As vaping cannabis grew in popularity a couple of years ago, so too did concerns about its safety. Between August 2019 and February 2020 a total of 2,807 hospitalizations and deaths occurred as a result of vaping-related lung injuries, with the finger of blame pointing firmly at vitamin E acetate, an additive common in street-purchased or home-mixed THC e-liquids.
But while the Centers for Disease Control and Prevention says vitamin E acetate does indeed seem to be the cause of the most egregious lung injuries, a new study suggests there may be other components, including in mainstream vaped cannabis products, that could harm the lungs.
The research published in Inhalation Toxicology, the journal of the International Forum for Respiratory Research, found that one of the toxic ingredients is phytol — a terpene — and that it may have more detrimental effects than polypropylene.
Both of these can be used as thinning agents for cannabis extracts, but phytol is often thought of as more innocuous as it is a naturally-occurring terpene known for being an antioxidant. Most notably it is found in green tea but is also naturally found in some marijuana varieties, including Cheese and Sour Diesel.
In the study, researchers exposed male and female rats to 5 milligrams per liter of phytol or propylene glycol for periods of up to six hours over a span of up to two weeks.
The rats exposed to phytol showed several severe clinical changes, including weight loss, harm to respiratory tissues and even death. In fact the phytol effects were so pronounced the trial for those rats was halted.
By comparison, the rats exposed to propylene glycol showed no adverse reactions after 14 days of high-dose exposure.
The study was commissioned by Canopy Growth USA, LLC (CG) with the intent of comparing two potential excipients for their cannabis product portfolio. Experiments were designed, performed, and interpreted independently by Lovelace Biomedical scientists without influence from CG.