One at a time, 48 university students in Chongqing, China, placed an entire cube of chili-laced gelatin in their mouths. For five minutes, they were told not to chew or swallow. Then they spat it out, rinsed twice, and, after a one-minute break, received 40 brief laser pulses to the back of their left hand.

Five to seven days later, each participant came back and repeated the experiment with a non-spicy gelatin cube.

When researchers compared the two sessions, participants rated the stronger laser pulses as less painful and less unpleasant after holding the spicy cube. The chili made no significant difference during the milder pulses.

Published in Physiology & Behavior, the study explores a counterintuitive possibility. The burning sensation created by chili may temporarily help the nervous system dampen a second, stronger source of pain elsewhere in the body.

How Spicy Food Changed High-Intensity Pain

Before starting the main experiment, the team tested its chili-gelatin recipe on 30 other volunteers. They rated the burn at 5.2 on a seven-point scale, making it noticeably strong but still tolerable. Everyone finished the test, and no one found the burn unbearable.

Each cube used in the main study contained about 1.5 milligrams of capsaicin, the compound that gives chili peppers their heat.

Rather than use the same laser setting for everyone, researchers adjusted it for each participant. One level was meant to feel like about four out of 10, while the other aimed for seven. Each laser pulse lasted only four milliseconds, but participants received 20 at each level.

After the non-spicy cube, participants gave the stronger pulses an average pain rating of 5.45. That fell to 5.13 after chili. Ratings for how unpleasant the pulses felt also dropped from 2.50 to 2.15.

Why a Burning Mouth May Make Another Pain Feel Weaker

Capsaicin and intense heat activate some of the same pain-sensing pathways, including receptors called TRPV1. The researchers think the burning mouth may have switched on the body’s internal pain-control system.

Researchers call this conditioned pain modulation. It means one painful sensation can sometimes weaken another by activating signals from the brain that turn down incoming pain messages.

The chili didn’t seem to help simply by putting people in a better mood. Participants reported similar emotional states during both sessions.

A burning mouth is also hard to ignore. While it lingered, participants may just have paid less attention to the laser. Because the study didn’t track attention, researchers can’t tell how much of the effect came from the body’s pain-control system and how much came from distraction.

Liking Spicy Food Was Linked to Lower Self-Reported Pain Sensitivity

People who said they liked spicy food generally described themselves as less sensitive to pain and less afraid of it. Those who preferred their food hotter also tended to report lower sensitivity.

But that pattern came from questionnaires. It didn’t line up with how participants responded during the laser calibration, so the study doesn’t show that spice lovers can physically withstand more heat.

It also doesn’t prove that eating chili builds pain tolerance. People who are naturally less bothered by pain may simply be more drawn to spicy food. Culture, experience, personality, or biological differences could influence both.

All 48 participants were healthy young adults from China, and the experiment involved short bursts of pain in a controlled lab. The results could look different during an injury, medical procedure, or chronic pain condition. They also don’t mean chili should be treated as a painkiller.

Opioids remain one of the most reliable tools for treating serious pain, but their risks have pushed researchers to keep searching for other ways to help the body dampen it. For the volunteers in this experiment, exploring one possibility meant five uncomfortable minutes with chili gelatin, a rinse of water, dozens of laser pulses, and about $14 for their trouble.

This article is not offering medical advice and should be used for informational purposes only.

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Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• This article references information from a study published in Physiology & Behavior:Acute spicy stimulation reduces laser-induced heat pain perception in healthy adults