Generally, vaping cannabis flower and leaf is considered less risky than smoking cannabis leaves or flowers due to less toxic chemicals being inhaled. The long-term risks associated with smoking cannabis plant are similar to that of smoking nicotine, which are well documented. However, the damage to the lungs does not advance as quickly when smoking cannabis. While vaping is considered safer, the trend is in its infancy, and there is a lack of any long-time research as to the effect. The effect or “high” is more intense when vaping, creating risks around safety and judgment. Oil is generally thought to carry the least risk when purchased through legitimate sources, with illicit THC oil having devastating effects if contaminated with vitamin E acetate. An overview of the research in this area is presented below.
Cannabis Leaf & Flower Research
- The long-term risks of smoking cannabis include:
- By heating the cannabis plant to 180-200° C in an electric vaporizer, the cannabinoids on the surface of the cannabis leaf or flower are vaporized. This has been shown to produce substantial amounts of THC without toxic chemicals like benzene, toluene, and naphthalene, which are present when cannabis is smoked. The amount of carbon monoxide and tar generated is also considerably less than that generated by smoking cannabis.
- A pilot study in 2007 found that participants had higher blood concentrations of THC when vaping at the three strengths of cannabis tested (1.7%, 3.4%, and 6.8% THC) compared to smoking the same strength cannabis. Blood concentration levels were taken at 30 and 60 minute intervals. Interestingly, the self-reported high did not vary between smoking or vaping. However, the self-reported high increased at higher doses. Most participants preferred vaping to smoking the cannabis.
- Although smoking cannabis is thought to do less damage to a person’s lungs than smoking tobacco, it does do damage. A 2002 study found “Cannabis can lead to impaired driving skills, and heavy use in adolescence might create deviant brain structure as well as decreases in intelligence. A vaporizer offers no protection against these negative consequences. Nevertheless, a vaporizer has considerable potential for increasing cannabis drug safety by minimizing pulmonary troubles.”
- A 2010 study found after providing cannabis users with respiratory symptoms a vaporizer for a month, at the end of the month, “they wanted to continue using it after the month, that their respiratory problems decreased, and that two tobacco smokers decreased the number of tobacco cigarettes they smoked.”
- In a 2014 study, Cannabis users who vaped were surveyed as to the best reasons for vaping. The four most popular reasons were:
- The study concluded, “vaporizers are worthy of experimental research evaluating harm-reduction benefits of using them, as well as examination of possible risks, such as increased use of marijuana.”
Vaping Cannabis Oil Research
- Around 2017, there were a speight of cases similar to the one detailed in the case report of a 54-year-old male presented with acute onset dyspnea and hemoptysis. The dyspnea had developed six hours after vaping. The man had never smoked tobacco but had been vaping cannabis oil weekly for several years.
- When admitted, he had a blood oxygen saturation of just 82%. It rose to 91% on 6L of oxygen. A CT angiogram of the chest showed “extensive airspace opacification in a centrilobular nodular pattern roughly resembling a tree in bloom.”
- It was noted “cannabis oil vaping is a newer method of use; a prefilled cartridge of cannabinoid concentrated oil is loaded into a hand-held vaporizer, which has a battery-operated heating system. This method avoids vaporizing crude marijuana parts and is thought to be safer [than the leaf or flower].”
- The case study noted when discussing the risk of vaping, “Heating can also transform propylene glycol into carbonyls such as formaldehyde, a carcinogen, and respiratory irritant. Flavoring ingredients, including diacetyl, may also pose risks to respiratory health; although it is more recognized in e-cigarette use, it can be present in cannabis oil vaping.”
- Contaminants in the oil could not be ruled out as a cause in this and other similar cases. Research was undertaken to determine what was the cause of the acute lung injuries of vape users.
- One theory is inhaling the remnants of the butane oil used to extract the oil from the plant was causing the lung injury. A more popular theory is another additive Vitamin E acetate is responsible for the damage. Research completed subsequently is supportive of this theory. The addition of vitamin E acetate to product fluid began to appear in the illicit market in 2017 and 201, becoming increasingly popular in 2019.
Caution Around Vaping Risks
- Some research has expressed concern regarding the unknown quantity vaping presents; specifically, unlike tobacco, there is not a volume of research behind it as to the risks. This does not mean that in the future new risks will not be identified from the acute and long-term inhalation of aerosols emitted by vaping devices.
- Although vaporization removes many of the toxic chemicals associated with smoking cannabis, more research is required to determine vaping’s overall safety. Concerns have been raised that vaping is more likely to lead to more frequent and prolonged use of cannabis. The aforementioned benefits from the 2014 study could contribute to this increased prevalence or frequency.