How much do you really know about THC, the psychoactive compound in marijuana key to the high we know and love?
THC is one of more than 110 cannabinoids in marijuana. THC acts on the body’s endocannabinoid system (ECS), and produces psychoactive effects by latching onto CB1 receptors in the ECS. Delta-9-tetrahydrocannabinol (THC) is the best-known type of THC, but a similar cannabinoid called delta-8-tetrahydrocannabinol (delta-8) also exists.
Curious to learn more about the history of THC, its chemistry, and all the ways on which it acts upon the body? Then you’ve come to the right place. Don’t worry, we won’t overwhelm you – here, the science is made easy!
What is the molecular structure of THC?
Believe it or not, THC has the same molecular structure as its non-psychoactive cousin cannabidiol (CBD) – C21H30O2, meaning each molecule contains 21 carbon, 30 hydrogen and two oxygen atoms. Delta-8 also has a molecular structure of C21H30O2.
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Physical Form of THC
THC is created by cannabis, and is mostly produced by the flowering parts of the female cannabis plant. Small levels of THC are also created by the leaves, while the stalks and stems make minimal amounts. Female cannabis plants produce decidedly more THC than male cannabis plants.
Chemistry of THC
Marijuana has a very complex pharmacology and contains a cocktail of cannabinoids, terpenes and flavonoids. The latter two are important, but it is the cannabinoids that make cannabis unique.
The most concentrated cannabinoids in cannabis are THC and CBD, but there are numerous other “secondary cannabinoids”, including cannabichromene CBC), cannabigerol (CBG), cannabinol (CBN) and cannabidivarin (CBDV). These compounds all influence the effects of marijuana, although scientists have barely scratched the surface with research on many of these.
Mechanism of Action
Interestingly, the body creates its own “THC-like” compound called anandamide, which is classified as an endocannabinoid – in a nutshell, a cannabinoid produced endogenously. Anandamide is referred to as the “bliss molecule”, has antidepressant and analgesic properties, and plays a part in the euphoric “runner’s high” that many experience after a vigorous period of exercise.
THC and anandamide act on the ECS quite similarly – THC is a partial agonist of CB1 receptors, whereas anandamide is a weak, but full agonist of these receptors. THC is much stronger than anandamide, hence why it can give you that psychoactive high, while anandamide cannot.
THC is also a partial agonist of the CB2 receptor, which has less to do with mental effects and more to do with immune system regulation. Research suggests that, as with the CB1 receptor, THC is a partial agonist of CB2, while anandamide is a weak but full agonist.
There’s another endocannabinoid in the mix, too, known as 2-Arachidonoylglycerol (2-AG), which is a full agonist of both the CB1 and CB2 receptors.
Scientists still have much to learn about the ECS, cannabinoid receptors, cannabinoids and endocannabinoids. Some have even mooted that the body may have a third cannabinoid receptor (currently known as the GPR-55 receptor). This would add yet another dynamic to our already patchy understanding of the ECS.
The body mostly metabolizes THC and delta-8 molecules into 11-OH-THC, which is then oxidized into 11-nor-9-carboxy-THC (THC-COOH). THC and delta-8 molecules – and all other cannabinoid molecules – are metabolized by liver enzymes in the cytochrome P450 system.
Origin of THC
People have been getting high for thousands of years, so there’s no doubt that cannabis has been generating THC and that our bodies have had endocannabinoid systems for millennia. But the documented history of THC is actually a much more recent development. Indeed, researchers only confirmed its existence in the mid 20th century!
THC (and CBD for that matter) were first extracted from cannabis in the 1940s, and THC was synthesised for the first time in the 1960s. Much of the breakthrough research in cannabinoid science has come from Israel, and the so-called “father of cannabis research” Dr Raphael Mechoulam – who says he has never smoked a joint!
Cannabis research has continued in Israel, and was supported for decades by US government funding to the tune of $100,000 a year. This is remarkable given cannabis has been banned and demonized in the US throughout this period.
