When you get a tattoo, the ink is inserted via needle into the dermis, which is the second layer of skin. The body sees this ink as a foreign invader and activates the immune system to seek out and destroy the unfamiliar material. As part of this process, special white blood cells called macrophages envelop the ink and try to break it down with enzymes to a size small enough to be disposed of through the body’s lymphatic system. Here are some of the effects of tattoos on the immune system:

• Innate immune response: Getting a new tattoo triggers the immune system to send white blood cells called macrophages to eat invaders and protect against infection.

• Strengthened immune system: Individuals who frequently get tattoos appear to have higher levels of certain immune molecules, including antibodies, in their blood than people who rarely get inked. This effect seems to be dependent on receiving multiple tattoos, not just time passed since receiving one.

• Possible immune boost: Learning to coexist with tattoo ink could help immune cells calibrate their reactions to other substances, perhaps even heading off autoimmune attacks.

It is not clear if getting a tattoo is safe for immunosuppressed people, as there have been instances of severe muscle pain and swelling after receiving a tattoo. However, more research is needed to determine if this is caused by the tattoo process or by something else coinciding with getting the tattoo. While some scientists are studying the potential that tattoos could positively stimulate the immune system, more antibodies dont always translate into better immunity, and no one knows how long the effects really last.