everyday science

wear sunscreen

Let me ask you something:
What do you think/say when you see a tanned girl or a man?

  • Mmmm, nice
  • Hm, damn healthy
  • Yup, I am a freaking vampire
  • No sunscreen, ha
  • hmph, peasants!

Ah, most of the Earthlings are not immune to getting a nice brownish look while on a vacation. That’s just how we’ve been thought to act on a beach:
Be a freaking barbeque on the sand. It is *healthy* for you, they say. And then you turn crimson red and burn like a bloody lobster.

Myth debunk time:

Every form of acquired suntan is a huge cry for help from your skin. Every. Suntan. Even that “tan base”.

Actually, when the tan is created, the damage to your skin has already been done.
(Read that one more time)

I can easily say, tanning is a controversial machine. A little sun is good for you (like a source of vitamin D), while at the same time, you should stay far away in the shade to avoid skin cancer, premature aging, etc.

But how many of you really know what’s going on in your skin while building that sun’s given tan? 

Well, the short answer is that tanning is the body’s:

– defense mechanism signaling that harm is being done to our skin cells- way of trying to protect ourselves from further degeneration with melanin boost.

However, since we are all vanity-driven humans and enjoy a moment in the sun from time to time, perhaps tan deserves more than a sentence to explain.

Let’s get into the science of it.


While you are having a relaxing by the pool or at the beach, you probably don’t feel like you’re being bombarded by radiation. Oh well, that’s exactly what sunlight is. Pure radiation.

In addition to visible light and heat, there are three types of ultraviolet radiation from sunlight: UVA, UVB, and UVC.

We can basically ignore UVC radiation, as it never reaches the surface of the planet (or our skin) and is largely absorbed by the atmosphere.
However, UVA and UVB radiation do reach our sun-exposed skin and have various effects.

UVA radiation is much more common and isn’t filtered out by our planet’s ozone layer.

We are exposed to UVA rays throughout our lives, as they can even penetrate clouds and atmospheric gases. When UVA radiation strikes our skin, it immediately engages the melanocytes (the pigment cells in our skin), causing a release of the melanin they have already stored, resulting in what we know of as tan. 

UVA radiation penetrates deeper into the skin and can damage skin cells in the epidermis, leading to various types of skin cancer.

UVB radiation is slightly different, however, and only penetrates the top few layers of the skin, and is primarily responsible for sunburns, rather than suntans.

This makes UVB less of a danger for deep-layer skin cancers, but it can contribute to melanoma and those uncomfortable sunburns.

Reality check

Radiation of any kind penetrating the skin can damage DNA in those affected cells, which is why humans have adapted melanin – to repair and protect the body from that damage.

When UVA radiation penetrates the skin, it causes the existing melanin to darken but does not stimulate the production of more melanin.
The color change resulting from UVA radiation is due to oxidative stress on the melanin, which changes its color. However, this is not a long-lasting color change, and the tan from UVA rays will usually fade in a few days.

UVB radiation is the key component in the second stage of the tanning process. The damage caused by UVB rays stimulates melanogenesis, the body’s natural response to radiation (producing more melanin). This type of tan will be much longer-lasting and it actually protects your skin from further radiation damage, as the melanin produced will absorb that radiation.

UVB radiation can typically be blocked by sunscreen, whereas UVA rays are more difficult to protect against; fortunately, natural and synthetic fibers (clothing) have been shown to protect against the majority of UVA rays.

The melanin produced and released by melanocytes comes in two pigment forms: eumelanin (brown) and phaeomelanin (yellow and red).

Depending on a combination of your hair color, skin tone, race, genetics, and previous exposure to sunlight, the production levels of these two pigments may be different.

What is a Tan?

Melanocytes are special skin cells that produce melanin (skin pigment) when they are exposed to ultraviolet light in sunlight.

The pigment absorbs UV radiation in sunlight, so it helps to protect skin cells from UV damage.

Your body actually produces two kinds of pigment.

One is called eumelanin and it is responsible for the golden brown color we normally associate with tanning. Another pigment is called phaeomelanin and it produces a red color.

For example, a fair-skinned, red-headed Irishman produces more phaeomelanin and less eumelanin, which is why he basically doesn’t tan at all.

So, the infamous tanning is a protective measure that the human body takes when it senses danger from UV rays. When you expose your skin to UV radiation from the Sun, melanin is transferred from melanocytes (cells that make melanin) to keratinocytes (another type of skin cell). And ta-da, this is what causes your skin to tan.

Hm, but How Does Your Body Know It’s Sunny Out?

Sunlight (or UV light from tanning beds) affects the pituitary gland (a gland at the base of the brain that secretes hormones) which then produces MSH (melanocyte-stimulating hormone).

This hormone flows through the bloodstream to the melanocytes, which makes them able to produce more melanin.

Weird fun fact: Since the pituitary gland is tied into the optic nerve, (the nerve in your eyes that lets you sense light), wearing sunglasses makes you tan less (because of reduced melanin production). What a hack.

Wear Sunscreen.

If I could offer you only one tip for the future,

Sunscreen would be it.

Leave a reply

Next Article:

0 %