What is THC? – A scientific update

A scientific summary of what we know about THC so far

By Fran Cà

A simplified summary of THC

For the full and scientific summary, scroll down.

THC (Delta-9-tetrahydrocannabinol) is by far the most abundant cannabinoid found in the cannabis plant and is mostly responsible for cannabis’ psychoactive effects. THC was the first cannabinoid to be isolated and synthesized, back in the late 1960s.

How THC affects our cannabinoid receptors

THC is very good at binding to your body’s cannabinoid receptors (CB-Rs), which are found in your brain, nervous system and immune system. These receptors are part of your body’s endocannabinoid system (ECS) which regulates many important bodily functions and helps keep your body in balance. THC has the innate ability to mimic certain cannabinoids that your body can make for itself, called endocannabinoids, in particular Anandamide (AEA) and 2-Arachidonoylglycerol (2-AG). The difference between the three is that THC stays active a lot longer and is a lot stronger than AEA and 2-AG, giving you an extra boost of euphoria and energy when you consume high amounts of THC.

Medicinal benefits of THC

Not only is THC the main cannabinoid that is responsible for the psychoactive effects of cannabis, it is also beneficial for us humans in other ways, namely;

– THC helps to lessen the sensation of pain (analgesic).

– THC can relieve itching (antipruritic).

– THC helps to relax muscles.

– THC can help prevent spasms and convulsions (antispasmodic).

– THC can relax the bronchial muscles in your lungs, helping you to get more air into the lungs and make breathing easier (bronchodilator).

– THC helps to protect your nerve cells against damage and keeps them active longer (neuroprotective).

– THC protects all your body’s cells against “oxidation”, where oxygen or free radicals slowly damage the cells (antioxidant).

– THC helps to prevent and relieve inflammation throughout the body

– Some scientists even believe that THC can help to prevent Alzheimer disease and stomach ulcers.

A scientific summary of THC

THC (Delta-9-tetrahydrocannabinol or Δ9-THC) is the main cannabinoid present in the cannabis plant, representing over 40% of its chemical composition (depending on the variety). This compound is produced from a precursor called THC-acid (THCA). The maximum percentage of THC contained in a strain can be highly variable (from 18.0% to 30.0%) with an average concentration of 16.8% in flowers.

How THC affects our cannabinoid receptors

The first time this cannabinoid was isolated and synthesized was in late 1960s, and found to be the primary psychoactive component of cannabis.
Thirty years later, it was discovered that THC has a high binding-affinity to specific membrane receptors in the human brain called cannabinoid receptors (CB-Rs)*. Where as CB1-R is mainly found in the central nervous system (CNS), and CB2-R in the immune system.
Under normal physiological circumstances, CB-Rs are activated by “human” cannabinoids defined as endocannabinoids*. In this specific case, THC mimics the effect of two endocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG). However, unlike these “human” compounds, THC does not rapidly degrade and activates all CB-receptors throughout the brain.

*CB-Rs, endocannabinoids, and the enzymes involved in the production and degradation of these compounds together form the endocannabinoid system (ECS).

Medicinal benefits of THC

THC is not only responsible for the psychoactive effects of cannabis (such as euphoria and heightened sensory perception) but it also exerts analgesic (1), muscle-relaxant and antispasmodic (2) activities.
The cannabinoid THC also acts as a bronchodilator (3), neuroprotective (4), antioxidant (5), antipruritic (6) in cholestatic jaundice (7) and anti-inflammatory agent. Evidence has shown that THC has an anti-inflammatory power 20 times that of aspirin and twice that of cortisol.
It is also involved in the inhibition of two enzymes (COX-1 and COX-2) producing prostaglandins (8), which are involved in inflammation processes such as pain and fever.
Likewise, THC has demonstrated to be beneficial towards the reduction of Alzheimer disease and duodenal ulcers (9) .

The Entourage Effect of THC and other cannabinoids and terpenes

THC’s pharmacological activity is the result of a co-action (entourage effect) with other cannabinoids such as CBD and substances known as terpenes. CBD decreases the psychoactivity and other side-effects of THC, while enhancing its benefits.
Terpenes, in particular limonene, myrcene, pinene, linalool, and caryophyllene, enhance its effects and make it more efficient and more easily absorbed by our bodies.


(1) Analgesic: The ability to diminish the sensation of pain.

(2) Antispasmodic: The ability to relieve or prevent spasms and convulsions.

(3) Bronchodilator: A substance which causes relaxation of bronchial muscles, facilitating the entry of air into the lungs.

(4) Neuroprotective: The ability to protect nerve cells against damage, degeneration, or impairment of function

(5) Antioxidant: A substance which slows down the damage of living cells through “oxidation” by oxygen, peroxides, or free radicals.

(6) Antipruritic: The ability to relieve itching.

(7) Cholestatic jaundice: A yellowing of the skin caused by thickening of bile, obstruction of hepatic ducts, or changes in liver cell function.

(8) Prostaglandins: Any of a group of cyclic fatty acid compounds with varying hormone-like effects, notably the promotion of uterine contractions.

(9) Duodenal ulcers: Duodenal ulcers are a common cause of abdominal pain.


Elzinga et al. Nat Prod Chem Res 2015, 3:4

Lafaye G, et al. Dialogues Clin Neurosci. 2017; 19(3): 309–16.

Ren Health. Medical cannabis – review of risks and benefits. Available at

Russo EB. Br J Pharmacol. 2011;163(7):1344-64

Russo E. Medicinal Cannabis Conference 2017. Phytocannabinoids-Cannabis-Terpinoids. Available at:

Post author
Fran Ca
Fran Cà is Coffeeshop Guru's in-house medicinal cannabis expert and all-around science nerd. She scours the latest research papers with pin-point precision to keep you up-to-date on the most recent developments and thrilling discoveries surrounding the awesome power of cannabis.
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