In the context of vaping, “ice” does not refer to frozen water but describes a strong cooling sensation added to an e-liquid flavor. This term signals the presence of a chemical additive that creates a chilling effect in the mouth and throat upon inhalation. The primary purpose of this additive is to enhance the sensory experience of the vapor, making it feel crisp and refreshing, similar to breathing in cold air. This cooling sensation is often paired with fruit or candy flavors, leading to product names like “Strawberry Ice”.
The Ingredients Behind the Chill
The chill sensation in vape products is created by adding specific chemical compounds to the e-liquid formula. Traditional cooling comes from menthol, a naturally occurring compound from mint plants that imparts both a cooling effect and a distinct minty flavor. The modern “ice” effect, however, is largely achieved using synthetic cooling agents, primarily compounds known as WS-23 and WS-3. These synthetic agents were developed to provide a cooling sensation without the characteristic mint or herbal taste of menthol.
WS-23, often referred to as Koolada, is popular because it is essentially tasteless and odorless, allowing it to be added to non-mint flavors without altering their profile. This use of non-menthol coolants enables manufacturers to market products that feel cool but may bypass flavor regulations aimed at traditional menthol. WS-23 provides a clean, immediate cooling impact felt mostly at the back of the mouth and throat, offering a different sensory experience compared to menthol’s prominent flavor.
How the Cooling Sensation Works
The perception of coldness is not due to a drop in the vapor’s temperature; instead, it is a biological trick played on the sensory nervous system. Menthol and synthetic coolants like WS-23 work by interacting with the Transient Receptor Potential Melastatin 8 (TRPM8) receptor found in nerve endings. This receptor is the body’s primary cold sensor, normally activated by temperatures below 28°C (82°F). When the chemical cooling agent binds to the TRPM8 receptor, it activates the nerve cell, sending a signal to the brain that is interpreted as a chilling sensation. The effect is purely sensory, offering a feeling of clear or smoother inhalation, but it does not physically change the temperature of the vapor.
Regulatory Status and Specific Health Concerns
The regulatory status of synthetic cooling agents like WS-23 and WS-3 is complicated because they are often classified as food additives, which does not guarantee safety for inhalation. Inhalation safety data for these compounds is still developing, and there is a significant gap in knowledge regarding the health effects of daily exposure through vaping. Research indicates that these coolants are being used in e-cigarettes at levels that may exceed safety thresholds set by the World Health Organization for organ toxicity.
A major concern is that the cooling effect can mask the harshness and irritation of high nicotine concentrations or other irritants in the vapor. This masking effect can facilitate deeper and more frequent inhalation, which may lead to greater nicotine delivery and dependence. Studies have detected high levels of WS-23 in popular disposable e-cigarettes, with exposure models suggesting a low Margin of Exposure (MOE) below the recommended safety margin for organ toxicity. Regulatory bodies are increasingly scrutinizing these coolants, as their lack of a traditional flavor profile may allow them to circumvent flavor bans intended to reduce product appeal.