Doctor Explains How Sunscreen Affects Your Body

Summer is officially here.

The sun is out, it is shining and,

sorry to be a downer, but so are it's cancer causing rays.

Everybody knows protecting their skin from the sun

is important and most of us have heard our whole lives

that sunscreen is the best defense for that.

But a new study, backed by the Food & Drug Administration

has shown that some chemicals in some sunscreens

can actually penetrate the skin and wind up

in your blood stream.

So what does that mean for you and protecting

your skin this summer?

To find out we're talking with Kanade Shinkai,

she's a Dermatologist at UC San Francisco

and Editor in Chief of JAMA Dermatology.

So, I think this study raises a lot of questions

for people on whether they should continue

to wear sunscreen.

So just top line question;

is wearing sunscreen still a good idea?

Wearing sunscreen is still a good idea.

And sunscreen, though, is just one part of

protecting your skin from the sun

and that includes seeking shade,

trying not to do physical activities

or activities outdoors during the peak hours of the sun,

which are between 10 and two pm and then using

other protective mechanisms like using hats,

sunglasses, protective clothing,

so sunscreen's just one part of protecting

your skin from the sun.

Can you tell us a little bit about what the study

looked at and what it found?

Yeah, so the study's a small pilot study

that looked at the application of four different

commercially available formulations of sunscreen,

these are things that are available at most drug stores.

They measured the absorption of the key sunscreen

ingredients in the blood over time and also

after the application had stopped and what it found

was that there is notable absorption of the

sunscreen ingredients into your bloodstream

and that they reached levels,

really just after a few hours of applying the

sunscreen and will stay elevated for almost

a day or two after you stop using the sunscreen.

So this means that when we put sunscreen on our skin,

it's getting absorbed through the skin and it's

going into our bloodstream and it hangs around

for a lot longer than the application and the levels

that were found in the study were greater than

the levels that the Food & Drug Administration here

in the United States uses kind of as a threshold

to do safety testing.

But the safety testing has not been done,

so really, what it's telling us is that sunscreen

gets absorbed into the bloodstream,

it reaches levels that are higher than this

regulatory threshold and the safety testing

has not been done yet.

I think, when a lot of people first read about this study,

they read oh, there's chemicals in sunscreen,

it's getting into my bloodstream.

Chemical has become kind of an unhelpfully broad,

kinda scary term for a lotta people.

They'll hear it and think oh, chemical is bad and unsafe

and dangerous, but the fact is all physical matter

is chemicals, right?

So it helps to talk with specifics here.

So what kinds of chemicals did this study find

in people's bloodstreams?

Yeah, well there's two different types of sunscreen.

One type we call mineral sunscreen and these are

literally minerals; zinc oxide and titanium dioxide,

they coat the skin.

Technically, you could call it sunblock.

They also often leave a very white color on the skin

so a lot of people don't like to use it for that reason.

Those have been tested and don't have any

systemic absorption so we know that those are safe.

The other type of sunscreen is what we

colloquially call chemical sunscreen.

So these are literally chemical filters

that absorb ultraviolet light and these are the ones

that are in question, these are the ones that have

never been tested in terms of their safety,

or their systemic absorption, four of which were the ones

that were studied in this particular research article.

What ingredients, in sunscreens specifically,

was this study looking at?

This particular study looked at

four sunscreen ingredients:

Avobenzone, Oxybenzone, Octocrylene and Ecamsule.

What do these chemicals actually do inside the body?

Is that something we know?

Yeah, so we don't really know.

There's never been any research article that has suggested

that these chemicals are doing anything harmful

to the human body.

There are some studies, however,

that have been done in lavatory animals and, of course,

take it with a grain of salt because these studies

always use doses that are a lot higher than what

a person would be exposed to,

but there have been some data points that have suggested

changes to your hormone levels,

changes in reproduction and those have at least

raised the question of whether or not safety testing

should happen in humans.

But that safety testing has not happened yet.

Even if we take the animal studies with a grain of salt,

I think that not knowing is still an unsettling

prospect for people.

So the question that I would imagine a lot of people

are asking is; should I still wear sunscreen?

Is it safer to be exposed to the sun unprotected,

or to use this product on my body that

has effects I may not fully understand?

Yeah, well there is something absolutely certain,

which is that the sun and sun exposure,

and especially prolonged sun exposure can result in sunburn,

which is unhealthy, and also can lead to skin cancer.

That is not in question in this study.

I think what's in question is really about

how effective sunscreen is in protecting long-term

from skin cancer and melanoma, as well as whether it's safe.

A lot of consumers don't know that sunscreen's

actually considered a medication and so because of that

usually all over the counter medications are

subjected to a battery of testing but that has

never been done for these chemical sunscreens

and that's why this study is so important.

