Can HotShot’s Spicy Mouth Rinse Really Kill Your Cramps?

Bruce Bean, a neurobiologist at Harvard Medical School and his friend, neuroscientist Rod MacKinnon, spent a fair amount of time in the lab drinking vinegar and Tabasco. Also vinegar and mustard. In scientific terms, it was disgusting. But this is the bleeding edge of cramp research: stimulating nerves in the mouth to prevent or shorten a muscle cramp elsewhere in the body, effectively resetting the neuromuscular feedback loop.

The two professors were looking for a concoction spicy enough to light up the sensory neurons in the mouth, without being so revolting it would never get past the lips. They landed on HotShot, a lively cocktail of cinnamon, ginger, and capsaicin, the heatmaker in chili peppers.

According to Dr. Bean, while dehydration and electrolyte imbalance in the muscles have been fingered as contributors, the root cause of muscle cramps is not well understood. Yes, they know cramps are the result of overactive, repetitive neural messages to and from the cramping muscle, but why do these neurons freak out in the first place?

“The short answer is, we don’t know,” Bean says. He explains that muscles are governed by enormously complex feedback mechanisms of excitatory and inhibitory elements. When those elements are in balance, muscles contract and relax according to direction they receive from the brain. He and MacKinnon speculate that when a muscle is used frequently, and the excitatory factors are in heavy rotation, the inhibitory elements are weakened, and the fragile balance is thrown off—a state quite easily achieved. Epilepsy is an example of chronically over-active excitatory factors: A muscle cramp is a similar imbalance on a much smaller scale.

Bean and MacKinnon also don’t know exactly why stimulation of sensory neurons in the mouth, esophagus, and stomach calm hyperactive nerves elsewhere in the body. Their hypothesis is that stimulating these neurons releases neurotransmitters like dopamine, serotonin, and norepinephrine— chemicals with well-known muscle inhibitory elements. From there, it was a matter of trying to find natural spices that would most effectively stimulate neurons in the mouth and be somewhat palatable.

Of course, there was decades-old anecdotal precedent—cyclists used to drink pickle juice to relieve muscle cramps, but it was thought that the sodium and electrolytes in the juice relieved an imbalance in the muscles. In fact, it was the vinegar tickling neurons in the digestive tract that did the trick.

But while strong stimulation of the mouth might nudge neuromuscular performance back into balance, what happens when that spice bomb hits the swirling, churning tummy? Surprisingly little, Bean says. Capsaicin actually reduces stomach inflammation, and ginger is a well-known digestive aid. While HotShot is an acquired taste, they’ve had very few complaints of stomach upset.

Note to athletes who find this stuff unpalatable: Bean says swishing and spitting the shot may do the anti-cramp trick, no gulping necessary.

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