Can A Sunburn Damage Your DNA? Here Are The Facts

When you spend too much time in the sun and get a sunburn, you’ll experience red, painful skin that can peel for the next few days.

But is it actually that bad for you? It usually heals in just a few days, and it’ll probably leave your skin looking a little bit more tan afterward—so what’s the big deal?

Sunburns are not just a temporary annoyance or inconvenience. They can have some serious long-term effects on your health.

How The Sun’s Ultraviolet Rays Damage Your DNA

Your DNA is made up of two long strands of molecules called nucleotides—adenine, thymine, cytosine, and guanine. These strands are twisted around each other to form a double helix.

When ultraviolet (UV) rays from the sun hit your skin, the highly energized photons can cause thymine nucleotides to fuse together. If you imagine the double helix of DNA as a ladder, the UV rays have caused some parts of one side of the ladder rungs to “melt,” causing a crooked kink that makes the ladder unstable.

This is called thymine dimerization, one of the main ways UV rays from the sun can damage your DNA.

Your body is able to repair some of this damage using a process called nucleotide excision repair, but it’s not perfect. If the damage is too severe, the cells containing the damaged DNA will die. And if the cell doesn’t die, the damaged DNA leads to malfunctions and mutations that can eventually develop into skin cancer.

Why Sunburns Turn Your Skin Red

When you spend too much time in the sun—if you are not wearing sunscreen—more and more of your skin cells absorb UV radiation and sustain damage.

This triggers an inflammatory response from your immune system to try to heal the damaged tissue. Your blood vessels will dilate to bring more blood to the area, and your skin will become red and swollen.

This is why sunburns are so painful. The damaged tissue is inflamed, and the extra blood flowing to the area makes it feel hot.

The inflammatory response also triggers your body to release histamine, leading to itching.

What About Tanning?

The new skin cells that are generated to replace the damaged ones tend to be made with more melanin in an attempt to shield the DNA from further damage. This increased melanin production is what gives you a “tan” after you’ve had a sunburn, but it’s not sufficient protection against UV radiation.

Although many people think of a “base tan” as a way to protect them from future sunburns, tanning does very little to protect your skin. A tan only seems to provide the same protection as SPF 2 sunscreen. General recommendations are that you should use an SPF of 30 or higher, so you still should use sunscreen even if you have a tan or have darker skin.

Also, remember that tanning (even without burning) is still the result of cell damage. So even though you may like how it looks, it also increases your risk of developing skin cancer. The Skin Cancer Foundation reports that even a single session of indoor tanning can increase your risk of developing life-threatening melanoma by as much as 75 percent. That tanned “healthy glow” is not so healthy at all.