Key takeaways.

  • What is THC?

    THC is the major cannabinoid found in cannabis and is responsible for cannabis' intoxicating effects.

  • What are some of the medicinal uses of THC?

    THC is used recreationally and medicinally. It has therapeutic uses in insomnia, epilepsy, Parkinson's disease, fibromyalgia, depression, and more.

  • How does THC work?

    THC binds to cannabinoid receptors in the human brain, causing a cascade of events in what's known as the human endocannabinoid system. Basically, THC uses the endocannabnioid system as a vehicle to move THC through your body and cause its effects.

  • What does it feel like to take THC?

    Users report feeling euphoric, heightened senses, dizziness, increased hunger and thirst, divergent thinking (abstract forms of thinking), and the giggles.

  • What are some of the different ways to use THC?

    THC can be smoked in cannabis buds, eaten in edibles, consumed as a tincture, it can be vaped, and it can be used as a topical treatment.

It was not so long ago that cannabis’ seat was among other illicit substances like cocaine, heroin and amphetamines. As the legalization movement sweeps across the planet, public, scientific and medical opinion are slowly shifting. It has been a great task of the cannabis industry to correct decades of misinformation about cannabis, how it can be used and who is an appropriate candidate for this type of herbal medicine.

The cannabis movement has revolutionized the way that the human race uses THC and cannabis. Once upon a time, cannabis belonged only in a pipe for smoking or in an alcoholic tincture. The influence of modern technology on cannabis has lent itself to more refined extraction techniques and an abundance of new ways to ingest cannabis.

This crash course is designed for the novice cannabis user or the one who is still entertaining the thought of using cannabis medicinally or recreationally. It highlights the medicinal uses, the different forms of ingestion and some basic information about cannabis’ chemistry and its pharmacokinetics with the human body.

What is THC?

THC is the main psychoactive cannabinoid found in cannabis. Cannabis contains over 400 chemical entities, mainly comprising cannabinoids, terpenoids and flavonoids. As the only psychoactive and intoxicating cannabinoid in cannabis, THC has been the most sought after constituent of cannabis until most recently. As science continues to learn more about the plant and its therapeutic potential, more cannabinoids are being investigated such as CBD, CBN and CBG.

While recreational cannabis users enjoy THC’s intoxicating effects, medicinal users enjoy its many curative and restorative applications. Traditionally, it was used for insomnia, menstrual cramps, and melancholy. It has played a major role in Hindu, Rastafarian and South American cultural traditions as a holy sacrament.

Essentially, THC is responsible for the intoxicating feeling that cannabis users report. Feelings of euphoria, physical and emotional hypersensitivity and divergent thinking are all associated with THC intoxication. Though it’s likely that other compounds present in cannabis potentiate or contribute to this effect (like terpenes), THC is the main culprit.

Medicinal properties of THC - What is it used for?

Cannabis, THC, and their medicinal uses have a long and colorful history. The use of cannabis dates as far back as 6,000 years ago in ancient China, where it was probably used predominantly for its fibers. Cannabis was cited in Herodotus’ writings, describing its use as a vapor bath in ancient Greece. Pliny the Elder also wrote about cannabis, its effects and its medicinal uses for the Romans. 

Virtually every American apothecary stocked cannabis extracts (mainly in the form of tincture) on its shelves during the 19th and early 20th century. It was used most commonly in the treatment of female reproductive issues, to assist in childlabor, to decrease pain and melancholy and to induce sleep.

The Marihuana Tax Act that was introduced in 1937 put a halt to the sale of cannabis patents, and it was effectively dropped from the United States Pharmacopoeia. Subsequent to this, it was not typically used medicinally in the USA. Following the counterculture of the 1960s, the USA declared the War on Drugs, and this slowed down virtually all scientific enquiry into cannabis and its uses.

Modern science is just beginning to catch up on the knowledge of our ancestors. Since the legalization movement, an abundance of scientific enquiry into cannabis has taken place. It has revealed just how versatile cannabis is for the treatment of an entire plethora of ailments.

