Scientists now know why tattoos last a lifetime

Scientists at the Immunology Centre of Marseille-Luminy in France have discovered that the immune cells, called macrophages, that eat the ink injected into your skin recycle the pigments to new cells when they die, reports Nature. When macrophages die, they release the pigment, which is then ingested by neighboring macrophages. The scientists carried out the tests that led to the discovery of macrophagic recycling in mice, but since they are so genetically similar to humans, it’s likely the same process takes place in human macrophages, which explains why you’re going to be stuck with that “mom” tattoo for life.