If you’ve always wanted a tattoo but never quite got around to it, now you have the perfect excuse: a study conducted by researchers from the University of Alabama, getting multiple tattoos can actually strengthen your immune system.

The first tattoo makes your immune system weaker, but the next ones help you get stronger.

Getting a simple tattoo lowers your immune system, at least temporarily. You’re injecting a foreign substance inside your body, and your organism gets a big confused and tries to fight it. But if you get more tattoos, it’s a bit like going to the gym. The first time is awful, and you’ll feel like crap. It’s not uncommon to feel quite drained after getting a tattoo. Dr. Christopher Lynn, UA associate professor of anthropology said:

“They don’t just hurt while you get the tattoo, but they can exhaust you,” Lynn said. “It’s easier to get sick. You can catch a cold because your defenses are lowered from the stress of getting a tattoo.”

But just like going to the gym, the more you do it, the better it gets. Therefore, getting more tattoos will train your body’s immune system.

“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.” In other words, you’re getting stronger.

This was the theory, and Lynn rallied former UA graduate student Johnna Dominguez,  and Dr. Jason DeCaro, UA associate professor of anthropology to test it.

Approaching volunteers at tattoo businesses in Tuscaloosa and Leeds, Dominguez surveyed them, gathering information on how many tattoos they got and the timeframe in which they got them. Then, they gathered saliva samples before and after. The researchers analyzed the samples, measuring levels of immunoglobulin A, an antibody that plays a critical role in the immune function of  mucous membranes. Immunoglobulin A also regulates portions of our gastrointestinal and respiratory systems, and cortisol, a stress hormone known to suppress immune response.

“Immunoglobulin A is a front line of defense against some of the common infections we encounter, like colds,” Lynn said.

They found that levels of immunoglobulin A dropped significantly for people getting their first tattoo. But the immunoglobulin A decrease was less so among those receiving tattoos more frequently, Lynn said.

“People with more tattoo experience have a statistically smaller decrease in immunoglobulin A from before to after,” said Lynn. In a way, getting a tattoo is like taking your immune system to the gym.

You can read the team’s full report in the American Journal of Human Biology.