Cannabis, the endocannabinoid system, and pharmacokinetics

Before understanding the medicinal properties of THC, it is important to understand how it moves through the human body.

When THC is ingested, it directly affects the human endocannabinoid system. The understanding of the human endocannabinoid system is still infantile. In fact, the discovery of the human endocannabinoid system can be attributed to THC research specifically. It was discovered in Raphael Mechoulam’s laboratory in Israel in the 1960s while studying, isolating and researching THC.

The endocannabinoid system is a non-localized signalling system made up of endogenous cannabinoids and cannabinoid receptors. Its main function is to maintain homeostasis (balance) between the body’s major systems including the nervous system, the endocrine system, and the immune system. It uses backwards communication to down-regulate or stimulate a certain system of the body.

The endocannabinoid system as a whole can be thought of as the other half of the nervous system. While neurotransmitters initiate, excite and inhibit nervous responses, the endocannabinoid system is essentially the “off switch” for these aspects of nervous function.  This is one of the major ways that the endocannabinoid system contributes to overall balance and homeostasis.

The cannabinoid, THC, very closely resembles an endogenous (or internal) cannabinoid of the human body called anandamide. Anandamide is implicated in vital human physiological and cognitive functions such as memory, higher intellectual function, learning, mood, and motor function. When THC enters the body, it interacts with the body and brain’s cannabinoid receptors, mimicking the action of anandamide and indirectly affecting other human cannabinoid receptors.

How THC is used medicinally in the modern world

Given THC’s affinity for the endocannabinoid system — which has a number of functions in varying body systems — its medicinal applications are enormous.

The most common medicinal application of THC in the USA is for the treatment of chronic pain, especially if its origins are in Parkinson’s Disease or multiple sclerosis (MS).

However, there are multiple ways to use THC medicinally. According to research, THC may have the following actions:

And overall, there is evidence to suggest that THC may be an effective alternative or complementary medicine for the following conditions:

Interestingly, cannabis researcher Dr. Ethan Russo suggests that the main application of medicinal cannabis is in a condition he has coined clinical endocannabinoid deficiency (CECD). He suggests that at the root of many treatment resistant conditions (such as Crohn’s disease, fibromyalgia and migraines) is a deficiency of the endocannabinoid system. He suggests cannabis as a treatment for this underlying cause.

Recreational use of THC

Cannabis remains the most commonly used illicit substance in the world. All over the world, a recreational cannabis culture exists. This is obviously due to THC, the intoxicating aspect of cannabis. But aside from just being intoxicating, it has forever been reported to induce laughter. In fact, it’s somewhat a mystery that modern medicine hasn’t harnessed this recreational “side effect” of cannabis use as a therapeutic action in and of itself!

Cannabis is typically used recreationally among friends. The most common administration route for recreational use is smoking, although there are now an abundance of ways to consume THC. 

The more generalized “symptoms” of THC intoxication include

  • Euphoria
  • Divergent thinking
  • Blurred vision
  • Dizziness
  • Enormous appetite
  • Spontaneous and uncontrollable laughter
  • Paranoia and anxiety
  • Red eyes
  • Decreased reaction time

However, not everybody who smokes or uses THC necessarily experiences all of these things. The experience itself is extremely subjective, and users often experience any number of a whole spectrum of effects.

The most interesting observation is how different people experience cannabis socially. For example, some people report becoming more introverted and entertained by their inner worlds. Others report extroversion and a desire to talk and be social. Unlike alcohol, cannabis’ effects do not always have a social context and are not always easy to predict.

Cannabis may be the perfect precursor for dancing for one person, and for another it may be the perfect precursor to a movie in bed. The different ways that cannabis affects different people contributes to the mystery and controversy surrounding this plant. There is no real way to accurately “predict” the effects of cannabis on any given person or personality type.

