The sensation of harshness or a “burn” when using nicotine products, particularly vapes and traditional cigarettes, is a common experience. While the feeling may be intense and cause a scratchy sensation, it is not typically a thermal burn but rather a chemical irritation of the throat and airways. This irritation, often called a “throat hit,” is a combined effect involving the concentration and chemical form of the nicotine, the properties of the delivery ingredients, and the temperature of the inhaled aerosol or smoke. Understanding these factors reveals why some nicotine products feel much harsher than others. The chemistry of nicotine and the non-nicotine ingredients are the primary drivers behind this distinct sensation.
Nicotine Concentration and Alkalinity
Nicotine is chemically an alkaloid, meaning it is a basic, or alkaline, substance. Higher concentrations of nicotine lead to a more pronounced, harsher sensation, as the nicotine stimulates pain receptors in the throat and airways. The chemical structure of the nicotine largely determines how irritating it feels.
Standard freebase nicotine is highly alkaline, possessing a higher pH level. This elevated alkalinity causes the sharp, abrasive feeling at the back of the throat, especially when vaped at higher concentrations. Freebase nicotine is the form traditionally used in older e-liquids and delivers a strong throat hit that users often associate with smoking a traditional cigarette.
Nicotine salts are created by neutralizing freebase nicotine with an acid, such as benzoic acid, which lowers the compound’s pH. This modification makes the nicotine far less alkaline, allowing it to be inhaled smoothly with significantly reduced harshness, even at very high concentrations. This difference is why products containing nicotine salts can deliver high nicotine doses without the intense burning sensation characteristic of high-concentration freebase nicotine.
Non-Nicotine Ingredients Causing Irritation
Beyond the nicotine itself, the substances used to deliver the nicotine are a major source of throat irritation. Propylene Glycol (PG) is a common component in e-liquids, serving as a humectant and flavor carrier. PG is known for its hygroscopic properties, meaning it absorbs moisture.
When PG is inhaled, it draws moisture from the delicate mucosal lining of the throat and mouth, leading to dryness and a scratchy, sore feeling. This scratchy sensation, particularly in e-liquids with a high PG ratio, is often mistaken for a nicotine burn. Vegetable Glycerin (VG), the other primary e-liquid ingredient, is much thicker and associated with a smoother, gentler throat sensation because it is less irritating and less drying than PG.
Certain flavorings and additives can also contribute to localized irritation. Chemicals like cinnamaldehyde and cooling agents, such as menthol, stimulate specific receptors in the mouth and throat, creating sensations ranging from a cooling tingle to a mild burning. Furthermore, excessive heat from the delivery device, often due to high wattage settings or a “dry hit” where the coil overheats, can physically irritate the tissue and cause a burning feeling.
Physiological Impact of Throat Irritation
The harsh sensation felt in the throat is a direct physiological response to chemical irritants. The primary mechanism involves stimulating sensory nerves, specifically the Transient Receptor Potential Ankyrin 1 (TRPA1) receptors, which detect environmental irritants. When alkaline nicotine or desiccating PG contacts the throat lining, these receptors activate, sending pain and irritation signals to the brain.
This chemical stimulation causes mild inflammation and dehydration of the mucosal lining, which is the protective tissue covering the throat. Repeated exposure to these irritants can temporarily affect the throat’s natural cleaning mechanisms, including the function of cilia, the tiny hair-like structures that sweep foreign material away from the lungs. Nicotine-containing vapor has been shown to reduce the volume of airway surface liquid and increase mucus viscosity in a dose-dependent manner, further impairing this crucial function.
For most users, the sensation is one of temporary irritation, and the symptoms, such as a dry or sore throat, often subside quickly after use or with hydration. However, persistent exposure to these irritants can potentially lead to chronic issues like a persistent cough or dryness. The irritation is a clear signal that the body is reacting to the presence of foreign chemicals or excessive heat.
Strategies for Reducing Throat Harshness
Users who experience discomfort have several options to minimize the harshness of their nicotine product use.
Nicotine Concentration and Form
Adjusting the nicotine concentration is an effective first step, as lowering the strength directly reduces the amount of alkaline irritant inhaled. If a higher nicotine dose is still desired, switching from standard freebase nicotine to a nicotine salt formulation will dramatically smooth the throat hit due to the lower pH level.
E-Liquid Composition
Modifying the Propylene Glycol (PG) and Vegetable Glycerin (VG) ratio in e-liquids can also provide relief. Choosing a liquid with a higher VG content, such as 70% VG or more, will reduce the drying effects of PG. This results in a significantly smoother and less scratchy inhale, reducing irritation often confused with a nicotine burn.
Hydration and Device Settings
Since PG is a humectant that draws moisture from the body, staying well-hydrated is an important strategy to combat throat dryness and irritation. Drinking water helps to replenish the moisture in the mucosal lining that is depleted by the inhaled vapor. Finally, reducing the power or wattage settings on a vaping device will lower the temperature of the aerosol produced, preventing the physical burning sensation that comes from overheating the e-liquid.