Even though the perceived effects of inhaled and ingested cannabis can feel so different from one another, it is how the body assimilates and incorporates THC and other cannabinoids found in cannabis that makes for the stark differences between inhaling and ingesting.
There is no psychoactive THC found naturally in cannabis plants. What is actually found in the plant is tetrahydrocannabinolic acid (THCA), which has no psychoactive properties. THCA contains a carboxyl molecule which, when removed by a process called decarboxylation, gives cannabis its famed psychotropic properties.
With temperatures in excess of 350 degrees Fahrenheit, the elevated heat from smoking or vaping will instantly decarboxylate the THCA converting it into Delta-9-THC, the famously celebrated psychoactive cannabinoid of cannabis. When inhaled, the Delta-9-THC is immediately absorbed by the lungs flowing directly into the bloodstream and crossing the blood-brain barrier. The psychoactive effects occur within minutes so you can easily titrate and quickly moderate your intake maintaining levels you are comfortable with.
The decarboxylation of THCA to produce Delta-9-THC can also take place at lower temperatures such as those used for baking. The conversion is not instantaneous, and thus it requires 15 to 45 minutes depending on the temperature. In addition to producing Delta-9-THC for use in edibles, one of the advantages of heating at a lower temperature is the terpenes, which are responsible for the aroma of cannabis, are preserved.
Edibles are not absorbed through the respiratory system, but rather through the digestive system. Therein is the big difference, which accounts for why the potency and length of time of action is greater for cannabis that is eaten versus cannabis that is inhaled.
“The bottom line for edibles is you can always take more, but you can’t take less once you have taken them, so err on the side of caution, and wait at least two hours before consuming more.”
When Delta-9-THC goes through the digestive system rather than the respiratory system, it is metabolized in the liver and converted to 11-hydroxy-THC (11-OH-THC). This form of THC crosses the blood-brain barrier more quickly than Delta-9-THC and is considered to be more psychotropic, because it activates specific cannabinoid receptors in the brain more effectively than Delta-9-THC does. This is one of the reasons edibles are believed to be more likely to bring on feelings of anxiety, panic, paranoia and other negative psychotropic reactions.
Although this has been the accepted explanation for why edibles are more potent than smoking or vaping, not all researchers agree. Studies done at GW Pharmaceuticals, according to an article in The Atlantic, have found that the two compounds are basically equivalent and point to a far simpler explanation. The author refers to Dr. Ethan Russo and his skepticism for such an explanation. “Russo says the reason edibles affect people more strongly is simply because more THC—of any kind—gets into the body when pot is eaten. When a joint is smoked, only 10 to 30 percent of the THC is absorbed into the body, he says. A lot—quite literally—just goes up in smoke,” reads the article.
Whether the psychoactive effects of edibles derive from the potency of 11-OH-THC versus Delta-9-THC or the simple fact that you are going to get more psychoactive THC from ingesting than from inhaling, it still calls for more caution when edibles are consumed.
This is why knowing the amount of THC in edibles is critical. Eating someone’s homemade edibles with unknown potencies can be especially risky as beginners are advised to limit their intake of THC to between one and five milligrams. Once accustomed to the effects, dosages can be increased up to 10 milligrams. Most states that have legalized cannabis have set 10 milligrams as a single serving size although very experienced consumers can utilize considerably more with no ill effect.
Along with potency, the time for onset of the effects with edibles is critical with times of onset running from 30 minutes to two hours. Just because you have not felt anything in 60 minutes doesn’t mean you should take more. Overdosing is not going to kill you, but it is very uncomfortable, with some people going to emergency rooms with panic attacks and other distressful symptoms.
The bottom line for edibles is you can always take more, but you can’t take less once you have taken them, so err on the side of caution, and wait at least two hours before consuming more.