system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do tattoos not wear off? Don't the skin cells at the tattoo get replaced by newer cells?
gpt
Tattoo ink becomes embedded in fibroblasts, cells that are very important in healing. Andi t just kinda stays there, the tissue they heal carrying the same color as the ink. It actually intentionally destroys a bunch of the epidermis tissue that was ther ebefore the injection.

Unfortunately this does tend to over time migrate deeper into your skin, resulting in the faded colors you see in older tattoos.