, of course, is that people think that what happens when you age is that you lose collagen in your skin.

And most people will think, well, if I lose collagen, can I just replace collagen, and how do I replace collagen? Ah, there are these supplements out there. It says collagen. Is it just a question of taking something from the pot and putting it into my skin? That would be really great if that happened.

But it makes no sense for us as doctors and scientists because this collagen protein, what happens, you take it by mouth, it goes into your acidic stomach, and it's into what we call the digestive system, and that's exactly what it does.

It digests this complex polypeptide protein into individual amino acids or tiny little peptides, and many of those will then be absorbed somewhere through the gut, and they will contribute to the protein diet that you are taking. 

What's going to happen to them? Can we really expect those little individual amino acids, peptides to know what to do? Are they really going to go into your bloodstream, circulate around, and think, ah, this is a nice place? The skin where there's missing collagen, let me land here, and start assembling myself into a collagen fiber to replace what is missing. 

It just doesn't seem logical, and there is no science to support that idea at all. There may be some types of collagen where people have a little bit of evidence. I see no proof. 

Of course, what they can do, is if you're taking a protein diet, some of it may finish up in the skin. Some of it may complex into bigger protein structures. Some of those may then absorb water or contribute to increased hydration in the skin, which might give a plumper appearance.

So it might improve some of the appearances. But actually, we should dispel this myth that a collagen supplement will lead to more collagen in the skin. That simply cannot be true. 

Jonathan Wolf: That was pretty strong. Because you know, people are selling these, they're expensive, so people are choosing to do this versus buy something else, maybe, a better diet.

You sound like you really just believe this is junk and doesn't work. 

Prof. John McGrath: I will believe good science when I see it. As I mentioned, maybe there's a little bit of something around some of those marine collagens, but it's not great restorative, anti-aging, new skin dynamism type of results. 

I think it's safer at this stage to say, case not proven, and just be careful if you go out and think about buying some of these collagen supplements, because very little of it, and perhaps none of it will finish up in your skin.

Jonathan Wolf: You've been a bit tough on the myths, so I'd love to actually talk about what people can actually do if they want to keep their skin both as effective as possible, because you've talked about how important it is as this barrier, but also hopefully, looking as young, as possible. 

I think the obvious place to start is skincare routine. Should there be a daily skincare routine, and if so, what really should be in it? 

Prof. John McGrath: There is such a thing as a good skincare regime, and it's typically divided up into three bits, and most dermatologists will give similar advice. The first one is about cleansing and what sort of thing you do to cleanse, and there are a whole range of cleansers out there.

Jonathan Wolf: For those of us who are quite naive on this, what do I need a cleanser for? 

Prof. John McGrath: Well, just to get rid of any dirt and grit and dead skin on the surface that you may have accumulated over the previous few hours.

It just removes some of the products there. I think most people will just probably use something in the shower or a quick wash in the basin, but that still constitutes cleansing to some extent.

But there are a number of products which are out there as cleansers, right? 

Jonathan Wolf: But you're not sitting here saying, oh, that's all a bad idea. I'm stripping my skin of what you shouldn't do. Actually, cleansing gets a thumbs up? 

Prof. John McGrath: Cleansing of some sort is probably a good idea for most people. 

And then the second stage, after that, is around moisturizing. And this is again, a little bit contentious, because some people just don't need a moisturizer. But probably about two-thirds of the population would benefit from putting a moisturizer onto their skin. 

Choose one that's more creamy, perhaps, than greasy. Particularly if you have a spot or acne prone skin. Grease can make things worse, and nobody wants to look ultra shiny after putting that on. 

But some moisturizer may be helpful after that cleansing, particularly as the cleanser may dry the skin to some extent. 

Jonathan Wolf: And John, what does a moisturizer do? 

Prof. John McGrath: So it's just providing some hydration to the superficial part of the skin. Again, it's not penetrating; it is just providing you with some lipids or some other related moisture-retaining compounds on the surface to improve your appearance of your skin, to maybe reduce the amount of water loss that naturally occurs through your skin, and to deal with any dryness that might be there.

