Cannabinoids: What They Are and What Research Shows

Cannabinoids are the chemical compounds in cannabis that act on the body’s cannabinoid receptors: THC causes the high and CBD does not. The FDA has approved cannabinoid drugs only for certain seizure disorders, chemotherapy nausea and vomiting, and weight loss in people with AIDS, and it has approved no cannabis plant product for any condition.

When people talk about what medical marijuana does, they are mostly talking about cannabinoids, so this post explains what they are, how they act on the body and what research has and has not shown.

Without cannabinoids, cannabis would still be useful for seed oil and fiber, and its terpenes would still give it aroma, but the medical effects of terpenes are mostly unproven.

What Are Cannabinoids?

They’re chemical compounds.  The one you’re probably most familiar with is tetrahydrocannabinol or THC.

It is not the only one in the plant, and it is not the only one behind an FDA-approved drug.

Marijuana has more than 100 cannabinoids. You don’t need to know every one, but five come up often, and we cover them below.

What they do depends on how they act on the body’s own cannabinoid system, described next.

Scientists call it the endocannabinoid system.

What Is the Endocannabinoid System?

The system is named after the plant, but the body runs it on its own.

The body makes its own cannabinoids, which are similar to marijuana’s cannabinoids.  These human-produced cannabinoids are called endocannabinoids.  Marijuana’s cannabinoids are known as phytocannabinoids.

Endocannabinoids are part of the body’s endocannabinoid system.  The endocannabinoid system gets less attention than the nervous, cardiovascular or digestive systems.  But it plays a part in many of the body’s everyday processes.

It has three parts: the body’s own cannabinoids, the enzymes that make and break them down, and the receptors they bind to.

Cannabinoid receptors are found throughout the body. Endocannabinoids bind to these receptors and change how cells behave.

There are two main types of cannabinoid receptors:  CB1 and CB2.

CB1 receptors are found mainly in the brain and nervous system, and also in other organs. They bind the endocannabinoid anandamide as well as THC.

CB2 receptors are most abundant on immune cells such as B cells and natural killer cells, according to NCI. THC acts on both CB1 and CB2, while CBD does not activate them in the same way; a 2008 review describes it blocking other compounds at these receptors.

How Marijuana Acts on Your Endocannabinoid System

Researchers think the endocannabinoid system has a role in pain, movement, appetite, mood, memory, inflammation and the immune system.

Cannabis acts on that system, which is why researchers study it for pain, nausea and other symptoms. So far, only the FDA-approved drugs named at the top of this post have cleared that agency’s review.

The endocannabinoid system’s “lock-and-key” feature allows marijuana’s phytocannabinoids to bind with your body’s endocannabinoid receptors and change the behavior of your cells.  Some phytocannabinoids, such as THC, act by binding the same receptors as the body’s endocannabinoids.

For example, let’s say you’re feeling pain.  Your nerve cells send pain signals to your brain.

Cannabinoids bind to these receptors and can change pain signaling, but NIH reports that a 2018 review of 47 studies found evidence of only a small benefit for chronic pain.

Some medical researchers speculate that illnesses such as migraines, fibromyalgia and irritable bowel syndrome might be related to deficiencies in the endocannabinoid system.  This idea, called clinical endocannabinoid deficiency, was first proposed in 2001, and a 2016 review argued that newer research supports it, but it is still a theory, not a proven cause of these conditions or proof that marijuana treats them.

Treat any product claim built on this theory with caution.

Five Cannabinoids to Know

1. Tetrahydrocannabinol (THC)

THC is the main intoxicating cannabinoid. Drugs made from synthetic THC are FDA approved for chemotherapy nausea and AIDS-related weight loss, and THC has also been studied for

• Pain and inflammation
• Nausea
• Stress
• Sleep disorders

THC is also linked to side effects such as anxiety, distrust and panic, especially at high doses, NIDA notes. Many people believe another cannabinoid, CBD, offsets them.

2. Cannabidiol (CBD)

CBD does not cause a high. Its only FDA-approved use is for seizures in three rare conditions, a 2023 trial found it did not reduce THC’s side effects, and it has been studied, with limited or early results, for

• Pain and inflammation
• Epilepsy
• Psychotic illnesses
• Depression
• Diabetes
• Cancer

3. Cannabichromene (CBC)

CBC is one of the less studied cannabinoids. It has been studied in lab and animal research for inflammation, tumors and mood, with little research in people.

4. Cannabinol (CBN)

Claims made for this lesser-known cannabinoid, none established in people, include

• Appetite loss
• Certain bacterial infections
• Pain
• Asthma
• Glaucoma

5. Cannabigerol (CBG)

CBG does not cause a high; claims made for it, none established in people, include

• Pain
• Depression
• Certain bacterial and fungal infections
• Certain types of cancer

Cannabinoids and the Entourage Effect

Some patients look for the highest THC percentage they can find.   In fact, when we’re talking about marijuana concentrates, we’re really talking about THC concentrates.

None of this is a case against THC. It is the main active cannabinoid, but trials show only modest benefits for chronic pain, and THC can cause side effects such as anxiety and impaired driving.

That does not make the other cannabinoids irrelevant.  THC is only one of more than 100 cannabinoids in the plant, and researchers are still studying what the others do.

Some researchers think cannabinoids work better together, an idea called “the entourage effect.” A 2011 review laid out the theory, but it has not been proven in people.

Cannabinoids: Questions for Your Physician

Ask your physician which products fit your condition and your other medicines. In Florida, a licensed treatment center must lab test processed marijuana for potency and contaminants before it is dispensed, so the label shows its cannabinoid content.

Finally, if you have a Florida qualifying condition but don’t have a Florida medical marijuana card, schedule an appointment with us today.

Last updated October 18, 2026 by the Dr. Green Relief Editorial Team.

Sources

• FDA. FDA and Cannabis: Research and Drug Approval Process
• Pertwee RG. The diverse CB1 and CB2 receptor pharmacology of three plant cannabinoids. Br J Pharmacol. 2008 (PubMed)
• National Cancer Institute. Cannabis and Cannabinoids (PDQ), Health Professional Version
• NCCIH. Cannabis (Marijuana) and Cannabinoids: What You Need To Know
• Russo EB. Clinical Endocannabinoid Deficiency Reconsidered. Cannabis Cannabinoid Res. 2016 (PubMed)
• Englund A, et al. Does cannabidiol make cannabis safer? A randomised, double-blind, cross-over trial of cannabis with four different CBD:THC ratios. Neuropsychopharmacology. 2023 (PubMed)
• Russo EB. Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects. Br J Pharmacol. 2011 (PubMed Central)
• Florida Statutes, s. 381.986 (2026), Medical use of marijuana (Florida Senate)
• NIDA. Cannabis (Marijuana)