What Is THC? A Complete Guide to Tetrahydrocannabinol

By the JKF Team | Last updated July 7, 2026

THC is the compound most people associate with cannabis. It is what produces the high, the relaxation, the giggles, the munchies, and much of what makes cannabis the plant it is. But beyond those familiar effects, THC is a remarkably complex molecule with a specific mechanism of action inside your body. Whether you are a first-time visitor to our Bed-Stuy dispensary or a seasoned consumer looking to understand the science, this guide covers everything you need to know about THC.

What THC Actually Is

THC stands for tetrahydrocannabinol. Its full chemical name is delta-9-tetrahydrocannabinol, and it belongs to a class of compounds called cannabinoids. Cannabis plants produce over 100 different cannabinoids, but THC is the most abundant psychoactive one. It is the primary reason cannabis produces intoxicating effects.

Chemically, THC is a 21-carbon terpenophenolic compound. That means it shares structural features with both terpenes (the aromatic compounds that give cannabis its smell) and phenols. Its molecular formula is C21H30O2, and its structure includes a pentyl side chain that is critical to how it interacts with receptors in your brain and body.

THC was first isolated and synthesized by Israeli chemist Raphael Mechoulam in 1964. That discovery opened the door to decades of research into how cannabis affects the human body, eventually leading to the discovery of the endocannabinoid system.

The Endocannabinoid System: How THC Works in Your Body

THC does not just randomly float around your body creating effects. It works through a specific biological system called the endocannabinoid system (ECS). Understanding the ECS is essential to understanding why THC does what it does.

The endocannabinoid system exists in every human body, regardless of whether you have ever used cannabis. It was discovered in the early 1990s by researchers studying how THC interacts with the body. The ECS consists of three main components:

• Endocannabinoids: These are cannabinoid-like molecules your body produces naturally. The two primary endocannabinoids are anandamide (sometimes called the "bliss molecule") and 2-AG (2-arachidonoylglycerol). They help regulate mood, appetite, sleep, pain, and immune function.
• Cannabinoid receptors: These are protein receptors found on the surface of cells throughout your body. The two main types are CB1 and CB2 receptors.
• Enzymes: These break down endocannabinoids after they have done their job. The two main enzymes are FAAH (which breaks down anandamide) and MAGL (which breaks down 2-AG).

CB1 and CB2 Receptors

CB1 receptors are concentrated in the brain and central nervous system. They are found in especially high densities in areas associated with memory, coordination, pleasure, and cognition, including the hippocampus, cerebral cortex, basal ganglia, and cerebellum. When THC binds to CB1 receptors, it produces the psychoactive effects associated with being high: euphoria, altered perception of time, heightened sensory experiences, and changes in short-term memory.

CB2 receptors are found primarily in the immune system and peripheral tissues, including the spleen, tonsils, and white blood cells. They play a role in regulating inflammation and immune response. THC has some affinity for CB2 receptors, though it binds more strongly to CB1.

THC works by mimicking your body's own endocannabinoids. Its molecular shape is similar enough to anandamide that it can bind to the same CB1 receptors, activating them and triggering the downstream effects you experience as a cannabis high. This is also why THC can affect appetite, pain perception, and mood: it is activating the same receptors that your body's own regulatory molecules use.

Different Forms of THC

When people say "THC," they usually mean delta-9-THC. But there are actually several variants of tetrahydrocannabinol, each with different properties. Understanding these differences matters when you are reading cannabis labels at the dispensary.

Delta-9-THC

This is the primary psychoactive cannabinoid in cannabis. When a product label shows a THC percentage or milligram count, it is referring to delta-9-THC. It is produced naturally by the cannabis plant in significant quantities and is responsible for the classic cannabis high. All lab-tested products at licensed New York dispensaries report delta-9-THC content.

THCA (Tetrahydrocannabinolic Acid)

THCA is the raw, acidic precursor to THC found in living and freshly harvested cannabis plants. It is non-psychoactive in its natural form. When you apply heat to cannabis (by smoking, vaping, or baking it), THCA undergoes a chemical process called decarboxylation, converting it into active delta-9-THC. This is why eating raw cannabis flower will not get you high. On lab reports, you will often see both THCA and THC listed separately. The total THC is calculated using the formula: Total THC = (THCA x 0.877) + delta-9-THC.

Delta-8-THC

Delta-8-THC is a minor cannabinoid with a slightly different molecular structure than delta-9. The only difference is the position of one chemical bond. Delta-8 produces psychoactive effects, but they are generally reported as milder and less anxiety-inducing than delta-9. Most delta-8 products on the market are synthetically converted from CBD rather than extracted directly from cannabis, which puts them in a complicated regulatory space. New York's regulated market focuses on naturally occurring delta-9-THC.