So it can be a good idea, and it's a very personal choice about what moisturizer you use. Sometimes, some of the cheaper products are just as good as some of the more expensive ones. So moisturized would be phase two. 

Then, the next phase I think that dermatologists will lobby hard about is the sunscreen. And it is a good idea to put sunscreen on. How to do it, what to choose. These can be personal choices, but most dermatologists would recommend you don't use a sunscreen with a low sun protection factor. 30 plus is the minimum that most dermatologists would recommend. Sometimes 50-plus.

When you look at the label on it, look for something that gives ultraviolet A, UVA protection as well. And on most sunscreen products, there's a little logo, it says UVA in a circle. And that's something to look at. So you're looking for something factor 30 plus with a UVA logo on.

Then it's important to think how much do I actually put on? Well, if you are putting on your entire body. Obviously, most people won't be doing that because they'll be dressed and ready to go, but if you were to cover your entire 1.8 square meters of adult skin.

Jonathan Wolf: What's that? That's like 10, 12 square feet? 

Prof. John McGrath: Yes, it would be quite a lot, wouldn't it really? Then you would need at least six teaspoons worth of sunscreen. Another analogy people sometimes think is a shot glass full of sunscreen. That would be enough for one application of sunscreen.

Jonathan Wolf: Which is quite a lot of sunscreen, isn't it?

Prof. John McGrath: Yes. Because I think one of the big problems we have, you look at something, it says SPF 30, SPF 50, or something like that, but actually, how those numbers were calculated is quite different from what we do in practice.

So those SPF numbers were calculated in a laboratory by putting a certain amount of sunscreen onto a square centimeter or quarter inch of skin and shining light on it, and then generating numbers and showing what an SPF can mean in the lab.

But actually, none of us, myself included, ever put sunscreen on as thickly as it was done in those laboratory calculations. 

Jonathan Wolf: Is that right? It's put on really thick to show you that it works really well. And then in reality, we just put like a little dab. 

Prof. John McGrath: It's a standardized laboratory approach, but we actually just dab and smear, don't we?

And that comes onto the next point of sunscreen application, is that you should really try and think about putting it on repeatedly throughout the day. 

Every two to three hours is a good idea. So, once before you dash out of the house is not enough. Every two to three hours, you should be thinking about putting your sunscreen on.

And that is a good regimen. Cleanse, moisturize, sunscreen, and you're done. 

Jonathan Wolf: Can I ask about the sunscreen a little bit more? Because you just talked also about the balancing factors between the risk of cancer on one side, and some of these other benefits. 

So maybe my first question is, is the only benefit of sunscreen to avoid the risk of cancer, or does it also help against some of the skin aging that you've been talking about previously?

Prof. John McGrath: Both. So sunscreens will protect you against both aspects of that type of problem. So the aging aspects, and also the malignancy, the cancer risk that everybody can experience with sun exposure. So a double hit. 

Jonathan Wolf: Is aging only about this damage to collagen, or is there other things that are going on?

Because I definitely see this, I definitely notice I'm old enough now to notice that friends of mine who really love the sun, definitely look older today than those who have had what I now consider a Japanese attitude to sun.

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I say that because I went to Japan once on holiday. I had a wonderful time, and I was really struck by the fact that we were on this trip with quite a lot of Japanese people.

And certainly all the women basically had an umbrella in the sun over the head as we walked around to make sure they didn't get sun on their face, which I guess is even better, presumably than wearing SPF. 

So I consider that the extreme. I definitely feel like I've noticed a difference in the visible aging, but I realize that's not a scientific experiment.

Is that real, or am I just sort of putting things together in the wrong way? 

Prof. John McGrath: No, you're right. And in fact, many of those people in hot countries in Asia, for example, will be putting sunscreen on as well as using some sort of protection, and a UV umbrella is what they tend to go for. 

I grew up in Japan myself, so maybe as there is some legacy for me too. But for most people, I think the idea should be when should you start putting sunscreen on?

Obviously, if you're going on holiday as a child, that's fine to put your sunscreen on, but those regular sunscreen applications, mid twenties, early thirties, is probably when you should start doing that regular everyday sunscreen application. 

