The Secret to a Tattoo's Permanence: The Immune System

The dye gets lodged deep in the skin thanks to hungry anti-inflammatory cells called macrophages.
More

We rarely stop and think about the science of tattoos. In fact, some people don't even stop and think before getting tattooed.

We kind of know the reason they last forever ... because the ink goes so deep into your skin that it can never wash off ... or something? 

It's not that simple. As this fascinating video from TED explains, tattoos are actually a complicated inflammatory process—a delicate balancing act between your body and the dye that's invading it.

It turns out your ethereal watercolored bird is kind of like an infection—and the reason it's permanent is because your body keeps on fighting it forever.

Tattoo needles punch through the epidermis, the outer layer of skin, and drive the ink into the dermis, the deeper layer that's mottled with nerves and blood vessels.

"Every time the needle penetrates, it causes a wound that alerts the body to begin the inflammatory process," the video explains. That signal sends immune system cells racing to the site of the wound (or multiple wounds, in the case of the five-inch dragon breathing fire across your chest).

Special cells called macrophages come to the rescue, eating up the dye in an attempt to "clean up" the inflammation it's causing. The rest of the dye gets soaked up by skin cells called fibroblasts. The fibroblasts, along with many of the macrophages, stay suspended in the dermis in perpetuity.

The dye in the bellies of the trapped macrophages and fibroblasts shows through the skin, projecting your Chinese word for "love" or constellation of tiny blue stars to the outside world.

And in case you accidentally got "Only God can fudge me" written on the nape of your neck, the video also explains how you can, um, get that fixed. No fudgment.

Jump to comments
Presented by

Olga Khazan is a staff writer at The Atlantic, where she covers health.

Get Today's Top Stories in Your Inbox (preview)

CrossFit Versus Yoga: Choose a Side

How a workout becomes a social identity


Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register. blog comments powered by Disqus

Video

CrossFit Versus Yoga: Choose a Side

How a workout becomes a social identity

Video

Is Technology Making Us Better Storytellers?

The minds behind House of Cards and The Moth weigh in.

Video

A Short Film That Skewers Hollywood

A studio executive concocts an animated blockbuster. Who cares about the story?

Video

In Online Dating, Everyone's a Little Bit Racist

The co-founder of OKCupid shares findings from his analysis of millions of users' data.

Video

What Is a Sandwich?

We're overthinking sandwiches, so you don't have to.

Video

Let's Talk About Not Smoking

Why does smoking maintain its allure? James Hamblin seeks the wisdom of a cool person.

Writers

Up
Down

More in Health

Just In