Delta-8 tetrahydrocannabinol (THC) is a hemp-derived cannabinoid popular for its psychoactive effects, which are generally milder than Delta-9 THC. A common complaint among users is the harsh and persistent cough it causes when vaped. This severe respiratory irritation results from a combination of the compound’s physical properties, undisclosed contaminants, and the user’s interaction with the delivery device.
Why Cannabinoid Vapor Irritates the Lungs
The primary reason for the coughing reflex is the introduction of highly concentrated foreign material into the sensitive lower airways. Concentrated vapor bypasses the natural filtering mechanisms of the upper respiratory tract and is inhaled directly into the bronchi and alveoli. This foreign particulate matter irritates the mucosal lining of the lungs, triggering the protective cough mechanism to clear the airways.
Cannabinoid vapor is significantly dry, and this lack of moisture aggravates the throat and bronchial tissue. When the airway lining becomes dehydrated, it becomes more reactive, interpreting the inhaled aerosol as a threat. The chemical nature of Delta-8 THC also suppresses saliva production, leading to a dry mouth and throat that further exacerbates the cough reflex.
Another element is the thermal degradation of cannabinoids and terpenes in the vape oil, which produces irritating chemical byproducts. Terpenes, added for flavor, can break down into aldehydes like acrolein when overheated. Acrolein is a pungent airway irritant that activates sensory channels in the throat, leading to a forceful cough. The heat applied during vaporization inevitably creates these complex mixtures of irritants.
Cutting Agents and Product Contaminants
A primary source of severe coughing is the presence of undisclosed additives and contaminants in unregulated Delta-8 products. Lack of federal oversight allows manufacturers to use cheap cutting agents to dilute the product or increase volume. These additives are often unsafe for inhalation, even if harmless when ingested orally.
Dangerous Cutting Agents
One notorious cutting agent is Vitamin E acetate, which caused the E-cigarette or Vaping Use-Associated Lung Injury (EVALI) crisis. When inhaled, this oil-based compound coats the alveoli, leading to lipoid pneumonia and severe respiratory distress. While less common, other lipid-based fillers like Medium Chain Triglyceride (MCT) oil are sometimes used. MCT oil is highly dangerous to vape because heating it above 230°C produces toxic compounds like formaldehyde and acetaldehyde.
Common Thinning Agents and Residuals
Other common thinning agents are Propylene Glycol (PG) and Vegetable Glycerin (VG), the base liquids in most nicotine vapes. PG is classified as a respiratory irritant, and both PG and VG can degrade into irritating carbonyl compounds when subjected to high heat.
Another element is the chemical process used to synthesize Delta-8 THC from hemp-derived CBD, which involves strong acids and solvents. If the final product is not properly purified, residual solvents (like ethanol or heptane) or trace heavy metals from cheap hardware can remain. These cause chemical irritation that triggers coughing and poses a long-term health risk.
Inhalation Style and Device Temperature
The physical act of vaping and the temperature setting on the device are significant, user-controlled factors contributing to coughing fits. Vaping at high wattages or temperatures causes the oil and carrier agents to heat up too quickly, leading to thermal degradation. This rapid heating generates a higher concentration of irritating byproducts, such as aldehydes and phenols. Using a lower voltage or temperature setting can produce a smoother vapor by minimizing this thermal breakdown.
Inhalation technique also directly influences the severity of the cough reflex. Taking a long, deep, or rapid pull overwhelms the lungs’ capacity to process the concentrated vapor. This large volume of dense, dry vapor is interpreted by the airways as an immediate threat, triggering a powerful, protective cough reflex. Users can mitigate this reaction by taking shorter, gentler puffs and allowing the vapor to cool slightly before it reaches the lungs.