Ink particles are too big for your white blood cells to gobble up, which is why they stick around in your skin. During a tattoo removal, the laser blasts the top layer of ink into smaller pieces, making them bite-sized for your immune system. After a laser treatment, it’s your own body that actually erases the tattoo.

It takes time for all of the particles to be flushed (literally! They come out in your pee) from your system – at least three months – and the efficiency of the process all comes down to your own immune system. That’s why it’s so important to take good care of yourself while removing a tattoo: get good sleep, drink enough water, and try not to burn yourself out.