Capsaicin is the active chemical compound in chili peppers that creates the sensation of heat. This burning feeling is not an actual thermal burn but a chemical reaction that triggers the body’s pain response. The duration of this discomfort varies widely, depending on the pepper’s potency and the area of the body exposed. Understanding how this molecule interacts with the nervous system is key to knowing why the burn persists and how to stop it effectively.
How Capsaicin Tricks Your Body
Capsaicin is a potent irritant that binds directly to a specific protein receptor found in the nerve endings, called Transient Receptor Potential Vanilloid 1 (TRPV1). This receptor is a specialized ion channel primarily responsible for detecting actual heat and physical abrasion.
When capsaicin binds to the TRPV1 receptor, it forces the channel to open, allowing positive ions, such as calcium and sodium, to flow into the neuron. This influx of ions depolarizes the nerve cell, signaling the brain that the body is experiencing scalding heat. The brain interprets this chemical signal as a painful, thermal burn, even though the temperature has not changed. Capsaicin is highly lipophilic, meaning it is fat-soluble, which allows it to pass easily through the cell membrane.
Key Factors Determining Burn Duration
The primary factor dictating how long the burn lasts is the concentration of capsaicin, which is measured using the Scoville Heat Unit (SHU) scale. Higher SHU ratings indicate a greater concentration of capsaicinoids, leading to a more intense and prolonged binding to the TRPV1 receptors. For instance, a mild jalapeño burn (2,500–8,000 SHU) typically resolves much faster than exposure to a super-hot pepper, which can exceed one million SHU.
The location of exposure also significantly influences the duration of the discomfort. In the mouth, where the capsaicin is mixed with saliva, a mild burn usually lasts only 15 to 30 minutes, though it can persist up to an hour with hotter peppers. Burns on the skin, such as on the hands after chopping peppers, can last much longer, with typical discomfort ranging from 20 minutes up to 12 hours if not removed properly. This is because capsaicin is a persistent, oil-based compound that adheres stubbornly to the skin’s surface and absorbs slowly.
Exposure to mucous membranes, such as the eyes, is the most severe and longest lasting, with intense burning often persisting for one to three hours. The longer capsaicin remains on the skin without effective removal, the more it is absorbed, potentially causing a recurrent burning sensation that can last for hours or even days. Failure to use a proper solvent simply spreads the oil-based compound, extending the duration of the pain.
Immediate and Effective Relief Strategies
Since capsaicin is non-polar and oil-based, water alone is ineffective and can actually spread the compound, worsening the sensation. Effective relief strategies rely on substances that can chemically dissolve the oil or physically pull the capsaicin away from the nerve receptors.
High-fat dairy products, such as whole milk, yogurt, or sour cream, work because they contain a protein called casein. Casein is a fat-binding agent that binds to the capsaicin molecule, stripping it away from the TRPV1 receptors and allowing it to be washed away. Applying these fatty dairy products directly to the affected area or holding them in the mouth provides rapid relief within minutes.
For burns on the skin, mechanical removal using a degreasing agent is the most effective first step. Dish soap, which is formulated to break down fats and oils, works better than regular hand soap by emulsifying the capsaicin oil. Rubbing a cooking oil, like olive or vegetable oil, onto the skin before washing with dish soap can also help dissolve the capsaicin due to the principle of “like dissolves like”.
Using cold water or ice can provide temporary relief by cooling the nerve endings and reducing the intensity of the signal to the brain. However, this only soothes the symptom and does not remove the capsaicin itself. In cases of severe exposure, especially to the eyes or if blistering or respiratory distress occurs, seeking immediate medical attention is necessary.