The story goes that a US senator, whose son was smoking cannabis during the early 1960s, asked experts at the National Institute of Health (NIH) what the plant was doing to his son’s brain. The NIH had no research to draw upon, and hence made the call to Mechoulam, who had previously applied for NIH funding. What’s even more eye-raising is that the NIH rarely dishes out overseas grants. Sot they must have been very keen to learn about THC’s effects.
Mode of Use
THC can be enjoyed in a variety of ways, each of which produces a slightly different set of effects.
Inhalation: Smoking cannabis – in a joint, bong or pipe – is the most common way of taking THC. This approach, while harmful to the lungs, represents the most efficient way of getting THC into the bloodstream and into the brain, where it can administer those desirable psychoactive effects. Smoked cannabis typically starts to have an effect within a couple of minutes, and lasts for around three hours.
More recently, some health-conscious cannabis consumers have started vaporizing THC. As no smoke is created with vaping, the health risks are significantly reduced, and THC’s benefits still work in the same way. Cannabis flower, THC e-liquids and THC concentrates (crystals, wax, shatter) are all suitable for vaporizing.
Sublingual absorption: This involves taking THC under the tongue, where it is rapidly absorbed by the sublingual glands in the mouth. This is how cannabis tincture oils are typically enjoyed, and it’s a great mode of use if you want a fast-acting high without the negative effects of smoking or vaping. Sublingually absorbed THC takes a few minutes longer to kick in, and offers a similar length of experience to inhalation.
Oral: THC edibles and capsules are taken orally, and are absorbed by the stomach into the bloodstream. This process is much more gradual than the other two, and produces a quite difference high.
For starters, orally-taken THC doesn’t have an immediate effect – you’ll likely be waiting for 30 minutes to an hour. However, if you can wait that long, the advantage is that your high can last for up to six to eight hours.
As edibles and capsules kick in differently, even experienced smokers should be a little cautious when dosing with edibles, as the normal tolerance rules don’t apply. However, your tolerance to edibles will quickly build with regular consumption.
Topical: The benefits of THC topicals are strictly therapeutic, as you can’t get high from infused balms and creams. This is because the THC molecules do not permeate the skin and reach the bloodstream, and therefore cannot be transported to the brain.
However, the skin is teeming with CB1 and CB2 receptors, which THC can work with to provide localized relief from pain and inflammation. THC may also have antibiotic properties and anti-aging effects.
Other Names for THC
Officially, THC is known as delta-9-tetrahydrocannabinol and the cannabis plants as Cannabis Sativa and Cannabis Indica. But there’s a good chance you’ll know cannabis by some other names – and to be sure, there are hundreds!
Here are just a few: marijuana, ganja, hashish, pot, Mary Jane, bhang, the devil’s lettuce, herb and wacky backy.
Control Status of THC
THC (and all other cannabinoids) are kept in the most restrictive Schedule 1 classification of the federal government’s Controlled Substances Act. Officially, cannabis is deemed to have no medical use.
However, hemp – which is technically a strain of cannabis – is legal thanks to the Farm Bill. The wording states that hemp strains with up to 0.3% THC are legal. Of course, it’s not possible to get stoned off such a small amount of THC, especially when it’s being countered by the likes of CBD.
Some states have taken matters into their own hands and legalized cannabis for recreational or medicinal uses. As of September 2020, cannabis is recreationally legal in California, Colorado, Illinois, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont, Washington and Washington DC.
Medicinal uses for THC
THC has several touted medicinal uses, but many of these are still speculative. However, cannabis solutions containing THC have been approved in some parts of the world for rare and treatment-resistant epilepsies, including Dravet’s syndrome.
Researchers are optimistic that THC may be effective for post-traumatic stress disorder (PTSD), by helping to alleviate flashbacks and returning thoughts of traumatic events. And the early research is encouraging.
Some cannabis researchers are exploring the potential consequences of a dysfunctional endocannabinoid system, and have raised the concept of ‘Clinical Endocannabinoid Deficiency’. They argue that a dysfunctional ECS may be the underlying cause of fibromyalgia and migraines. Both are conditions that modern medicine has currently got few good answers for. If a malfunctioning ECS is the problem, it’s feasible that cannabis treatments involving THC could be an effective solution.