science

Tetrahydrocannabinol

Tetrahydrocannabinol is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Tetrahydrocannabinol rather than just read about it. In short: Tetrahydrocannabinol (THC) is a cannabinoid found in cannabis. It is the principal psychoactive constituent of Cannabis and one of at least 113 total cannabinoids identified on the plant.

Key takeaways

Tetrahydrocannabinol belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tetrahydrocannabinol to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tetrahydrocannabinol from memory before moving on to harder problems.

Reference excerpt

Tetrahydrocannabinol (THC) is a cannabinoid found in cannabis. It is the principal psychoactive constituent of Cannabis and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) describes multiple isomers, the term THC usually refers to the delta-9-THC isomer with chemical name (−)-trans-Δ9-tetrahydrocannabinol. THC, also known pharmaceutically as dronabinol, is used medically to relieve chemotherapy-induced nausea and HIV/AIDS-related anorexia. Nabiximols, a botanical drug which contains THC, is used medically to treat symptoms of multiple sclerosis, including spasticity and neuropathic pain. THC acts as a partial agonist at CB1 and CB2 cannabinoid receptors. THC can be administered orally, inhaled, or transdermally, with bioavailability and onset varying by route, and is extensively metabolized in the liver to active and inactive metabolites before being excreted in feces and urine. Side effects include red eyes, dry mouth, drowsiness, memory impairment, anxiety, and, with chronic use, cannabinoid hyperemesis syndrome. While human overdose is rare, THC can interact with other drugs and has a complex pharmacokinetic profile. THC is classified variably under international and US law, with medical use approved in multiple countries. Research supports its effectiveness for spasticity and central pain in multiple sclerosis, though evidence for other neurological disorders is limited, and long-term high-dose exposure may carry uncertain toxicity risks.

Uses

Recreational

THC is widely used as a recreational drug, both by itself or with other cannabinoids like cannabidiol (CBD) or in the form of cannabis. It is the main psychoactive constituent in cannabis. The effects of THC include euphoria, appetite stimulation, sedation, cognitive and memory impairment, pain relief, anxiety, and reduced body temperature. THC can produce strong hallucinogenic effects, mystical experiences, and psychosis-like reactions at high doses in a subset of individuals. These hallucinogenic effects are distinct from but potentially just as strong as or even stronger than those of other hallucinogens like serotonergic psychedelics, dissociatives, and salvia. Besides the hallucinogenic effects, high doses of THC can also produce effects including anxiety, panic, paranoia, delusions, heavy sedation, and catalepsy. Strong THC exposures and associated hallucinogenic and aversive effects have been especially associated with cannabis edibles.

Medical

THC, referred to as dronabinol in the pharmaceutical context, is approved in the United States as a capsule or solution to relieve chemotherapy-induced nausea and vomiting and HIV/AIDS-induced anorexia. THC is an active ingredient in nabiximols (Sativex), a specific extract of Cannabis that was approved as a botanical drug in the United Kingdom in 2010 as a mouth spray for people with multiple sclerosis to alleviate neuropathic pain, spasticity, overactive bladder, and other symptoms. Nabiximols (as Sativex) is available as a prescription drug in Canada. In 2021, nabiximols was approved for medical use in Ukraine. THC is sometimes prescribed off-label to treat glaucoma, Crohn's disease, and post-traumatic stress disorder (PTSD).

Side effects Side effects of THC can include red eyes, dry mouth, drowsiness, short-term memory impairment, difficulty concentrating, ataxia, increased appetite, anxiety, paranoia, psychosis (i.e., hallucinations, delusions), decreased motivation, and time dilation, among others. Chronic usage of THC may result in cannabinoid hyperemesis syndrome (CHS), a condition characterized by cyclic nausea, vomiting, and abdominal pain that may persist for months to years after discontinuation.

Overdose The median lethal dose of THC in humans is not fully known as there is conflicting evidence. A 1972 study gave up to 90 mg/kg of THC to dogs and monkeys without any lethal effects. Some rats died within 72 hours after a dose of up to 36 mg/kg. A 2014 case study based on the toxicology reports and relative testimony in two separate cases gave the median lethal dose in humans at 30 mg/kg (2.1 grams THC for a person who weighs 70 kg; 154 lb; 11 stone), observing cardiovascular death in the one otherwise healthy subject of the two cases studied. A different 1972 study gave the median lethal dose for intravenous THC in mice and rats at 30–40 mg/kg. A 2020 fact sheet published by the US Drug Enforcement Administration stated that "no deaths from overdose of marijuana have been reported."

Interactions Formal drug–drug interaction studies with THC have not been conducted and are limited. The elimination half-life of the barbiturate pentobarbital has been found to increase by four hours when concomitantly administered with oral THC.

Pharmacology

Mechanism of action

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Tetrahydrocannabinol

Start with the simplest possible case. Write down what Tetrahydrocannabinol claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tetrahydrocannabinol before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tetrahydrocannabinol ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tetrahydrocannabinol

In research: Tetrahydrocannabinol appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tetrahydrocannabinol in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tetrahydrocannabinol is common in secondary-school and first-year university syllabi. It links to neighbouring topics Acetylcholinesterase inhibitors, Amorphous solids, Antiemetics, so understanding it makes those chapters shorter.
In everyday life: Look for Tetrahydrocannabinol outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Tetrahydrocannabinol in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tetrahydrocannabinol means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tetrahydrocannabinol out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tetrahydrocannabinol in simple terms?

Tetrahydrocannabinol (THC) is a cannabinoid found in cannabis. It is the principal psychoactive constituent of Cannabis and one of at least 113 total cannabinoids identified on the plant.

Why does Tetrahydrocannabinol matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tetrahydrocannabinol?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tetrahydrocannabinol.