What’s the deal with spicy food? How is it hot — and yet also not? And how does it make masochists of so many otherwise non-masochistic people?

Spicy food brings an intimate pain that, for some, just hurts so good. The pain of spiciness, a.k.a. piquance, comes from the effects of a little molecule called capsaicin (pronounced “CAP-suh-sin”), found in chili peppers of the genus Capsicum. Capsaicin also explains why spicy foods make you poop, why spicy food is good for you (sometimes), and why spicy food is bad for you (othertimes).

Capsaicin is one of Mother Nature’s ‘less-lethal’ assaults, designed to protect plants from unwanted eaters. In this case, hot pepper plants native to the Americas evolved to attract birds while antagonizing mammals, whose stomachs are too damn acidic to make them useful propagators of viable pepper seeds. Unlike birds, mammals like us have certain heat/pain-sensing receptors, which capsaicin targets in a kind of psyops maneuver that tricks your brain into registering a heat threat.

Very clever. But what Capsicums didn’t anticipate is mammals with masochistic tendencies. People the world over don’t just eat spicy food, they love it, celebrate it, and compete with one another to breed and consume ever spicier peppers for the thrill of it. From their origins in Central and South America, chili peppers have been transformed into a massively successful global commodity used by cooks — and violence workers (for police- and military-grade pepper sprays) — the world over. The global trade in chili peppers amounts to nearly $30 billion, more than either coffee or tea.

It’s safe to say hot pepper plants have found a way to propagate; their means of repulsion has become a means of attraction. Whatever works!

Although some cultures have considered it so, ‘spicy’ is neither a taste nor flavor in the eyes of modern science. Technically it’s not even heat, but rather fake heat, just as mentholated items like mint are actually fake coolness. How does that work?

As you chow down, the spicy-spicy in your shrimp creole activates temperature-sensing receptors in and around the mouth with a misleading message: Fire in the hole! Fire in the hole! But it’s not real fire, so it’s technically safe (however unpleasant) to ignore the pain signals being sent to your brain. Spicy food doesn’t physically burn your mouth.

What’s actually happening is the capsaicin molecules plug in to heat/pain sensors on your nerve cells and then re-calibrate them, lowering the threshold at which heat is registered as pain. That is why spicy munchies feel hotter, in terms of temperature, than they literally are. At this point, your nervous system takes pity on you and sends in a cascade of mollifying endorphins to ease the pain. These endorphins, of course, are why some people get addicted to the five-alarm burn. But there are built-in brakes on any chili heat addiction.

Like real heat, the fake heat of chiliness generates pain, but in a way the pain, too, is fake. That is, if you can vasodilate your way into an extreme-pepper habit, after awhile you may find that the burn begins to subside. There is a numbing effect, and this reflects the transition from over-stimulation of your nerves to their more-or-less temporary paralysis.

Overwhelming spiciness can take out your heat sensors one by one, making it less painful to consume capsaicin over time. Basically, the more spicy food you eat, the more you can tolerate it due to a decrease in sensitivity to its effects. That’s why some people are able to consume copious amounts of fire while others are practically allergic to being in the same room with chilis. You can get to the point where an habañero doesn’t even taste grocery-store Mild.

This surprising analgesia was put to good medicinal use in the pre-Columbian past by indigenous Americans. The Aztec, for example, were known to treat certain kinds of oral inflammation with chile paste. By the nineteenth century, the Chinese were using imported chili extracts to numb eunuchs-to-be ahead of their castrations. Today, traditional healing practices in many cultures incorporate capsaicin-containing compounds to treat a variety of ailments involving pain and other issues.

However, before you rush to smear chile paste all over that rash on your bum, know that the medicinal use of chili heat is no undertaking for amateurs. In fact, it’s not so clear the experts have mastered the craft either. Let’s just say many, many lab rats have suffered for the sake of capsaicin-based curatives, and their sacrifices have taught scientists a lot about the outer limits of what you might call ultra-piquance.

To be clear: capsaicin is a neurotoxin, and consuming too much of it at any one time can definitely overwhelm your brain and body to a deadly point. Yes, capsaicin kills.

Capsaicin can kill off nerve cells. It can also kill intestinal parasites, bacteria, maybe even cancer cells. So that’s useful. On the other hand, it can also give you cancer, apparently, especially stomach cancer. It can induce hives, asthma attacks, seizures, strokes, and heart attacks; and it can help prevent the same.

In other words, the pattern is complex. Studies have yielded inconsistent results. The precise conditions under which chili heat is therapeutic are poorly understood, at least by modern scientists.

It’s not clear which is harder — to be killed by chili peppers or soothed by them.

So…if the heat from spicy peppers is fake, how does it kill you?

The heat is fake, but not the neurotoxicity. Of course, most people would have to eat a helluva load of peppers all at once to be in the danger zone. According to one enterprising study in 1980, about three pounds of hardcore chilis in powder form could do in a 150-pound person.

Maybe. Tell that to Wayne Algenio, 31, of Jamaica, Queens, the reigning champ of spicy brinkmanship. This 270-lb “competitive eater” set the world record in 2016 by consuming no less than 22 Carolina Reapers in one sitting (without having a seizure afterward). The runtish Carolina Reapers are more than just hardcore. No chili pepper variety on Earth is hotter than a Reaper, as of this writing; clocking in at more than 2.2 million Scoville heat units, these babies are practically weaponized. They come from South Carolina, the proud creation of Smokin’ Ed Currie of the PuckerButt Pepper Company.

We appreciate daredevils like Mr. Algenio for reminding us of that perennial truth of human-chili pepper relations: Chilis can kill, chilis can heal — but most importantly for masochistic mammals like us, chilis pack a hell of a thrill.