Pro soccer players' viral reactions make it seem like the anti-cramp supplement HotShot is unbearable. That's exactly why it works, says trainer.

• NWSL players have gone viral for their over-the-top reactions to HotShot, a spicy sports drink.
• The beverage was specially designed by a Nobel prize-winning neuroscientist to stop muscle cramps.

Some of the world's foremost professional soccer players are throwing back spicy shots mid-game to help stop cramps in their tracks.

Several NWSL stars have gone viral for their flamboyant on-field reactions — including choking, gagging, and flailing — to the 50-milliliter shot of liquid heat aptly dubbed "HotShot."

"I mean, it's funky for sure, but it works," Wafaa Chatila, the head athletic trainer of the NWSL's Kansas City Current, told Insider.

Both Chatila and Pratik Patel, the team's nutritionist, often turn to HotShot to help athletes stop cramps in their tracks. The drink's formula — developed by Nobel Prize-winning neuroscientist Rod MacKinnon and Bruce Bean, a neurobiology professor at Harvard Medical School — is specially designed to rapidly return an impacted muscle to its standard state so that cramps don't curtail an athlete's performance.

MacKinnon and Bean identified what causes cramps, then developed a solution that works rapidly

To understand how HotShot works, it's important to understand the mechanics of cramps. One prevailing hypothesis of what causes exercise-associated muscle cramps (EAMCs) — the neuromuscular theory, per the NIH — suggests that the more a muscle fatigues, the less equipped it is to handle the influx of motor neurons signaling to contract and release.

Evenutally, the impacted muscle seizes up and creates a cramp, which can be an excruciatingly painful experience that sometimes limits one's mobility almost as soon as it begins.

MacKinnon and Bean have experienced this intense pain first-hand. The pair were kayaking in the ocean off the coast of Cape Cod one fall when they "simultaneously suffered muscle cramping in our arms" and subsequently struggled to steady their boats, Bean said on the BioHackers Lab Podcast.

They almost immediately set out to develop a solution, applying their knowledge from years of neuroscience research. MacKinnon and Bean identified special receptors in the mouth, throat, and stomach — transient receptor potential (TRP) ion channels — that "send an inhibitory signal through the spinal cord to stop that hyperactivity" of the motor neurons, HotShot president and CEO Matthew Wohl told Insider.

HotShot's main ingredients — capsaicin, a red pepper extract; ginger, an acetic acid; and cinnamon, a heat generator — offer the perfect cocktail of heat and acetic acid necessary to kickstart those receptors. But the taste, Wohl admits, is "intense."

But that instensity has a purpose. "It's not just for the hell of it," Wohl said.

"It had to be intense to drive the neurological effect," Wohl said. "That's why it works so fast, because you're just stimulating those activators in your mouth, throat, and stomach. You don't have to digest it, and it doesn't have to be absorbed into your bloodstream or into your body."

The 'intense' taste has created some questionable press for HotShot

During a June match against the Orlando Pride, Kansas City rookie Michelle Cooper went viral for her near-hysterical reaction after Chatila gave her a HotShot. In a clip from the game, she chugs the liquid, then immediately grimaces and waves her hand in the air. Cooper even sticks her tongue out and coughs before shooting water into her mouth.

"NEVER again," Cooper wrote on Twitter after the game:

Still, Chatila had no regrets about giving it to her. She stands by HotShot, which she's seen "work in like a minute or so."

Not only is that considerably faster than the typical several-minute recovery period for a cramp, but it also cuts out the longer waiting period often necessary to avoid the onset of another cramp due to a "post-exercise period of increased susceptibility," per a 2017 Sports Medicine study.

"By the time you give it to them and you stretch them out, they get a little bit of water, and then you get them up walking, usually it's done," she added.

Days after Cooper's incident, Angel City FC striker Alyssa Thompson had a similar response to taking a HotShot. After the game, the 18-year-old said "it was really gross and I did not like it at all."

And when asked at the US Women's National Team's media day whether she was in talks with the brand for a sponsorship, she quickly replied "I hope not!" But in the moment when a cramp strikes, as Chatila noted, athletes are often singularly focused on alleviating their discomfort.

"When an athlete gets a cramp, depending on where it is, it can be incredibly painful," Patel added. "So the trade-off of having to drink something isn't the best tasting in the world to get that cramp to chill out, I mean, it's worth it."

Somehow, despite their negative sentiment, the viral reactions have been a boon to HotShot's business

Whether due to curiosity or masochism, NWSL fans and media members have flocked to the company's website and purchased HotShots to try for themselves after watching Cooper and Thompson choke down the product.

"We started getting a lot of hits to our Instagram, traffic to our website spiked significantly, and orders started spiking," Wohl said of the days following the viral videos.

There's now even a HotShot Challenge circulating the web. The company has partnered with Portland Thorns and Canada Women's National Team star Janine Beckie to help encourage everyone to try HotShot.

For every video fans post of themselves sipping the spicy beverage, HotShot has pledged to donate $2 to the Women's Sports Foundation.