I sunburn super easily.
I sunburn super easily.

It just takes a few minutes sitting in my garden or on a beach, and then a couple days
It just takes a few minutes sitting in my garden or on a beach, and then a couple days

later my skin starts peeling off.
later my skin starts peeling off.

It’s seriously pretty gross—not exactly the effect most people go for when they sunbathe.
It’s seriously pretty gross—not exactly the effect most people go for when they sunbathe.

But, what really happens when you get a sunburn?
But, what really happens when you get a sunburn?

I’m Anna Rothschild, and this is Gross Science.
I’m Anna Rothschild, and this is Gross Science.

Most burns occur if you come in contact with something hot, like when you scald the roof
Most burns occur if you come in contact with something hot, like when you scald the roof

of your mouth on a slice of pizza.
of your mouth on a slice of pizza.

But sunburns are actually not caused by heat.
But sunburns are actually not caused by heat.

Sunlight is made up of a bunch of different types of radiation.
Sunlight is made up of a bunch of different types of radiation.

One of them is infrared radiation, which is primarily what makes sunlight feel hot.
One of them is infrared radiation, which is primarily what makes sunlight feel hot.

But there’s also visible light, which allows us to see sunlight, and then there’s ultraviolet
But there’s also visible light, which allows us to see sunlight, and then there’s ultraviolet

radiation.
radiation.

Ultraviolet, or UV, radiation is what causes a sunburn.
Ultraviolet, or UV, radiation is what causes a sunburn.

It can wreak havoc on skin cells by disrupting important molecules, like DNA.
It can wreak havoc on skin cells by disrupting important molecules, like DNA.

So, your body does its best to protect you from it.
So, your body does its best to protect you from it.

When UV radiation hits your skin, pigments called melanin absorb it, and shield your
When UV radiation hits your skin, pigments called melanin absorb it, and shield your

DNA from harm.
DNA from harm.

Now, melanin is present in our skin cells all the time—it’s what gives your skin
Now, melanin is present in our skin cells all the time—it’s what gives your skin

its particular color.
its particular color.

It’s created by special cells called melanocytes, which then distribute the melanin to other
It’s created by special cells called melanocytes, which then distribute the melanin to other

cells called keratinocytes.
cells called keratinocytes.

Those are the most common cells in your outermost layer of skin.
Those are the most common cells in your outermost layer of skin.

When your skin is exposed to UV, the melanocytes ramp up their melanin production, and also
When your skin is exposed to UV, the melanocytes ramp up their melanin production, and also

transfer more melanin to the keratinocytes.
transfer more melanin to the keratinocytes.

This happens to varying degrees based on your genetic makeup, but that’s why your skin
This happens to varying degrees based on your genetic makeup, but that’s why your skin

might turn darker, or tan, if you’re out in the sun for a while.
might turn darker, or tan, if you’re out in the sun for a while.

But, the melanin defense is far from foolproof—regardless of how dark your skin is, or how much you
But, the melanin defense is far from foolproof—regardless of how dark your skin is, or how much you

tan, some UV rays can sneak past.
tan, some UV rays can sneak past.

And when they do, they can damage your DNA.
And when they do, they can damage your DNA.

This can actually happen in a few different ways.
This can actually happen in a few different ways.

Sometimes the radiation will directly zap your DNA, damaging it in just a trillionth
Sometimes the radiation will directly zap your DNA, damaging it in just a trillionth

of a second.
of a second.

Alternatively, UV rays can do something more sinister—they can actually turn your melanin
Alternatively, UV rays can do something more sinister—they can actually turn your melanin

against you.
against you.

The radiation can make your cells produce these harmful molecules called free radicals.
The radiation can make your cells produce these harmful molecules called free radicals.

Now, this is a little bit complicated, but essentially the free radicals excite an electron
Now, this is a little bit complicated, but essentially the free radicals excite an electron

in your melanin.
in your melanin.

The melanin then bumps into your DNA and excites an electron there—which can cause the DNA
The melanin then bumps into your DNA and excites an electron there—which can cause the DNA

to kink.
to kink.

Regardless of how it happens, once your cells are damaged they start producing warning molecules,
Regardless of how it happens, once your cells are damaged they start producing warning molecules,

signalling that something bad is going on.
signalling that something bad is going on.

If enough cells produce the signal, your body will mount an inflammatory response, sending
If enough cells produce the signal, your body will mount an inflammatory response, sending

lots of different types of blood cells to the area to stop and repair the damage.
lots of different types of blood cells to the area to stop and repair the damage.

And it’s this influx of blood that causes the redness you typically see with a sunburn,
And it’s this influx of blood that causes the redness you typically see with a sunburn,

depending on how light your skin is.
depending on how light your skin is.

So, what about the peeling?
So, what about the peeling?

Well, your skin cells are shedding all the time without you noticing it.
Well, your skin cells are shedding all the time without you noticing it.

You actually have stem cells in your skin that live for decades.
You actually have stem cells in your skin that live for decades.

The stem cells produce layers of keratinocytes, which fall off and are replaced over time.
The stem cells produce layers of keratinocytes, which fall off and are replaced over time.

But those keratinocytes don’t mature properly when they’re damaged by UV.
But those keratinocytes don’t mature properly when they’re damaged by UV.

So instead of flaking off inconspicuously, they all clump up and peel off together.
So instead of flaking off inconspicuously, they all clump up and peel off together.

Now, your body actually has enzymes that repair a lot of the DNA damage caused by UV rays.
Now, your body actually has enzymes that repair a lot of the DNA damage caused by UV rays.

But, it can’t always repair all of it.
But, it can’t always repair all of it.

And if the damage isn’t fixed in one of your stem cells, you might have a real problem.
And if the damage isn’t fixed in one of your stem cells, you might have a real problem.

When those cells replicate, they might create a mutation at the site of the damage.
When those cells replicate, they might create a mutation at the site of the damage.

And depending on where the mutation occurs, this could lead the cell to become cancerous
And depending on where the mutation occurs, this could lead the cell to become cancerous

sometime down the road.
sometime down the road.

Remember, even if you don’t tend to burn, UV radiation can damage your DNA.
Remember, even if you don’t tend to burn, UV radiation can damage your DNA.

So if you know you’re going to be out in the sun for a while, make sure you’re covered
So if you know you’re going to be out in the sun for a while, make sure you’re covered

up or wearing sunscreen.
up or wearing sunscreen.

For me, being outside and exploring the world is super important for my happiness, and excites
For me, being outside and exploring the world is super important for my happiness, and excites

my curiosity.
my curiosity.

But it’s way more fun to go on an outdoor adventure without coming home to disgusting
But it’s way more fun to go on an outdoor adventure without coming home to disgusting

peeling skin.
peeling skin.

Ew.
Ew.