Electronic vaporizers (vapes) heat a liquid, known as e-liquid or vape juice, to create an aerosol for inhalation. Nearly all e-liquids include two primary ingredients: propylene glycol (PG) and vegetable glycerin (VG). The question of whether one can vape pure VG stems from its status as a widely used base component. This article explores VG’s functions in standard mixtures, the practical challenges of using it purely, and the potential health consequences associated with inhaling heated VG aerosol.
Glycerin’s Role in Standard Vaping Liquids
Vegetable glycerin (VG) is a clear, odorless, and slightly sweet liquid derived from plant oils, such as palm, coconut, or soy. In vape juice, VG acts as a base, primarily responsible for the density and volume of the visible vapor cloud produced when heated. VG has a thick, syrupy consistency, which gives the e-liquid its overall viscosity. A higher VG ratio contributes to a smoother inhalation experience, offering a gentler sensation in the throat compared to the sharper “throat hit” associated with PG. VG also subtly enhances the flavor profile due to its inherent mild sweetness. Manufacturers blend VG and PG in varying ratios, balancing VG’s smooth vapor production against PG’s stronger flavor-carrying capacity. For example, liquids with a high VG content (e.g., 70% VG) are favored by users who prioritize dense vapor clouds, and the ratio influences performance in different hardware.
Practicality of Vaping Pure Glycerin
While it is possible to vaporize pure vegetable glycerin, it presents practical difficulties for most standard vaping equipment. The main issue is the extreme viscosity of 100% VG, which is similar to a thick syrup. This dense consistency greatly impedes “wicking,” the process by which the liquid travels to saturate the coil’s heating element.
The slow wicking rate means the cotton material around the coil may dry out quickly, especially with frequent use or high-power settings. When the cotton is not fully saturated, the coil can overheat and combust the remaining VG, leading to an unpleasant and harsh “dry hit.” This overheating also causes rapid degradation of the coil and requires more frequent replacement.
Pure VG provides a minimal “throat hit” and is not an efficient carrier for flavorings, which are more soluble in PG. Vaping pure, unflavored VG often results in a very subtle, slightly sweet taste and lacks the satisfying sensation many users expect. Commercially available “pure VG” liquids often contain a small percentage of distilled water or minimal PG to reduce viscosity and aid wicking.
Health Implications of Inhaling Heated Glycerin
The health concern related to inhaling heated VG centers on the potential for thermal decomposition. When vegetable glycerin is subjected to excessive heat, it can break down into toxic chemical compounds. One byproduct of this thermal degradation is acrolein.
Acrolein is a highly reactive aldehyde that strongly irritates the respiratory system. Studies confirm that acrolein is generated from the thermal decomposition of VG within e-cigarette aerosols. This compound causes airway inflammation and can disrupt the function of ion channels in the airways.
Inhaling VG aerosol can also cause immediate physical effects because VG is a humectant, a substance that attracts and retains moisture. This means VG can draw water from the mouth, throat, and respiratory tract, potentially leading to dry mouth and throat irritation, which necessitates increased water intake. Chronic inhalation of VG aerosol has been linked to respiratory issues, including symptoms consistent with chronic bronchitis and lung inflammation.