Jonathan Wolf: That's interesting because I feel like one of the things that you are most taught to do is put sunscreen on your children when they're little.

And yet you're saying, actually, I shouldn't worry about that as much. 

Prof. John McGrath: Oh, if they're going on holiday or they're going outside a lot, yes, but if they're just running around, let them have a little bit of sunshine. I don't see any problem, but do stop them getting burnt. 

Jonathan Wolf: So it's more like, if it's really sunny, and they're going to be out all day, then sunscreen is a good idea, even if they're five or 10.

But if it's not particularly sunny, they're not going to get burnt. You're saying you probably don't need to worry so much. 

Prof. John McGrath: Worry less, I would think. 

But obviously, you do need to think about clothes. You need to think about the amount of time that kids are spending out in the sun and avoid them getting burned.

But what we're really saying about the regular sun application is part of this cleanse, moisturize, and apply every day approach from your mid-twenties onwards. 

Jonathan Wolf: We are recording this podcast in London and England. It's very gray and wet outside right now, and for much of the winter, it's pretty dark.

Do I need to wear sunscreen on my face every day or only in the summer when there's more light around? 

Prof. John McGrath: This is going to vary from country to country, of course, but as you say, we're in gray, rainy London. 

If you look at where the sun sits in the sky and the potential damaging rays, I think, Jonathan, we can let you off between November and March, as long as you're not disappearing off for a sunny holiday somewhere in between.

But the sun is so low at that time, and the number of rays that are coming through and potentially damaging the skin is low. So even I will give it a rest between November and March. 

Jonathan Wolf: I think it's really interesting. Do you feel that as a dermatologist, your advice on this is less absolute than it would've been 20 or 30 years ago?

I feel like I've been hearing slightly more balanced advice about this than maybe I was getting in the past.

Prof. John McGrath: I think that's right. All dermatologists will focus on not letting kids or adults get burned, but a little bit of sun exposure is good for you. 

Common sense and regular applications of the sunscreens is also common sense. So it's this balanced approach to life. Nobody wants to stop people enjoying the sun, but we have to take a sort of sensible attitude.

And I think a lot of people have taken that on as part of their regular lifestyle. Now they know the sun is both wonderful and potentially harmful. 

Jonathan Wolf: What about if I didn't put my sunscreen on and I lay out in the sun in Florida all day, and now I've gone a beautiful lobster and it's starting to hurt.

Obviously, I should have worn the sunscreen. That's very clear. I've heard it loud and loud and clear, but if I didn't, you said there might still be something I can do. 

Prof. John McGrath: Yes. I'm reprimanding you for that behavior, Jonathan.

So that's it. You're sitting there and you've gone red, and you're going to blister, and you know, the next few days are going to be really very uncomfortable, and there's not much you can do about it. 

Or is there? I guess before we get to that, we probably ought to think what has actually happened in your skin, Jonathan, now you've been lying on the beach, so you have got this red skin and what's going on in your skin. 

If you could put a microscope into your skin, you would see inflammatory cells, cells called macrophages and neutrophils would be starting to come into your damaged skin. 

They would be releasing lots of inflammatory chemicals, one called TNF-alpha, tumor necrosis factor alpha, that would be starting to be expressed in your skin. This would cause your blood vessels to dilate and leak, and other inflammatory cells would be recruited. 

You'd be activating other pathways in the skin, which could be potentially damaging nitric oxide synthase. All of this damage is starting to go on this raging inflammation that's going on in your skin.

In fact, one piece of recent research that some of my colleagues in the U.S. have helped generate is to show that single high-dose vitamin D3 can do amazing things in restoring your damaged skin. 

So, how does it work? Well, vitamin D3 is something that will activate directly on inflammatory cells in the skin called macrophages. It turns them from pro-inflammatory to anti-inflammatory. It calms down the other neutrophils, the chemicals that are driving this particular inflammation. 

So it has direct anti-inflammatory effect. It's nothing to do with being a vitamin that will actually impact your bone health or anything. We're using it as an anti-inflammatory approach, but we're not talking about the same dose that you might do for a supplement that somebody might take every day. What we're talking about here is a single high-dose treatment, where you can actually switch the fate of these macrophage inflammatory cells.