Why hasn't that been done for sunscreen?

You know, sunscreens have been around for a long time

and they really preceded, kind of the standard way

that we evaluate over the counter medications

in this country and so usually in history and time

we find out that a medication has some side effect

that might be dangerous to people and it gets

taken off the market, now what we try to do

is do those safety studies in advance of the

medication coming out.

However, that hasn't been done for sunscreen

because, in large part, the sunscreens predated

that type of drug regulation.

Over time, and in fact as early as 1999,

the Food & Drug Administration asked sunscreen companies

to do these regulatory studies but for various reasons

they have not been able to see that data.

What are alternatives to sunscreen,

or sort of ways of supplementing the sun blocking

effects of sunscreen?

Right now, there are sunscreens that we know are safe

and these are the mineral sunscreens that we

talked about earlier and those are not in question at all

and those have been tested.

If people are choosing between chemical sunscreen

and mineral based sunscreen,

is there a cost difference?

There's no cost difference.

Are they as effective as one another?

Well, as far as we know they're as effective.

One of the things that we, as dermatologists,

are still trying to determine is what is the

effective dosage of sunscreen?

I think common sense would say you wanna put it on,

and we all know it rubs off when we go swimming,

or when we towel off or when we sweat.

It still needs to be determined whether or not

there's a particular dose of mineral or chemical sunscreen

that is ideal for the prevention of

skin cancer and melanoma.

I think one important piece of this study,

the research article that we're talking about,

is that this was idealized conditions.

So the subjects put the sunscreen on and they sat

in climate controlled environments,

so they weren't swimming, they weren't sweating

or even moving around and they weren't actually

exposed to the sun and so we don't know what,

in the real world and under real world conditions,

what those systemic absorptions are like,

whether they're the same or not to those found

in this particular study.

Speaking of real world conditions and the

question of dosage,

there's also this factor of behavioral psychology, right?

Which is, I know there have been some studies

that look at people who apply sunscreen and think

that they're getting the protection in some cases,

and in some cases get burned worse than people

who are taking protective measures to protect themselves

knowing that they haven't applied sunscreen.

So that's, the real world scenario is a really big variable

that is hard to account for.

It is and this has actually been shown in studies.

People put on about half the amount of sunscreen

as on a sunscreen label, so that's one important

real world condition as well but we don't actually know

whether those real world conditions,

for example, if you just use less sunscreen

to get less absorption, whether that would impact

its safety and effectiveness as a tool to prevent

skin cancer and melanoma.

What are the next steps for the

Food & Drug Administration?

So in February of this year there was a proposal

put forth that the Food & Drug Administration will

really mandate that sunscreen companies provide

the safety testing.

So the onus is really on the sunscreen companies,

not on the Food & Drug Administration.

What are the next steps for sunscreen manufacturers.

Yeah, so the sunscreen manufacturers are now

going to be required to test their products

for safety testing.

So that safety testing will begin with

systemic absorption, so looking to see if it gets

absorbed into the sunscreen,

and that's for 12 ingredients in this particular FD ruling,

and if there is evidence of systemic absorption

past the, or above, the safety threshold

that the Food & Drug Administration has for all,

it's common to all medications,

then it will trigger additional safety testing,

which included toxicity studies, cancer risk and

effects on things like hormones and reproduction.

How soon could this realistically affect what

people see on the shelves at their local

pharmacy or supermarket?

Well, in theory, if the sunscreen companies

don't provide this data by November of 2019,

in theory these products could be pulled from the market.

I think we would all agree this would be

a very extreme measure given that we don't actually have

any data right now that they're unsafe.

However, this is sort of what is being set up

by this current proposed ruling.

That being said, I think companies also need time

to do the studies and likely there will be an opportunity

for them to request extensions as long as they're

working on doing the testing that's been requested.

What is sort of the one big takeaway people should

have from this study?

It's really important for people to know that

it's really essential for them to protect their skin

from the sun and there's lots of different ways to do that.

And sunscreen is an important piece of that

so people should still wear sunscreen.

If they have concerns about the chemicals that

were in this particular study,

they can choose things that we know are safe,

including the mineral sunscreens that we

talked about earlier.

But the real key here is that we don't know,

especially from this study,

that the four sunscreen ingredients that were studied

are actually dangerous, we don't know that yet.

And we do know that sun exposure is dangerous.

We absolutely know that.

That is not in question.

Well, thank you very much for joining us today.

It sounds like sunscreen is still a good idea.

If you don't wanna use sunscreens that have these

sort of chemicals in them,

the effects of which are kind of unclear,

you have other options and people can, of course,

stay out of the sun and wear protective clothing too.

Absolutely.