Just How Much Heat Can One Mouth Take?

Slate tackles your burning questions about spicy food.

A person who is red in the face with steam coming out his ears.
Photo illustration by Slate. Photos by Getty Images Plus.

For an essential list of condiments—from mild to hot!—that will spice up your cooking, click here.

Chances are you’re one of millions who enjoy the nose-running, body-sweating, stomach-churning, mouth-burning effects of spicy food. Why do we, as a species, willingly (and enthusiastically) subject ourselves to this? What’s really happening to our bodies when we dig into the hottest curry on the menu?

Here are some explanations of what’s physically going on inside you when you load up on heat.

Can spicy food damage your tongue?

No, not when you ingest the amounts we typically consume in food. In fact, when you eat spicy food, you’re not burning your tongue at all—you’re a victim of a neurological response. When you take a bite out of a chile pepper, the pepper’s membranes release capsaicin, a chemical compound that clamps onto your mouth’s neurotransmitters, which regulate temperature. These are the same receptors that would tell the roof of your mouth, say, that it was being burned from a bite of scorching hot brick-oven pizza, but in the spicy food scenario, the receptors falsely alert you that you’re literally burning your mouth. These receptors exist all over your body, which also explains why you have a burning sensation on your fingers after chopping serrano peppers (or in your eyes if you absentmindedly rub them). But, according to Keith Cadwallader, a professor at the University of Illinois, there’s no damage to any tissue itself: The interaction is simply a signal that our brains interpret as a blast of heat. And it certainly doesn’t damage your taste buds, as the capsaicin doesn’t even interact with them. Spiciness isn’t a taste; it’s simply a pain response.

Why would I like something that’s a pain response?

Scientists haven’t fully figured out the answer to this question yet, according to Gary Beauchamp, a researcher at the Monell Chemical Senses Center and professor at the University of Pennsylvania, but they’ve proposed a few theories. It’s possible we have trained ourselves to like spicy food because along with the pain from that pop of Sriracha we get a little jolt of endorphins as our bodies try to curb the pain, or it might be that we become conditioned to like the sensations that accompany delicious and satisfying foods. Others speculate that we like it because it stimulates saliva production, which allows us to eat food more easily. Some have said it’s the same kind of psychological pleasure some people get from roller coasters: a physical thrill with no real risk of harm. It’s possible we like it because of indeterminate health benefits. Still others say spicy food enhances the flavor of salty foods. The real answer may be none of these, or several.

Huy Fong Sriracha Chili Hot Sauce.
Huy Fong Foods

What we do know is that spicy food only really appears to appeal to humans. It seems likely chile peppers produce capsaicin in part to deter other mammals from eating them. Infants naturally dislike the chemical, but at some point during adolescence, many children develop the taste for it. How much you end up liking spicy foods seems to be both cultural and individual: There’s evidence that some people naturally have higher tolerances, possibly because of genetics, according to Beauchamp. But again, even that is up for debate.

If I don’t like spicy food now, can I make myself like it?

Yep. There’s evidence that by exposing yourself to small doses of capsaicin, you’ll slowly adjust and build up a tolerance to spicy foods. The heat receptors in your mouth do build up an amount of resistance to it, and they become less responsive the more they are triggered, which is why some people notice they need twice as much Cholula as they once did. It appears to be easier to acclimate to it as a child, but adults can also work their way into tolerating higher levels of the chemical, ideally when placed with foods you already like.

Cholula hot sauce.

You can test this out in the shorter term, though. According to Linda Bartoshuk, a professor at the University of Florida Institute of Food and Agricultural Sciences, if you eat a jalapeño pepper, the burning sensation will subside in 15 minutes, but the residual effect of that encounter will last a couple days. During those two days, you can try other spicy foods, and they will seem less spicy than they normally would.

Why do I suddenly start sweating when I eat spicy foods?

When your brain gets the signal that there’s a fire in your mouth, it reacts with its own methods for cooling itself down: sweating and breathing rapidly. You’ll also start producing more mucus, saliva, and tears, which is the body’s effort to purge itself of the chemicals causing the pain.

What about hiccups?

Because the pain receptors that capsaicin triggers exist throughout your body, spicy foods can cause discomfort all through digestion. They can cause a burning sensation when they latch onto the receptors on the lining of your esophagus, then more discomfort and cramping in your stomach, and, yes, even a burning sensation on the way out. But it may also cause hiccups for some people: When capsaicin inflames the nerve that passes motor information to the diaphragm to help us breathe, it can cause involuntary spasms—hiccups.

How do I get the burning in my mouth to stop?

Room temperature water, as you might know from experience, doesn’t help that much. That’s because the water only spreads things around. But very icy water may help, as, again, your mouth interprets the spiciness as temperature heat. Studies also show that capsaicin dissolves in fat, alcohol, and a protein found in dairy, so the tip to have a glass of milk nearby is solid advice. But fatty foods will also do the trick.

So even really intense peppers don’t do any harm to your body?

Well, there are reports of some people, in a few anecdotal cases, getting injured during extreme chile pepper–eating contests. It seems likely that these injuries mostly come from the shock of the experience, but in at least a couple instances, eating extremely spicy food has been thought to be responsible for spasms in arteries that led to nonfatal heart attacks and a thunderclap headache. At high enough concentrations, capsaicin can harm you by blocking the production of certain neurotransmitters, making it so nerve cells can’t communicate with one another, but your body will prevent you from consuming that much of the chemical by vomiting and otherwise sending you the unavoidable signals that it is rejecting the substance you are putting in your body.

In terms of discomfort, you can get diarrhea when your body overproduces gastric mucus, causing your digestion rate to speed up too much. Those are unpleasant but ultimately minor effects, but if you already have underlying problems such as stomach ulcers, ulcerative colitis, Crohn’s disease, IBS, or Celiac disease, you can experience a temporary worsening of your symptoms. For some susceptible people, breathing in capsaicin could lead to an asthma attack or other respiratory distress. But in general, while exposure to extreme chiles can be uncomfortable and often painful, they’re not harmful for your health.

OK, I’m feeling bold. What’s the hottest pepper I can try?

Peppers’ capsaicin levels are measured on the Scoville scale, which offers a gauge for relative spiciness. There’s no upper limit to the scale (bell peppers sit right at zero), but Guinness World Records says the highest point right now is set by the Carolina Reaper, which clocks in at 1.6 million Scoville Heat Units or SHU (you can get a far less stomach-upsetting taste of the pepper in hot sauce form).

Reaper Sling Blade Hot Sauce.
Reaper Sling Blade Hot Sauce

By comparison, Sriracha and Tabasco sauces are generally measured around a meager 2,000 SHU. Jalapeños range from 2,500 to a little over 8,000 SHU, whereas a really spicy habanero will reach about 500,000 SHU.

The Carolina Reaper’s run as Guinness’ world’s hottest pepper may soon come to an end. Two other peppers claim to be hotter: Dragon’s Breath, at 2.5 million SHU, and Pepper X at 3.2 million SHU. Given that the Carolina Reaper, only half as hot as Pepper X, once sent a man to the hospital, it’s safe to say you shouldn’t try either of those without first figuring out your limits.