Most importantly, by the following morning, your skin should be pretty much back to normal. No steroids, no aloe vera, no other chemicals at all, just the simple anti-inflammatory effects of high-dose vitamin D3. 

Don't worry about your calcium levels, your phosphate levels, because your kidneys will protect you against all of that. The benefits are directly onto those inflammatory cells, and it helps, and it will actually improve your skin, and you'll be ready enough to have a second day in the sun. 

All be it this time. Jonathan, I think with applying some sunscreen, 

Jonathan Wolf: Firstly, the description of what happens is rather terrifying when you burn yourself. Secondly, this sounds magical. 

I guess two practical questions. What is a high dose? Are there any risks? Because I know we've done a couple of podcasts around vitamins, and one thing I discovered from that is that ultra-high levels of vitamins can actually be dangerous, which shocked me. 

Prof. John McGrath: Yes, I think that's right.

So, a caution about vitamins, many vitamin supplements, and many doctors will question whether they do any good at all for people's health. 

But you're right, there are some vitamins which are fat-soluble. Vitamins A, D, E, and K are fat-soluble, and potentially, you could build up high levels of those.

But we're talking about a single dose. Now, the supplement dose that most people take is something like 1000 international units or 25 micrograms. So that's the same. 1000 international units is 25 micrograms. 

The dose we're talking about here for sunburn is something like 50 times that. Maybe a hundred times that. So, 50,000 units, international units of vitamin D, would be a useful place to start.

Many of us would recommend taking a hundred thousand units, just as a single dose, and this could be taken anytime between one to 12 hours after the sunburn. So that would be the effective window of taking this single high-dose vitamin D3. So that's the high dose. 

What about the safety of this high-dose vitamin D3? There is no need to worry. As I mentioned, your kidneys protect you from surges in calcium and phosphate. No other potentially adverse effects have been demonstrated. You know, there are other medical indications that we use this for beyond sunburn, but in terms of sunburn, this is a very useful thing to do.

So I think what I'm hoping you will do, Jonathan, for your holiday, is pack your SPF factor 50. But alongside that, maybe you'll also pack some vitamin D3 that you've picked up at the health food shop. That would be a good combination to take, but please don't burn yourself. 

Jonathan Wolf: Brilliant. And presumably you shouldn't do this if you're not healthy. So you're saying it's fine if your kidneys are fine. 

Prof. John McGrath: There may be some caveats and and it may be worth taking some additional medical advice, but for the vast majority of people, this will be a great remedy for your acute sunburn. 

Jonathan Wolf: Now, I think we talked about actionable advice in terms of sort of cleansing and moisturizing and sunscreen. The one product I haven't heard you talk about, which comes up a lot, is retinol. 

Could you start by saying what retinol is, and then tell me your view about whether or not there's something real and actionable that you can do there? 

Prof. John McGrath: Yeah, so retinol is a derivative of Vitamin A. It's part of a group of compounds that dermatologists use in their practice called retinoids.

Many listeners will have heard of retinoic acid, which we can use as dermatologists in either cream or gel form, and apply to the skin for acne, for aging, and anti-aging effects as well.

Retinol is another version of that, which is not necessarily requiring a prescription. It's something that is in a lot of products can be bought over the counter and may have some of the same benefits as retinoic acid.

So it is something which can have anti-inflammatory effects on the skin, and may have some benefits for improving the appearance of aging, and maybe even reversing some of the effects of aging. 

So it's out there in products and something that people can apply off-prescription. 

Jonathan Wolf: And so there, unlike some of the things you were talking about before, like the collagen powders, the sort of real science behind this. This actually does something. 

Prof. John McGrath: I think so. Because what most of us do in dermatology is to look at the literature and see what sort of clinical trials or comparative studies have been performed. 

We know that there is a 60-year history of retinoic acid being used for anti-aging and acne, and other dermatological indications, but we know that there have been comparative studies using retinol to ask the question: is it similar to retinoic acid, or is it more effective? Is it less effective? Does it have similar side effects? Different side effects?

