Some things look the same but generally it's hazier

sometimes light and dark are flipped

skin looks blotchier and fake teeth stand out

Whoa!

Smile for me

Oh my goodness

Are my teeth black?

Do you have a fake tooth baby?

--Yes --Which one?

but the idea for this video started a long time ago with a question I had which is,

How does non ionizing radiation like ultraviolet light

like ultraviolet light damage skin and lead to cancer?

I do like to tell people that if you want to see how good your skin could look,

look at your butt

because that's an area that doesn't get sun

and even old people have perfect butts

it's how your skin would age without the sun

when I thought about what UV light must be doing to our cells and our DNA,

I imagined it would be getting in there and breaking all these bonds and that would be the problem

but in fact it's kinda the opposite

UV actually facilitates the formation of covalent bonds in our DNA that shouldn't be there.

It comes in and it kind of creates these unauthorized bonds between the bases

called pyrimidine dimers

instead of having them bonded across it bonds the one next to each other

if that makes sense. -- Oh. -- Yeah.

so what happens is two thymines, which are side be side,

can actually get covalently bonded together

and that creates a lesion on the DNA you can think of it like a little bump

that makes the DNA hard to read and work with

That's not enough in itself to cause skin cancer. If that were the case we would just be covered in skin cancers

then the next step is that we have to repair it

and in the repair,

that's when you form mutations that could eventually lead to cancer through a bunch of different pathways

and there's actually people who have specific

genetic issues that they can't repair these issues and they are covered in skin cancer

UV has other effects on the body like

suppresses the immune system so, as Haley says, it's a "double whammy"

There's also kind of a double whammy because UV not only induces these unauthorized bonds

it actually tamps down our natural immune system

so one of the best ways we fight cancer is through our immune system

we have constantly need surveillance through our skin

so not only is sunlight creating these problems,

It's actually reducing our ability to fix them.

So unfair

UV light also causes us to visibly age. It's called photo-aging

I should clear up a misconception here that I had which was, I thought glass blocks all ultra-violet light.

so I thought if you're inside a car, for example, you really don't need to put on sunscreen because,

you're not being exposed to UV light

The car does not block UVA. It's glass

It does block most UVB

but you're still susceptible to those sunspots and those wrinkles through the glass

and a lot of my patients if you look and you compare their hands,

the left is is more wrinkled or has more sunspots on it because they're driving.

So they're sticking that hand... --Sticking that hand out their truckers. Absolutely you can see it the worst

And there's a really famous picture of someone whose left side of their face

is significantly more, as we'll call photo-aged, or old-looking, than the other side of their face.

So that's mostly UVA and UVA, as I said, it's a longer wavelength, penetrates a little bit deeper.

so wrinkles mostly come from destruction of our collagen and elastin

which is natural fibers that hold up the scaffolding of our skin

so with age the cells that secrete collagen

they're called fibroblasts they stop producing as much

and what the Sun does is it breaks down the existing collagen and elastin we have

so fibroblasts really like to be stretched, they like to be pulled and collagen does that, that collagen matrix

so the Sun damages the collagen fibers leading to less stretch on fibroblasts

and less production of collagen

which means that you look a little more saggy

I know it's very depressing so sun protection helps the degradation of those collagen and elastin fibers

You know there are a lot of creams on the market that claim to be anti-aging

but the one that really works

is sunscreen

preventing ultraviolet light from hitting your skin is the best thing you can do

to avoid skin cancer and to avoid photo aging

So yeah. It's good advice. Use sunscreen.

hey I'm on set for Jurassic world fallen

Kingdom and I'm here filming sci-fi test

lab where we try to recreate some

dinosaur parts out of machinery and test

them out so if you want to see that then

click here