The different ways to use cannabis: Smoking, edibles and vaporizing

Once upon a time, cannabis belonged exclusively in the end of a smoking device like a pipe. It was sometimes steeped in alcohol to prepare a cannabis tincture. But outside of these two things, there was almost no other way to consume cannabis.

The modern world of technology and extraction has made it possible to create almost anything with cannabis. It can be eaten, drank, smoked, taken as a supplement, used topically or applied through a transdermal patch. 


Despite the new, wondrous ways to consume cannabis, smoking remains the most common administration route. The dried herb is mulled or ground and then, using a rolling paper, is fashioned into a cannabis cigarette. 

In general, this method of administration retains the more classical aspects of the herb. It retains taste, smell and is effective basically immediately.

For recreational users, this is generally preferred as a joint can be shared among friends in a circle.


Thanks to the fact that THC is fat-soluble, it can also be used in baking. The buds are slow-cooked in butter creating a cannabis butter. That same butter is then used to make cookies, brownies, cakes or any other baked goods. THC can also be dissolved in coconut oil and then used to make gummies.

Edible THC manufacturers also sometimes employ sophisticated extraction techniques to extract THC from the rest of the plant material. The pure, crude extract is then used to manufacture other THC-containing edibles such as candies, THC beverages, chocolate, etc.

Edibles typically take up to 2 hours to take effect, depending on a person’s metabolism and sensitivity to THC. However, effects live much longer than if THC is inhaled, and effects can also be more intense. 

Edibles are sometimes preferred by medicinal users because of the long-lasting effects. It is also a better administration route for medicinal users whose problem resides in the stomach or gastrointestinal tract, as cannabinoids can be sent directly to the discomfort.


It has become a relatively new practice for cannabis users to vaporize THC. This practice arguably began with dabbing, which is a way to inhale a very potent THC extract. However, dabbing is done with something called a dabbing rig. It looks a lot like a bong or water pipe, except that nothing is combusted in the process of using it. Rather, the bowl is heated up with a blow torch, after which the THC extract is put inside to turn into a vapor. It can then be inhaled.

A vaporizer follows the same principles, except that there now exist high-tech devices that heat up the extract for the user. A immediately heats the extract to the desired temperature, after which it can be inhaled.

Dried cannabis herb (non-extracted) can also be vaporized. However, it requires another special device that can vaporize the floral material. One such example is the Volcano by Storz & Bickel.

Just as with smoking, vaporizing THC is effective immediately. Effects last up to 2 hours. For those who prefer inhalation but use cannabis medicinally, vaporizing is considered to be much more conducive to health than smoking.

THC’s basic chemistry

THC is the simplified name for Δ9- tetrahydrocannabinol. Its chemical formula is C21H30O2. It contains an unsaturated bond between the C9 and C10 in the common dibenzopyran ring numbering system. Its molecular weight is 314.5g/mol. 

There are four stereoisomers of THC, but only one exists naturally — the (—)trans isomer. The active isomer Δ8-THC, in which the unsaturated bond in the cyclohexene ring is located between C-8 and C-9, is found in much smaller amounts than Δ9-THC.

When Δ9-THC is consumed in its raw form, it is non-psychoactive. It undergoes a process of degeneration by heat and light in a process called decarboxylation. During this process, the carboxyl group is removed from the chemical formula. This typically happens during the drying of the plant material, and then again by combustion when it is smoked. For the purpose of making edibles or other cannabis extracts, the plant material is decarboxylated in the oven to produce the psychoactive form of Δ9-THC.

THC and safety

The 1930s US film, Reefer Madness, accurately represents the outdated attitude towards the safety profile of THC. It was said to cause “madness”, “hysteria”, “schizophrenia”, and ultimately lead a person to become stupid. Needless to say, modern science has negated many of these alleged side effects of THC.

Overall, THC has a fairly good safety profile for adults. There is growing concern over its effects on the developing brain, such as in adolescents and the fetal brain. There are concerns that neurotoxic substances like THC can inhibit the full and proper development of the human brain. However, this only relates to adolescents using cannabis and the fetal brain if pregnant mothers use cannabis (although cannabis use during pregnancy is not properly studied).