Most of us then will look at the information. And in the literature, there are a number of well-detailed studies, which we call systematic reviews, where people have actually gone through thousands of scientific papers and studies, filtered them to get only the most robust findings out, analyze those studies, and then made some conclusions.

Those conclusions suggest that retinol can be as effective as retinoic acid. In some studies, it can cause less side effects like dryness or irritation, and it can have some anti-aging properties. But at the same time, there are also some other studies which show that it is less effective than retinoid acid and may not have much benefit at all.

So even the robust studies are giving us some slightly conflicting data, but there may be benefits to using this vitamin A derivative, retinol. 

Jonathan Wolf: You're saying it's not as strong maybe as the retinoic acid that you're going to get prescribed by your dermatologist. Is that what I'm understanding?

So it's a sort of like a weaker version that you can get off the shelf, and that hence you are being a little bit more cautious. 

Prof. John McGrath: Yeah, so the percentages of retinol, just like they can for retinoic acid in any product, can change, and that will alter some of their effectiveness in terms of what they're being used for.

But usually retinol is a better-tolerated, a less irritant product than retinoic acid. And it may have some of the same benefits. 

Jonathan Wolf: And we had quite a lot of questions about at what age someone should start using retinol, and this discussion about the fact that there's this huge growth in using all sorts of skincare, even amongst early teenagers or younger, because what they're seeing on social media.

What are your thoughts here? 

Prof. John McGrath: For retinol, it's probably the same sort of story. 

Mid twenties, early thirties would be a reasonable sort of time to start thinking about it. I have dermatologist colleagues applying retinoic acid or retinol onto their skin for 30, 40, 50, 60 years, and they have beautiful skin, almost wrinkle-free skin. 

But small price to pay, I think, I suppose, or maybe it's a big price to pay for having to do that on a regular basis.

Jonathan Wolf: And would you have any concerns about applying it if your skin were, if you were 12 years old? 

Prof. John McGrath: Yes. I wouldn't advise applying retinol at that age. I think that children, teenagers, young adults, should really avoid all of these products on their skin. 

We've mentioned that some of those other skincare routines need to kick in much later. So I think it's an important message for anybody who's really maybe under the age of 25, is don't be taken in by a lot of advertising, by a lot of social media trends as well. 

You don't really need to be doing a lot of things to your skin at that age. You are in a wonderful time when your skin can just work at its best and do great things for you. So don't spoil it, don't damage it. Just let it be. 

Jonathan Wolf: And if there's parents listening to this, I'm probably maybe in that group that worry that potentially this might cause harm. So it's not just that it's a waste of money, but actually it might actually be harmful. 

Can they relax, or are they right to worry about this?

Prof. John McGrath: Most of the time it won't do any harm, apart from probably to the parents' wallet, I think, or credit card. But to the kid themselves or the young person themselves, I don't think there'll be any sustained benefit. But there may be peer pressure, there may be social media pressure. People may need to try things.

But if you are in a position just to say no and forget about it and just get on with life, then that would be a much better option for you.

Jonathan Wolf:  Brilliant. We haven't mentioned anything about nutrition. Is there any food that I could add to my diet tomorrow that could actually have an impact on my skin? 

Prof. John McGrath: It would be wonderful, and there'll be many listeners hanging on to see what is going to be recommended at this stage.

Or is it going to be the usual thing of talking about oily fish, nuts, and seeds, fermented products, leafy green vegetables? Probably it's going to be more of the latter in terms of where we are.

For your skin, it's the same sort of trends that go through avocados, cucumbers, other types of product may be there. And some of this may be just be driven by social media rather than science. 

There are many fruits out there which could have remarkable effects on the skin, but I would probably be guilty by promoting one or more of them. 

But we could start a trend. Maybe Jonathan, let's say I'm quite interested in the gac fruit, G-A-C, because it is incredibly high in some amazing chemicals called lycopene, which will protect you against the sunlight, and it's very high in beta carotene, which will mop up various free radicals in your skin. 

The gac fruit, also known as a baby jackfruit, is amazing in terms of its potential, and there are people across Southeast Asia who are using it all the time in their cooking and so on, but it's not really out there at the moment.

