system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If cells in your body do not live forever and tattoo ink is applied to skin cells, how are tattoos permanent?
gpt
Tattoo ink is embedded in the deeper layers of skin, called the dermis. During this process the dermis is damaged, and as it heals, it forms fibrous tissue - the equivalent of scar tissue. The ink gets locked into it, and stays there.

Scars do break down slowly over time, but the rate of cell replacement is hugely reduced. Regardless, tattoos will fade over time as the ink partially disperses, and the tattoo starts to get blurry. Sun damage also plays a part, but that's not related to this discussion.