Medicine & Health
How does a tattoo work?
A tattoo works by using a needle to deposit ink into the second layer of skin (the dermis), below the surface that sheds. The ink is trapped there permanently — partly because your own immune cells hold onto it — so the design stays visible for life.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a tattoo works.
Step by step
- 1A needle punctures the skin rapidly, injecting ink into the dermis (the deeper layer).
- 2The outer layer (epidermis) constantly sheds, but the dermis does not — so the ink stays.
- 3The body treats the ink as a foreign invader; immune cells engulf but can't remove it.
- 4Those ink-filled cells stay in place, keeping the tattoo visible.
- 5Tattoos fade slowly over years as some ink disperses and the skin ages.
Frequently asked questions
- Why are tattoos permanent?
- The ink is placed in the dermis, a deep skin layer that doesn't shed. Immune cells engulf the ink particles but can't carry them away, so they stay put for life.
- Why do tattoos fade over time?
- Sunlight breaks down ink, and some particles slowly disperse or are carried off by the immune system, so colors soften and blur over many years.
- How does laser tattoo removal work?
- Lasers shatter the ink into fragments small enough for the immune system to carry away gradually, fading the tattoo over multiple sessions.