system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why don't tattoos disappear every 5 years seeing as every atom in your body is replaced?

Seeing as approximately every 5 years, every atom in your body is replaced, why don't tattoos disappear? Also knowing that skin regenerates and sheds over time.
gpt
Not all skin sheds and regenerates over time.

The ink from tattoos is deposited deeper than your outer layer of skin (the names for the layers escape me right now). Your outer layer of skin is constantly shedding and being replaced by cells replicating inside, but that second layer of skin (where the ink is) isn't replaced in the same fashion, so the ink isn't displaced.