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But maybe we can set a trend and say that fruit, that food that will give you the anti-aging properties, could be gac fruit, but it might be something different next week. 

I think the good advice that ZOE has given around a healthy diet for your gut can also apply to your skin as well. A varied diet, a mixed diet, but stick to the oily fish and the grains, the fermented stuff, and the leafy green vegetables, and your skin should at least show some improvement.

Jonathan Wolf: John, that was fascinating. We covered a lot. I'd like to try and do a summary. 

The thing that immediately comes to mind is this idea that we can all be natural junkies by just lying in the sun, because the sunlight goes onto our skin, it starts damaging the DNA, which sounds bad, it's going to make me look old and wrinkly and maybe get skin cancer, but it can produce this chemical, which you call PMOC, and that then gets broken down and gives me endorphins.

So basically I could do something really hard, like run a marathon, or I could just lie in the sunshine and I get this natural high. And this is part of why we all love it when the sun comes out, and suddenly we get the sun on our skin. And did I get that right? 

Prof. John McGrath: Absolutely. You're a convert to that story.

Jonathan Wolf: I love this idea that now the science understands what's going on. 

What you said, though, is it isn't just about feeling good. There's actually real evidence that this helps our heart health, and that the sunlight we can also see is quenching these toxic chemicals.

So we talk a lot about fighting inflammation on this show, and it sounds like you're saying the skin itself has this role if it gets the sunlight on it.

We've all heard the story that sunlight is bad for you because it causes skin cancer. And I know that's very serious, and people die from it. But you're saying there is also these benefits, and so we now need to think a bit more in a balanced way between those. 

The other thing that I, of course, picked up on is that the skin microbiome is real. You said there are billions of these bugs and that although we're only just starting to understand it. We might be doing this show in 10 years' time and really talking about ways to treat people specifically. 

Then we started talking about all of these myths, and my big takeaway was that my skin is a really good barrier. And you talked about this thing being the epidermis. And I think about it as being almost like this waterproof layer, like I might put on my house.

So, pretty much the creams that you put onto your skin can't really get below that. So, actually, most of their claims you have to treat with a grain of salt, probably can't really work just because they can't get down to where they need to. 

What I understood is where they really need to get to is into this collagen. Sadly, I have less collagen than I did when I was younger. This is why my skin is starting to look saggy and more wrinkles. 

There are lots of ways to make the collagen worse. So you said, too much sunshine, smoking or vaping, it sounds like a really bad diet wouldn't help.

Unfortunately, just popping a collagen pill isn't going to fix this. So that was definitely thrown out with the myths. 

Similarly, there isn't some magic cream that's going to fix it because actually it's more that they do clever things with their advertising than that actually it breaks through this epidermis and gets to where the real wrinkles are.

Prof. John McGrath: Perfect summary. 

Jonathan Wolf: What you did say is there is skincare routine that matters. So cleansing is a good idea, get the dirt off your skin. Moisturizing, I think you said two-thirds of us would benefit. Make sure you choose something that's more creamy than greasy, because that hydration matters.

Sunscreen, despite the discussion before about how a bit of sun is good, we had a very long discussion about putting lots of sunscreen on. So I think you're still allowed to be a dermatologist. And you said 30 plus is minimum. Make sure it protects against UVA. 

But interesting you were saying, think about this, if you're into your twenties or your thirties, if you're younger, then certainly you shouldn't be worrying about putting retinol on. 

But also, you're saying, don't be completely paranoid about the sunscreen. There's benefits to the sun as well. So, if they're at risk of getting burned, put it on. But otherwise, you don't need to worry as much. 

You said if you live somewhere that is cold and dark, so that's London or Canada or wherever, then actually in the winter months, you probably don't need to wear this sunscreen.

So you said, in London, from November to March, I could actually be allowed not to put it on. 

Then the final thing, which I'm sure anyone listening to is really struck by, is if you do get burnt, there is something you can do. You can take this super high dose of vitamin D3, I think I wrote down 50,000 or even a hundred thousand international units, fast, within 12 hours.

And you wake up the next day, and you're all fixed. 

Prof. John McGrath: Try it and see. 

Jonathan Wolf:  Wonderful. See you next time.