Do you need an excuse to get another tattoo? Then add this to the list: There is new scientific evidence that tattoos can toughen up the immune system.

University of Alabama researchers studied a group of people, collecting saliva before and after they got tattoos. They tested the samples for cortisol, a stress hormone known to suppress immune response, and immunoglobulin A, the antibody that fights off the flu and other infections.

The study, published in the American Journal of Human Biology, found that people with multiple tattoos had developed a higher pain tolerance and didn’t react as strongly to physical stress that comes with getting a tattoo. Those getting tattooed for the first time experienced much higher levels of immunoglobulin A, meaning they had higher stress response to getting a tattoo than those who had done it before. While researchers noted the small study size, they also said it shows how the body can be conditioned to respond to stresses over time.

But don’t resort to tattoos to harden your immune system. There are less painful ways to accomplish that. Get enough sleep and exercise regularly. Cut back on sugar, which can compromise cells that attack bacteria. Fresh fruits and vegetables can ward off illness.

Foster your relationships, too. One study found that lonely college freshmen had a reduced immune response to the flu vaccine compared with their more sociable peers. Get ahead of stress with meditation, working out and connecting with other people. If your happiness plan happens to include getting a tattoo, so be it. Just don’t run to the tattoo parlor whenever you need an immune system boost.