The method you use to consume medical cannabis influences where and how quickly THC and CBD are absorbed into your body. Cannabinoids are absorbed much more rapidly through the lungs when cannabis is smoked or vapourized than the absorption that occurs in the intestines when cannabis oil or softgels are ingested.
infographic comparing onset time between inhaled and ingested cannabis using 1 inhalation or 2.5mg of THC and equal amount of CBD. Onset is second to minutes when inhaled and 30 minutes to 2 hours when ingested.
When inhaled, the active ingredients of cannabis are absorbed almost immediately into your bloodstream through the lungs. Peak brain concentrations, coinciding with the effects you feel in your body and your mind, occur within seconds to minutes and the effects can last up to 6 hours.*
When we inhale, air—or cannabis smoke or vapour— it enters through the trachea and passes through the left and right bronchi. These divide within the lungs, like branches on a tree, into many bronchioles. At the end of each bronchiole are tiny air sacs, known as alveoli, that look like a cluster of grapes. The alveoli—of which there are 300 million in our lungs—expand like balloons and fill with air when your chest expands. The walls of the alveolus allow the exchange of gases between your breath on the inside (oxygen) and capillaries that wrap around the outside of each alveolus (carbon dioxide). The carbon dioxide is then exhaled through the trachea, nose, and mouth, while the oxygen-saturated blood in the capillaries courses through and nourishes the body. Cannabinoids in the smoke or vapour are also absorbed into the blood in the capillaries.
The absorption of cannabinoids—based on subjective experience and concentrations in the blood— appears to be similar whether cannabis is smoked or vapourized.
Given the slower onset and increased duration of effects compared to inhalation, it is important to start low and go slow. For dosing information, always follow the instructions provided with your product or talk to your healthcare provider.
Whether consuming cannabis oil with a dosing syringe, a spray, or using softgels, cannabis oil needs to be swallowed. Although the compounds can be absorbed in small amounts through the upper digestive tract, the bulk of the work is done beyond the stomach.
When you begin to feel the effects and how long they last may depend on whether your stomach is empty or full when you ingest cannabis. Taking cannabis oil or softgels with a fatty meal may increase the effects you experience.
*Some effects could last as long as 24 hours.