The Endocannabinoid System: Receptors, Endocannabinoids, and the Role of CBD

The endocannabinoid system is the internal regulatory system that CBD and other cannabinoids connect with. Understanding how it works is key to understanding why these molecules can affect functions as varied as sleep, pain, mood, and inflammation.

The endocannabinoid system, often abbreviated as ECS, is a lipid signaling network present in all vertebrates. It plays a central role in maintaining homeostasis, meaning the body's ability to maintain a stable balance in the face of internal and external variations.

It was discovered in the 1990s, initially during research on THC. Scientists sought to understand why cannabis affected the brain and discovered that the human body has its own receptors for these molecules, and more importantly, that it produces its own similar molecules: endocannabinoids.

Since then, over 12,000 scientific articles have been published on the subject, and the ECS is now recognized as one of the body's most important regulatory systems, involved in functions as diverse as pain, sleep, mood, memory, appetite, inflammation, and immune response.

The endocannabinoid system relies on three elements that work together:

Cannabinoid receptors

These are the anchor points of the system, located on the cell surface. The two main ones are:

There are also so-called "orphan" receptors such as GPR55, GPR18, and TRPV1 channels, which interact with cannabinoids and broaden the system's scope of action, although their precise role is still being studied.

Endocannabinoids

These are molecules naturally produced by the body to activate these receptors. The two main ones are:

• Anandamide (AEA): Its name comes from the Sanskrit word ananda, meaning "bliss". It primarily binds to CB1 receptors and plays a role in regulating pain, stress, mood, and memory. Its half-life is short: it is rapidly degraded by an enzyme called FAAH (fatty acid amide hydrolase).
• 2-arachidonoylglycerol (2-AG): Present in higher concentrations in the body than anandamide, it binds to both CB1 and CB2 receptors. It plays a key role in regulating inflammation and immune response. It is degraded by the enzyme MAGL (monoacylglycerol lipase).

These endocannabinoids function as retrograde messengers: they are produced on demand by the cell receiving a signal, then travel backward to the sending cell to modulate that signal. This is a very precise regulatory mechanism, quite different from most classic neurotransmitters.

Synthesis and degradation enzymes

Endocannabinoids are not stored like other neurotransmitters. They are synthesized on demand, then rapidly degraded after fulfilling their role. The enzymes that manage this cycle, primarily FAAH and MAGL, are highly studied therapeutic targets: inhibiting FAAH, for example, prolongs the action of anandamide without introducing it from outside.

Unlike THC, CBD does not bind directly to CB1 or CB2 receptors with high affinity. Its mechanism of action is more indirect and complex, which partly explains why it does not have a psychoactive effect.

CBD's identified mechanisms of action include:

• FAAH inhibition: CBD slows down the enzyme that degrades anandamide, which increases the lifespan of this natural molecule in the body and indirectly amplifies its action on CB1 receptors. This is one of the most studied mechanisms to explain CBD's anxiolytic effects.
• Allosteric modulation of CB1 receptors: CBD can change the shape of CB1 receptors to modulate their response to THC or anandamide, without directly activating them.
• Activation of TRPV1 receptors: These receptors, involved in pain and heat perception, are directly activated by CBD.
• Interaction with 5-HT1A receptors: CBD interacts with these serotonin receptors, which may contribute to its effects on mood and anxiety.
• Interaction with GPR55: This receptor, sometimes called the "third cannabinoid receptor", is involved in regulating blood pressure, bone density, and certain inflammatory processes.

The endocannabinoid system is involved in a remarkable number of physiological processes. A review published in the International Journal of Molecular Sciences in November 2025 describes it as a central regulatory system for the nervous, immune, and digestive systems, playing a role in maintaining homeostasis at all levels.

The concept of endocannabinoid deficiency

A hypothesis, proposed by researcher Ethan Russo and documented in a systematic review in PLoS One, suggests that a dysfunction of the endocannabinoid system, an "endocannabinoid deficiency," could be involved in certain chronic pathologies such as migraine, fibromyalgia, and irritable bowel syndrome. This hypothesis remains exploratory and not clinically proven to date, but it guides a part of current research on cannabinoid therapeutics.

This article contains general information for educational purposes and is not a substitute for professional medical advice.