There are four main methods of ingesting marijuana: inhalation, oral, sublingual, and topical. Each method has unique characteristics that make it more or less appropriate for some consumers. Below is an overview of the various methods of ingestion and their risks and benefits.
Inhalation is the fastest method of delivery to the consumer. Most consumers prefer using marijuana this way. When a consumer inhales marijuana, the majority of cannabinoids enter the body through the lungs where they are passed along directly into the consumer’s blood stream. The effect is almost instantaneous. For some people who use marijuana medicinally, this makes inhalation is very effective--similar to the use of an inhaler for an asthma attack. In a 2007 study in the Journal of Chemistry and Biodiversity, subjects who consumed cannabis via inhalation reported feeling the effects of the medication within minutes, with peak effects around the hour mark and total duration of effects around two hours. Another benefit to inhalation is the ability to easily titrate one’s dose, making overconsumption less likely. However, it is important to note that there can be significant variation in these times due to factors, such as cannabinoid content, depth and length of inhalation (a.k.a. smoking style), and previous marijuana exposure (tolerance).
There are two ways to inhale marijuana, smoking and vaporizing. Smoking marijuana involves burning the flowers and inhaling the active components of the plant that are released. Vaporization acts in the same way, but the plant is not burned, rather it is heated to a temperature at which the active ingredients in the plant are released as vapor that is inhaled by the consumer. In fact, research done in 2004 in the Journal of Cannabis Therapeutics on vaporization via the Volcano vaporizer shows vaporization to be the most efficient way to administer cannabinoids via inhalation. Vaporization is a healthier alternative to smoking because it eliminates the irritation of the throat and lungs from that comes from exposure to high heat and burned organic matter. However, purported hazards of smoking marijuana have not been proven in the scientific literature. In a 2012 article published in the Journal of the American Medical Association, the authors studied over 5000 participants over 20 years, and found that “occasional and low cumulative marijuana use was not associated with adverse effects on pulmonary function.”
While vaporization is a good alternative to smoking, there are some issues with the new wave of oil based vaporizers. These new vaporizers have revolutionized the way that many people consume marijuana. However, they have not been tested for safety or efficacy over time in large samples. The vast majority of these devices utilize oils, which are concentrated forms of cannabis. While flowers can contain 5-20% THC, the concentrated oils contain up to 80% THC. This might be too strong for a novice consumer. Furthermore, ingredients used in the process of extracting oils have not been safety tested and there is the risk that there are residues from these ingredients in the final product. However, emerging applications of well-established clean extraction technologies, such as supercritical CO2 extraction, are being applied by those in the marijuana industry with some success. Overall, more research and testing of these products is needed.
Marijuana can also be ingested orally. This can be in the form of edibles, tinctures, capsules or oils. The onset for oral ingestion is slower and the effects are stronger and last longer than with inhalation. People who consume marijuana orally usually report feeling the effects within thirty minutes to one hour or longer, with peak effects around the two hour mark and total duration of effects ranging as long as six hours. This is because, during the process of digestion, the cannabinoids undergo a chemical transformation that makes them stronger. Also, when ingesting orally, none of the product is lost by sticking to the pipe or rolling paper. People using marijuana medicinally for long lasting chronic pain often prefer oral ingestion because it lasts longer and they don’t have to consume as often. However, marijuana ingested orally is difficult to properly titrate dosage due to the increased time of effect onset.
Marijuana can also enter the blood stream when placed under the tongue and held in the mouth; within the mouth there are a large number of blood vessels which can absorb cannabinoids. Common examples of these type of products include dissolvable strips, sublingual sprays, or medicated lozenges or tinctures. Sativex, the one clinically approved, cannabinoid medication that includes the entire spectrum of natural cannabinoids, is delivered as a sublingual spray. The time of onset for this method of consumption is similar to those seen in general oral consumption, however, some studies have reported an earlier onset.
A final way to consume marijuana is through topical applications. These come in the form of lotions, salves, bath salts and oils that are applied to the skin. The skin has a relatively complex absorption process that is based on a chemical’s ability to dissolve in H20. The cannabinoids penetrate the skin and work to reduce pain and inflammation. This method is very popular with older consumers because it works well on localized pain (like from arthritis) and is non-psychoactive. While not widely studied, there is research that shows that topical application of cannabinoids has an onset of action within minutes locally (i.e. creams and balms applied to a joint), with duration of these effects lasting one to two hours. Individuals who used patches reported onset of action within two hours and duration of effect lasting upwards of two days due to the time released nature of this method of administration. Additionally, the topical application of marijuana does not allow a significant amount of cannabinoids to reach the brain and therefore is unlikely to cause any intoxication.