THC-V (Tetrahydrocannabivarin)

THC-V is a minor cannabinoid found in small amounts in certain cannabis strains, particularly those originating from African landrace genetics. It has a shorter molecular side chain than delta-9-THC. At low doses, THC-V may actually block CB1 receptors rather than activate them, potentially suppressing appetite rather than stimulating it. At higher doses, it may produce a shorter, more energetic high. THC-V is relatively rare and is not present in most products, but it appears in some specialty strains and formulations.

How THC Potency Is Measured

Understanding how potency works is fundamental to choosing the right product and dosing correctly. THC potency is measured differently depending on the product type.

Flower: Percentage by Weight

For cannabis flower, potency is expressed as a percentage of the total weight. A strain labeled at 20% THC means that for every gram of flower, approximately 200 milligrams is THC. Most flower sold at Brooklyn dispensaries ranges from about 15% to 35% total THC. Higher percentages do not always mean a better experience; the terpene profile and the full spectrum of cannabinoids also shape the effects.

Edibles: Milligrams per Serving

For edibles, potency is measured in milligrams (mg) of THC per serving and per package. In New York's regulated market, products are clearly labeled with both values. A standard dose for someone with moderate experience is around 5 to 10 mg. First-time users should start with 2.5 mg or less and wait at least two hours before taking more.

Concentrates: Percentage by Weight

Concentrates like wax, shatter, live resin, and rosin are measured the same way as flower, by percentage. However, concentrates typically range from 60% to 95% THC, making them significantly more potent than flower. They are best suited for experienced consumers.

Tinctures: Milligrams per Milliliter

Tinctures express potency in milligrams of THC per milliliter (mg/mL) and per dropper. A tincture bottle might contain 300 mg of THC total, with each dropper delivering 10 mg. This format makes precise dosing straightforward.

Onset Times by Consumption Method

One of the most important things to understand about THC is that how you consume it dramatically affects how quickly you feel the effects, how intense they are, and how long they last. Here is a breakdown by method:

Smoking and Vaping (Inhalation)

When you inhale cannabis smoke or vapor, THC passes through your lungs directly into your bloodstream. Effects begin within 1 to 5 minutes and typically peak within 15 to 30 minutes. The total duration is usually 1 to 3 hours. This is the fastest onset method and allows for easy dose control because you can take a single puff and wait to assess the effects before taking another.

Edibles (Oral Ingestion)

When you eat a cannabis edible, THC passes through your digestive system and is processed by your liver before entering the bloodstream. The liver converts delta-9-THC into 11-hydroxy-THC, which is actually more potent and longer-lasting than the original compound. This is why edibles can feel significantly stronger than smoking the same amount of THC. Onset takes 30 minutes to 2 hours, with effects lasting 4 to 8 hours or more. The delayed onset is the number one reason people accidentally overconsume edibles. Always start low and wait. For more on safe edible consumption, see our edibles guide.

Tinctures (Sublingual)

Sublingual tinctures are placed under the tongue, where THC absorbs through the mucous membranes directly into the bloodstream. This bypasses the digestive system and liver, producing faster effects than edibles. Onset is typically 15 to 45 minutes, with effects lasting 2 to 6 hours. If you swallow the tincture instead of holding it under your tongue, it will be processed like an edible with a longer onset.

Topicals (Transdermal)

Cannabis topicals, including creams, balms, and patches, are applied directly to the skin. Standard topicals do not produce psychoactive effects because THC does not penetrate deep enough to reach the bloodstream in significant quantities. They are used for localized relief. Transdermal patches, however, are designed to deliver THC through the skin and into the bloodstream, which can produce systemic effects with an onset of about 15 to 45 minutes.

THC and the Entourage Effect

THC does not work in isolation. Cannabis contains dozens of cannabinoids (including CBD, CBN, CBG, and others) plus hundreds of terpenes and flavonoids. Research suggests that these compounds work together synergistically in what is known as the entourage effect.

The entourage effect theory proposes that the full spectrum of cannabis compounds produces different and potentially more beneficial effects than any single compound alone. For example, CBD may moderate some of the anxiety or paranoia that high doses of THC can cause. Certain terpenes like myrcene may enhance THC's sedating qualities, while limonene may contribute uplifting effects.

This is one reason why the THC percentage alone does not tell you everything about how a product will make you feel. Two strains with identical THC percentages can produce very different experiences based on their terpene and cannabinoid profiles.

THC in New York's Legal Market

In New York, all cannabis products sold at licensed dispensaries are lab-tested for THC content. This testing is mandated by the Office of Cannabis Management and performed by independent, licensed laboratories. When you purchase flower, edibles, concentrates, or tinctures at Jungle Kingdom Flower in Bed-Stuy or East Williamsburg, the THC content printed on the label has been verified through laboratory analysis.

This is a critical distinction from unlicensed sources, where THC claims are unverified and products are untested. Licensed products give you the information you need to dose safely and consistently.

Frequently Asked Questions