APR 16, 2016 6:49 AM PDT

Forever Body Art: The Science Behind Tattoo

WRITTEN BY: Xuan Pham

Humans have been decorating their bodies with tattoos and piercings since at least the Neolithic era thousands of years ago. While modern technologies have expanded the range of available dyes, today's technique of tattooing remains arguably similar to the technique used long ago. That is, needles insert ink deep into the dermis layer of the skin so that it becomes permanent. But skin cells shed every two to three weeks, so why doesn't the ink get sloughed off along with the cells?

The answer has a lot to do with the immune system. In fact, tattoos can be thought of as an inflammatory process. Each time a needle punctures the dermis and delivers an ink load, the body sends macrophages to the wound site to "eat" the foreign pigment particles in an attempt to clean the wound. But the dermis layer ends up trapping the stained macrophages, giving the desired permanence effect.

While permanent, the ink can fade, blur, and even migrate with aging. And reversing a tattoo's effects is similarly painful as getting it in the first place. To erase a tattoo, lasers are used to break up the pigment particles until it's small enough to be cleared out by the immune cells. This process is lengthy as it is painful and could cause scarring, which could be considered another form of a permanent tattoo.
About the Author
  • I am a human geneticist, passionate about telling stories to make science more engaging and approachable. Find more of my writing at the Hopkins BioMedical Odyssey blog and at TheGeneTwist.com.
You May Also Like
APR 19, 2020
Space & Astronomy
Expedition 62 Returns Home From the International Space Station
APR 19, 2020
Expedition 62 Returns Home From the International Space Station
After spending several months onboard the International Space Station conducting science experiments and risky spacewalk ...
APR 27, 2020
Space & Astronomy
Hubble Snaps Gorgeous Photo for 30th Anniversary
APR 27, 2020
Hubble Snaps Gorgeous Photo for 30th Anniversary
The Hubble Space Telescope surpassed its 30th year in space on Friday, April 24th. Being that it’s one of the most ...
MAY 25, 2020
Plants & Animals
Cuttlefish Are Amazing, and Here's Why
MAY 25, 2020
Cuttlefish Are Amazing, and Here's Why
Many people have heard of the cuttlefish but haven’t actually seen one in person – and we’re just goin ...
MAY 31, 2020
Space & Astronomy
Another SpaceX Starship Prototype Explodes During Testing
MAY 31, 2020
Another SpaceX Starship Prototype Explodes During Testing
Incomplete Starship prototypes are a common sight if you follow SpaceX’s plethora of rocket-centric projects, but ...
JUN 26, 2020
Space & Astronomy
Astrophysicists Find Evidence of Nearby Planet that May Sustain Life
JUN 26, 2020
Astrophysicists Find Evidence of Nearby Planet that May Sustain Life
Researchers have found that a nearby red dwarf star, known as Gliese 887, may host three planets, one of which could sus ...
JUL 07, 2020
Neuroscience
How Blindsight Helps Us Explain Consciousness
JUL 07, 2020
How Blindsight Helps Us Explain Consciousness
Blindsight is the phenomenon in which blind people can interact with their environments even though they can't see i ...
Loading Comments...