You’re at a party and a joint is being passed around. The room is filled with smoke and you start to wonder, will I get a contact high from weed? Is a contact high even real?
A contact high—also known as a secondhand high—is the idea that secondhand exposure to cannabis smoke can get a person stoned or even leave them with THC in their system. For nonsmokers, this can lead to worries: Can you fail a drug test from a contact high? Can you wind up accidentally stoned?
These are reasonable questions to ask, and fortunately, we have a pretty good idea of how a contact high works.
THC in the air
When cannabis smoke or vapor is inhaled, cannabinoids like THC are absorbed into the lungs and enter the bloodstream. But how much THC do we actually absorb? Well, that depends.
Researchers from The British Journal of Anesthesia in 1999 reported, “Approximately 50% of the THC and other cannabinoids present in a cannabis cigarette enter the mainstream smoke and are inhaled. The amount absorbed through the lungs depends on smoking style. In experienced smokers, who inhaled deeply and hold the smoke in the lungs for some seconds before exhaling, virtually all of the cannabinoids present in the mainstream smoke enter the bloodstream.”
You may be thinking that 50% may not sound like much, but a more recent study suggests it could be even less. A 2005 study titled “Pharmacokinetics of cannabinoids” found that, “the variability of THC in plant material (0.3% to 30%) leads to variability in tissue THC levels from smoking, which is, in itself, a highly individual process. THC bioavailability averages 30%.”
In other words, studies show that inhaled cannabis smoke does not allow for 100% bioavailability, and while length and duration of the inhale may possibly play a role in absorption, exhaled cannabis smoke might still have THC present.
So we know secondhand cannabis smoke can maintain cannabinoids, but is it enough to get someone stoned? Or even affect a drug test?
Read full article here: https://www.leafly.com/news/cannabis-101/what-is-a-contact-high