Inhalable, noncombustible cannabis products are playing a leading role in the use of the medical and recreational cannabis products. Specifically, the practice of “dabbing” has exponentially grown in popularity in states where medical and recreational cannabis consumption has been legalized.
Dabbing involves inhaling vapors produced by placing a small amount of cannabis extract (a “dab”) on a small heated surface (the “nail”), which is connected to a water pipe ( 1 ). The most popular dabs are known as butane hash oil (BHO) dabs mainly because the concentrate is produced by passing the solvent butane over cannabis buds and leaves ( 2 ). Butane is subsequently removed from the extract under vacuum at room temperature or by heating in an oven. Differences in processing can lead to different dab consistencies that are colloquially known as shatter, budder, crumble, pull-and-snap, wax, etc (3, 4).
BHO have a tetrahydrocannabinol (THC) and cannabidiol (CBD) concentrations ranging between 50 and 90% (2). Consumers consider dabbing to be a form of vaporization, and, therefore, view it as easier on the lungs than smoking ( 5).
While delivery of harmfully-large amounts of cannabinoids (Pierre) may represent a potential danger to consumers, little is known about the toxicants that the process may produce. According to a recent paper entitled “Toxicant formation in dabbing: the terpene story (4) by a group of Portland State University researchers the high heat commonly used to heat dabs (concentrated cannabis extracts) exposes users to high levels of methacrolein (lung, throat and eye irritant), benzene (carcinogen) and other potential toxic degradation products which are known to pose human health risks (4).
The authors determined that the source of the potentially harmful degradation products may be the terpenes (compounds that give cannabis its odor and flavor) that are routinely concentrated in BHO dabs (4). Myrcene is the most abundant terpene in cannabis, followed by limonene, linalool, pinene, caryophyllene, and humulene (4). Also, cannabis can contain trace amounts of up to 68 other terpenic compounds (6). Terpene content in BHO can range from 0.1 to 34% (4).
Another potential health risk is residual butane (a known carcinogen) that can be left behind if BHO dabs are not processed correctly (1, 2). Because of this, CO2 oil (another extraction method for dabbing) and alcohol extracts are the only allowable medical extracts to be sold under medical cannabis regulations in New York, Minnesota, Ohio and Pennsylvania (4). While commercially prepared BHO is on the rise in mature markets like California and Denver, much HBO is still made via “backyard-chemist” style operations so users beware.
Finally, while the results of this study are intriguing, I believe that much more research will be required to determine whether or not high heat terpene breakdown products pose actual health risks to dabbers.
- Stogner JM, Miller BL. The dabbing dilemma: A call for research on butane hash oil and other alternate forms of Cannabis. Subst. Abuse 2015; 36:393– 395
- Stogner JM, Miller BL. Assessing the dangers of “dabbing”: mere marijuana or harmful new trend? Pediatrics 2015: 136: 1– 3
- Pierre JM, Gandal M, Son M. Cannabis-induced psychosis associated with high potency “wax dabs” Schizophr. Res. 2016; 172:211– 212
- Meehan-Atrash J, Luo W, Strongin RM. Toxicant formation in dabbing: the terpene story ACS Omega, 2017; 2:6112–6117
- Gieringer D, St. Laurent J, Goodrich S. Cannabis vaporizer combines efficient delivery of THC with effective suppression of pyrolytic compounds J. Cannabis Ther. 2004; 4:7 – 27
- Ross SA, ElSohly MA. The volatile oil composition of fresh and air-dried buds of Cannabis sativa J. Nat. Prod. 1996: 59:49– 51