One of the major arguments against medical marijuana is the potential risks of inhaling smoke, since smoking is the traditional methods of cannabis delivery. Research has shown that cannabis smoke does contain some [irritants and carcinogens](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1277837/# B47) similar to tobacco smoke. Other research, however, has also shown that the cannabinoids in marijuana provide some protection against damage from these chemicals - cannabis seems to boost the immune response and block enzyme action needed for carcinogenesis - and has failed to find a link between marijuana and lung cancer or long-term negative effects on lung capacity.
Smoking cannabis has, however, been linked to respiratory problems including increased coughing, wheezing, sputum production, and airway inflammation. Thus, patients may be reluctant to use this method despite evidence showing it is faster than ingestion for cannabinoid delivery.
Another cannabis delivery option is vaporization. In this method, the cannabis is heated to a temperature lower than what occurs with combustion (combustion occurs at about 230°C). The lower temperature (185°C) releases the cannabinoids, and not the toxins, into a mist or vapor that is inhaled. The amount of cannabinoid delivered is similar to that of smoking, but has fewer respiratory symptoms and problems.
Tetrahydrocannabinol (THC) is one of the most abundant cannabinoids in cannabis and is associated with the marijuana high. THC can help treat pain, nausea, vomiting, and appetite loss. In a study that compared vaporization and smoking, researchers found that THC levels were between 36 percent and 61 percent for vaporization, which is similar to the levels found with smoking cannabis. Furthermore, examination of the vapor found only trace amounts of the toxic chemicals found in smoke.
Each cannabinoid has a different evaporation temperature. THC evaporates at about 157°C, whereas cannabidiol (CBD) evaporates at temperatures between 160 and 180°C. CBD has been found effective in treating pain, nausea, vomiting, anxiety, and depression, as well as in reducing cancerous tumors. The trick with vaporization is to keep the temperature high enough to release the cannabinoids, but low enough to prevent combustion.
Current vaporizers work either through conduction or convection. In conduction, the cannabis is placed directly on a heating element, sometimes referred to as a nail, that has been heated with a flame. With convection, heat is indirect and is transferred through a gas or liquid to the cannabis. Both methods have some positives and negatives.
Vaporizers take either herb (leaves and flowers) or concentrate. Vapor from herbs contains between 5 percent and 20 percent THC and from concentrate about 60 percent. To create concentrate, cannabis is filtered through a solvent, ice water, or carbon dioxide to separate the THC from the plant matter. This concentrate is then placed in the vaporizer for use.
Patients should talk with their medical marijuana professional to see what types of vaporizers and what form of cannabis would be best for their needs. Each form a vaporization has benefits for patients depending on the type of condition they wish to alleviate.