Vaporizer (cannabis) - Scientific Study

Scientific Study

Studies have shown that vaporizing cannabis exposes the user to lower levels of harmful substances than smoking cannabis. Substantial reductions were also found for the M1-volatizer.

A study published in the Journal of Psychopharmacology in May 2008 investigated the acceptability and usefulness of intrapulmonary THC administration using a vaporizer and pure THC instead of cannabis. Rising doses of THC (2, 4, 6 and 8 mg) were administered with 90 minutes intervals to twelve healthy males. Very low between-subject variability was observed in THC plasma concentrations, characterizing the vaporizer as a suitable method for the administration of THC.

In 2007 a study by University of California, San Francisco published in the Journal of the American Academy of Neurology examined the efficacy of a vaporizer that heats cannabis to a temperature between 180 °C (356 °F) and 200 °C (392 °F) degrees and found:

Using CO as an indicator, there was virtually no exposure to harmful combustion products using the vaporizing device. Since it replicates smoking's efficiency at producing the desired THC effect using smaller amounts of the active ingredient as opposed to pill forms, this device has great potential for improving the therapeutic utility of THC.

In 2006 a study performed by researchers at Leiden University tested a vaporizer with preparations of pure THC and found that:

Our results show that a safe and effective cannabinoid delivery system seems to be available to patients. The final pulmonal uptake of THC is comparable to the smoking of cannabis, while avoiding the respiratory disadvantages of smoking.

When using plant material (crude flower tops), besides THC, several other cannabinoids and a range of other plant components including terpenoids were detected in the plant material. However, using pure THC in the vaporizer, no degradation products (D8-THC, CBN, or unknown compounds) were detected by HPLC analysis. Also, a substantially larger fraction of the THC was delivered to the vapor by using pure THC.

Analysis of the vapor from the vaporizer found that using multiple passes it delivered 36%–61% of the THC in the sample. A study using pure cannabinoid preparations achieved a maximum of 54%. Studies of cannabis cigarettes smoked via a smoking machine under varying conditions of puff duration and air speed found very similar efficiencies of 34% to 61%. Consequently, users can achieve the desired effect with a similar amount of material as when smoking.

In a 2001 study, researchers found that "it is possible to vaporize medically active THC by heating marijuana to a temperature short of the point of combustion, thereby eliminating or substantially reducing harmful smoke toxins that are normally present in marijuana smoke." The unit produced THC at a temperature of 185 °C (365 °F), while eliminating three measured combustion products, benzene, toluene and naphthalene. Carbon monoxide and smoke tars were also reduced, but not quantified.

These positive results are in contrast to MAPS/NORML's previous studies into vaporizers which found less encouraging results.

A 1996 MAPS study tested two simple vaporizer models, a commercially-available electric hotplate vaporizer and a homemade hot air gun vaporizer, against water pipes and filtered and unfiltered cannabis cigarettes (joints). The smoke produced by each was analyzed for solid particulates (tars) and three major cannabinoids. The various ingestion methods were then rated based on their cannabinoid-to-tar ratio. The two tested vaporizers performed up to 25% better than unfiltered cannabis cigarettes (second cleanest) in terms of tar delivery. Both vaporizers produced more than ten times more tars than cannabinoids, though the NIDA-supplied marijuana used had a relatively low THC potency of 2.3%; the authors noted that using higher-quality marijuana or hash oil would have improved the cannabinoid/tar ratio. The same study found that water pipes (bongs) and filtered cigarettes performed 30% worse than regular, unfiltered joints. The reason was that waterpipes and filters filter out psychoactive THC with the tars, thereby requiring users to smoke more to reach their desired effect.

Vaporizers do not completely eliminate respiratory irritation. A large puff of potent, vaporized cannabis will often cause severe coughing. Vaporization systems that utilize water and/or ice for cooling and moisture conditioning by running the vapor through a water pipe or "vaporization water tool" with ice attempt to address the temperature and moisture factor of the delivered vapor to enable larger inhalations without the respiratory irritation that still results from dry-vapor delivery.