Robert Downey Jr. said that taking one before the Golden Globes would make the awards show “a breeze.” Khloe Kardashian has admitted to raiding her mom Kris Jenner’s supply of them to manage stress around the paparazzi. And Kristen Bell joked that they might not make one that can handle her needs.

It’s a beta blocker — specifically, propranolol — a blood pressure medication that has suddenly become a go-to pill for anxiety and stress. While SSRIs (short for selective serotonin reuptake inhibitors) are usually prescribed for those conditions, beta blockers also work by increasing the amount of serotonin in your brain. And people are into it.

But why?

“Propranolol crosses the blood brain barrier a little bit more than than other beta blockers, so it does actually have that effect on the anxiety,” Dr. Joseph Squitieri, division director for adult ambulatory psychiatry at Northwell Zucker Hillside Hospital, tells PEOPLE. “It works by decreasing the sympathetic nervous system response.”

Specifically, Dr. Squitieri tells PEOPLE “it blocks the beta receptors in the heart, and it slows the heart rate, reduces the force of heart contractions — which lowers blood pressure — and it inhibits the fight or flight response.”

Its popularity is likely due to a recent marketing campaign, says Dr. Squitiere. The celeb mentions don’t hurt, either.

“Propranolol will reduce the stress on the heart and the overall cardiovascular workload and response,” he says, adding that it suppresses symptoms that can be uncomfortable.

Those include racing heart, sweating, flushing of the skin, tingling or numbness in your hands, or as he explains, “think of all the symptoms that someone could experience with a panic attack.”

But while it may be helpful in “limited situations,” Dr. Squitieri tells PEOPLE, “it’s masking the anxiety because it’s pushing down those symptoms.”

Maybe “the fear of public speaking might be deeply rooted in childhood or maybe some trauma from the past,” he says, adding that those causes of anxiety “can be better addressed, usually, by therapy.”

There are also people who shouldn’t take beta blockers, he explains, like asthmatics, as it can “precipitate asthma attacks.” And, of course, he advises those with any “cardiac issues consult (to) your medical doctor before taking a beta blocker.”

While a beta blocker like propranolol may be helpful in “specific situations” like public speaking, Dr. Squitieri says it’s “probably not the best treatment for anxiety long-term or chronically.”

“If anxiety is really impacting your work or your home life,” he recommends “speaking to a professional about the best course of treatment would be.”

Never miss a story — sign up for PEOPLE’s free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from celebrity news to compelling human interest stories.