Most people who have tattoos find them to be oddly similar to eating potato chips: one just isn't enough. After getting your initial ink [1], you likely became addicted to the adrenaline rush [2]. You know that every time you visit your favorite parlor, it's far from being your last appointment. Maybe your arms are covered with colorful sleeves, or perhaps you've decorated your body with countless tiny tats [3]. Regardless of how you decorate your skin, your addiction is bad news for your wallet — but it may actually be good for your health.

Recent research published in the American Journal of Human Biology [4] shows that getting inked stimulates the immune system. The 29 participants in the study provided saliva samples before and after getting a new tattoo, and the researchers analyzed the levels of immunoglobulin A (an antibody found in mucous membranes) in each sample.

According to The Huffington Post [5], the level of immunoglobulin A in the candidates who were receiving their first ink dropped much lower than those who had multiple tats. This implies that the immune system of those with more "tattoo experience" is adjusted to the ink process and trained to react faster to stressors.

Christopher Lynn, an associate professor of anthropology at the University of Alabama and coauthor of the study, told The Huffington Post that the body's response is similar to someone out of shape hitting the gym. You're immediately sore (even for days!), but with consistent workouts, your body adjusts.

"After the stress response, your body returns to an equilibrium," Lynn said. "However, if you continue to stress your body over and over again, instead of returning to the same set point, it adjusts its internal set points and moves higher."

You don't want to use these findings as an argument for getting your first tattoo — in fact, that first ink can make you more susceptible to illness, as your body is stressed by that experience. But, if you're already addicted, it's just another reason to love your body art even more.