Why Are My Muscles Cramping After My COVID Vaccine?

Why immunity can feel like you just did a boot camp.

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You were prepared to not be able to lift your arm up for a couple of days after your shot, but your body literally wasn’t ready for all-around soreness. The good news is, treating muscle cramps after getting your COVID vaccine is pretty simple, as long as you’ve got some hydration and painkillers on standby.

“The muscle cramps threw me for a loop,” says Arti, 29, who recently got the Moderna vaccine. “I was ready for my arm to fall off, but not to feel like I got kicked all over my body. It wasn’t mega intense, but it was everywhere for a day or two.” They took Tylenol and lounged on the couch playing video games for that first day and a half, which they say helped ease the aches — and kept their spirits up.

Why You Might Get Muscle Cramps After The COVID Vaccine

Many people who get the COVID vaccine experience injection-site pain — AKA, the arm you got your shot in might experience a bout of soreness to end all soreness. According to the Centers for Disease Control and Prevention (CDC), muscle pain throughout your body is also a common side effect, along with tiredness, headaches, fever, and nausea. (Put those all together, and you may feel like you’ve got the flu, which is normal.)

Why is your body freaking out and cramping your muscles along with your style? It’s largely about not getting enough H2O, says Dr. Michael Green, M.D., a family medicine physician and the associate medical director of Northwell Health-GoHealth Urgent Care. “Dehydration is a common cause of muscle cramps,” he tells Bustle. “Remember that your body is having an intense immune response to the vaccine and will use a lot of water for this.” Not to mention, you might be drinking fewer fluids if you’re also nauseous, but it’s important to try and down extra water before and after the appointment if you can.

When Should You Be Concerned About Post-Vaccine Muscle Cramps?

Your soreness may start relatively quickly, or it might creep up on you. “Muscle fatigue and aches can be experienced within a few hours of getting the vaccine,” Dr. Green says. “Muscle cramps can occur later as well,” so you don’t have to be overly concerned if you wake up sore the next day.

Muscle cramps after your shot aren’t necessarily a cause for alarm, says Dr. Natasha Bhuyan, M.D., the regional medical director of One Medical, but they are generally short-lived. Your post-vaccine aches shouldn’t last longer than a couple of days. “If body aches or muscle cramping doesn’t resolve within 48 hours, please reach out to your primary care provider,” Dr. Bhuyan advises.

Post-vaccine body aches usually aren’t super severe — you might feel like you just got out of an intense fitness boot camp — but Dr. Bhuyan says your level of full-body muscle pain shouldn’t really be interfering with your typical activities. If it is, a quick check-in with your doctor might be helpful to give you peace of mind.

How Do You Treat Post-Vaccine Muscle Cramps?

If your muscles are bugging you after your COVID vaccine, you don’t have to just wait it out. “Stretching and hydration can help,” Dr. Bhuyan says. When you’re dehydrated, your body has a harder time flushing toxins and regulating temperature, which can contribute to soreness. Let your body rest, and take an Epsom salt bath to relax your muscles if you’re got a bathtub and enjoy a good soak.

As with treating other post-vaccine side effects (think: fever and injection-site soreness), Dr. Bhuyan tells Bustle that it’s OK to take painkillers after getting your shot. Whether your medicine cabinet is stocked with ibuprofen or acetaminophen, neither med will negatively impact the vaccine’s effectiveness after you’ve gotten the poke.

“For me, I went to sleep that night and the aching was gone when I woke up,” Dr. Bhuyan says of her own vaccination aches. So no need to panic if your muscles are crampy post-vaccine — it’ll pass within a couple of days, and then you can celebrate your vaccination status.


Dr. Michael Green, M.D., family medicine physician, associate medical director of Northwell Health-GoHealth Urgent Care

Dr. Natasha Bhuyan, M.D., regional medical director of One Medical