Revealing the Potential Risks of Cannabis Dabbing

In a recent publication, researchers from Portland State University, Oregon detail the degradation of key cannabis compounds that occurs during dabbing. A rapidly growing trend in cannabis use, dabbing involves heating a small amount of cannabis extract (a dab) with a nail and then inhaling the resultant vapors. The group's research aimed to gauge the safety of this trending practice, and whether its delivery of high volumes of cannabinoids, potential contaminants and chemically degraded versions of both represents a potential danger to consumers.

The study focused on the degradation of terpenoids, compounds that the research group predicted may break down into toxic products when heated. To achieve their aims, the group accurately recreated the inhalation topography and temperatures employed by users. Their findings were published in ACS Omega.

The need-to-know facts of dabbing

So why is dabbing on the rise? According to one survey, users find that dabs require less material to get the desired effect and a ‘cleaner high’. Many regard the practice as a form of vaporization, and so consider it easier on the lungs than smoking. However, it's important to note that there are little concrete data on the actual prevalence and chemistry of dabbing.

To achieve a dab requires the use of a nail, which is often an electrically controlled nail (e-nail) that allows temperature control. Or, consumers use a ceramic/titanium/quartz nail heated with a crème brûlée torch, which is unlikely to produce a consistent temperature.

The prime extract used in dabbing is butane hash oil (BHO). A non-polar cannabis extract, BHO's tetrahydrocannabinol (THC) and cannabidiol (CBD) contents range from 50 to 90%, while terpene content can be between 0.1 to 34%. As if that content weren't high enough, some users choose to dip their BHO in a vial of terpenes prior to use, often known as terp dipping.

BHO is created by pouring butane over cannabis buds and then ‘purging’ the buds in an oven or a vacuum at room temperature in order to remove the butane. Although often produced in clandestine, unregulated environments, through the course of legalization, BHO production has steadily become more standardized, to the point where professional laboratories meet OSHA standards. As the temperature used in this process isn't hot enough to decarboxylate the delta-9-tetrahydrocannabinolic acid (THCA) into active THC, the BHO isn't orally active and must be vaporized for a user to experience its desired effects.

Dabbing’s toxic products

Recreating the conditions of typical dabbing practices, the researchers investigated the effects of different dabbing temperatures on the degradation of terpenes into methacrolein (MC) and benzene.

These product compounds were of interest to the researchers as they are both regarded as pollutants. Similar in structure to acrolein, a pulmonary irritant, MC has been shown to cause damage to the respiratory tracts of mice and it’s been recommended that humans shouldn’t be exposed to levels exceeding 0.3ppm. Although it should be noted that research into MC’s adverse effects is still thin and conflicting reports indicate that safe levels are yet to be truly determined.

The toxicology of benzene, on the other hand, is universally agreed. A carcinogen, it has been named by some as “the largest single air toxic pollutant in terms of cancer risk in the US”. 

The potential degradation of terpenes into these harmful contaminants is particularly concerning as terpenes are now highly prized within inhalable cannabis compounds.  In fact, they are often regarded as having a complementary effect for the user, a phenomenon that’s been dubbed the entourage effect. It’s worth noting that, terpenes are not only regularly added to cannabis products, but flavored electronic cigarettes too. 

Analyzing dabs

Given the wide diversity of the terpenes present in BHO, the team chose myrcene, an abundant terpene, as a model.

Despite the difficulty in generating consistent temperatures, the researchers used a heated ceramic nail to dab, in order to best reflect common dabbing practices. In addition, the group dabbed myrcene at four different temperature ranges to capture the full array of temperatures used by those who dab. 

The results

The researchers’ results clearly demonstrated that dabbing results in the production of toxic degradation products which may cause significant harm to users. 

MC levels were significantly higher when higher dabbing temperatures were used, and benzene wasn’t even detected below the highest temperature range. These results suggest that the higher dabbing temperatures preferred by users could be generating more harmful pollutants than lower temperatures.

In addition, during Gas Chromatography-Mass Spectrometry (GC-MS) analysis, myrcene and other terpenes displayed significant peaks linked to isoprene. This suggests that the terpenes present in BHO may break down into their isoprene monomers before further degradation. 

This result indicates that terpene degradation may be even more dangerous to users than first thought. Studies into the atmospheric chemistry of isoprene have shown that it reacts with hydroxyl radicals and O2 to form not only MC but other pollutants such as methyl vinyl ketone and 3-methylfuran. Indeed, GC–MS analysis proved that each pure terpene had a high match quality with MC, methyl vinyl ketone, and 3-methylfuran, as well as 1,3-butadiene and several cyclic and acyclic dienes, polyenes, and aromatics.

If the results weren't concerning enough, the researchers also argue that the recorded MC and benzene were likely underestimated. This may be due to the use of myrcene as an extrapolation model, which affords the lowest yield of degradation products of all of the terpenes investigated.

The dangers of dabbing

Thanks to the research of Portland State University, the toxic products of dabbing and, specifically, the popular extract BHO is now better understood. Users who practice this form of vaporization may risk exposing themselves to the pulmonary irritants methacrolein and benzene. Moreover, those who frequently use higher dabbing temperatures or who have difficulty in controlling the nail temperature put themselves at a greater risk of exposure to these toxins. The researchers also highlight the potential dangers of infusing flavored electronics cigarettes with terpenes, but suggest more research is required for clarification.