You may be under the impression that you should get the COVID vaccine in your non-dominant arm because you’ll be using it less. But according to some experts, this is not the best course of action. In fact, Gail Trauco, RN, a registered oncology nurse and founder of Medical Bill 911, says your dominant arm may be the way to go. “Some experts recommend getting the vaccine in the dominant arm because of increased movement and increased blood flow,” she explains. Niket Sonpal, MD, an internist and gastroenterologist from NYC, adds that “getting the vaccine in your dominant arm helps your body absorb the vaccine fluid better.” And for more vaccine prep, Don’t Do This the Night Before Your Vaccine Appointment, Experts Say. According to the Centers for Disease Control and Prevention (CDC), one of the most common side effects of the COVID vaccine is arm pain and soreness. But increased movement could help reduce this soreness or ease it sooner—which is another reason you may want to consider your dominant arm for your shot.ae0fcc31ae342fd3a1346ebb1f342fcb As Peter Chin-Hong, MD, an infectious disease specialist and professor of medicine, told the San Francisco Chronicle, the vaccine causes pain in your arm because it is injected into your arm muscle and not the bloodstream, which causes your immune system to target inflammation at your muscle area. But as Trauco explains further, more movement helps move the vaccine away from the muscle injection site and into the rest of your body—meaning your immune system will start to target other areas. All of this may reduce soreness, she says. And for more on vaccine reactions, Be Prepared for This the Night You Get Your COVID Vaccine, Doctors Warn. If you’re not looking to reduce soreness or soreness time, you can still get the vaccine in your non-dominant arm, of course. In fact, some experts say there are a few reasons why you may want to choose this arm.  Leann Poston, MD, a licensed physician and medical expert for Invigor Medical, recommends that if you are a side-sleeper, you get the vaccine in the arm that you don’t sleep on so “you do not put pressure on it while sleeping.” If you sleep on your dominant arm, you might want to choose your non-dominant arm for the shot. Sonpal says you may also want to choose your non-dominant arm if you have to perform certain day-to-day actives, like writing or lifting heavy objects. However, Trauco warns that if you do choose not to get vaccinated in your dominant arm, this means “the vaccine remains at the injection site longer, which increases soreness.” And for more useful information delivered straight to your inbox, sign up for our daily newsletter. Regardless of which arm you choose, there are ways you can try to reduce any arm pain or soreness. The CDC recommends applying a “clean, cool, wet washcloth over the area” where you got the shot and using or exercising your arm. In terms of exercise, William Li, MD, a physician and president of The Angiogenesis Foundation, suggests swinging your arm around for a bit, flexing your arm to make a muscle, and pumping your fist for a minute or so. And for more on minimizing arm soreness, Do This Immediately After Getting Your Vaccine, Doctors Say.