There are also some concerns over the potential for THC addiction. However, the mechanisms behind this are not fully understood, and it is an overwhelmingly understudied aspect of cannabis.

THC and other cannabinoids are processed in the liver by the Cytochrome P450 enzymatic pathway. There is little research to understand how THC interacts with other drugs using the same enzymatic pathway in the liver, but given the fact that it uses this pathway, it may interact with other drugs metabolized in the same way.

Finally, there has been a lot of media commentary about the potential of THC to cause schizophrenia. No scientific research until now has confirmed THC as a causative factor of schizophrenia. In individuals with schizophrenic tendencies, THC can exacerbate this and is therefore not recommended for use in individuals with psychotic disorders. There may be a correlation between THC use and schizophrenia, as schizophrenics are more likely to self-medicate with cannabis. However, there is no evidence to suggest that THC alone is a causative factor of schizophrenia.

Side effects of THC use

Side-effects of THC use are generally short lived and reversible by abstaining from use. Not all people experience all side effects. The most common side effects include:

  • Dry mouth
  • Red eyes
  • Impaired motor function
  • Increased appetite
  • Decreased libido (with chronic use)
  • Sleepiness
  • Anxiety or paranoia
  • Short term memory loss

Mental health dangers of THC use

As briefly discussed earlier, there is a common misconception that THC use puts somebody at greater risk of developing a psychotic disorder. There is currently no evidence to support this. Rather, correlations have been made between THC and schizophrenia and other psychotic disorders, to the effect of the “chicken and egg” story. That’s to say that those with a predisposition are more likely to self-medicate with cannabis, which may exacerbate the symptoms of the psychotic condition. Essentially, THC may trigger an already predisposed person to developing more pronounced symptoms of psychosis. This may be where the common theory comes from that cannabis can lead to greater chances of schizophrenia.

With that said, those who have a family history of schizophrenia or are predisposed to psychotic tendencies are typically not recommended to use THC. There are non-psychoactive cannabinoids which may be more appropriate such as CBD.

Otherwise, cannabis also does not seem to be linked to higher incidence of depression. It may be linked to a higher chance of developing Social Anxiety Disorder (SAD). 

For those with bipolar disorder, cannabis may also contribute to more pronounced symptoms.

Finally, heavy and regular cannabis users were found to be more likely to have suicidal thoughts than non-sers, but cannabis users are not more likely to commit suicide than nonusers.

Important things to take away

Cannabis and THC are extremely valuable medicinal tools, even if modern science hasn’t quite caught up to all of the anecdotal evidence. If used correctly, THC can markedly improve symptoms of conditions that are otherwise stubborn and resistant to treatment.

The most important things to take away are:

  • THC is the most abundant phytocannabinoid in the cannabis plant
  • Until the 1930s, cannabis was a staple medicine in apothecaries all over the USA, and before that, was used for thousands of years by virtually every civilization on the planet
  • Its most common use in the USA is in the treatment of chronic pain
  • THC is used both recreationally and medicinally
  • The most common administration routes of THC are smoking, edibles (including beverages) and vaporizing
  • Cannabis is being investigated for its therapeutic potential in the treatment of Parkinson’s, epilepsy, PTSD, Crohn’s disease, Alzheimer’s, fibromyalgia and other treatment resistant conditions
  • THC is typically not recommended for adolescents and is not typically recommended for use during pregnancy (although very little study exists as to why)
  • Caution should be taken by those who wish to use THC but are afflicted with bipolar disorder, schizophrenia, psychosis or other psychiatric conditions

The movement towards cannabis legalization is with the ultimate purpose of making a perfectly viable medicine accessible to everybody. Though THC may not be a suitable remedy for everybody, it has specific applications in which it has proved itself to be extremely effective, as we see in Alzheimer’s and Parkinson’s Disease. THC is considered to have quite a good safety profile, especially when compared with other pharmaceutical medications.

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