Why does an endocannabinoid system exist in our body?

The science behind this

A system that came before medicinal cannabis

For a long time it was believed that cannabinoid receptors existed only because they reacted to the compounds present in the Cannabis sativa plant. The story was exactly the other way around.

First the CB1 and CB2 receptors were discovered. Then researchers found that the body itself produced molecules capable of activating them, such as anandamide and 2-AG. That finding revealed that the body already had a fully functional communication system long before its interactions with phytocannabinoids were ever studied.

The goal was never to "respond to cannabis"

From an evolutionary perspective, the endocannabinoid system did not appear so that humans could react to a plant. Its function is far more fundamental: it helps different organs and tissues communicate with one another when the body needs to recover its balance.

The phytocannabinoids in cannabis, such as CBD or THC, simply have chemical structures capable of interacting with components of that biological network. In other words, cannabis found a door that already existed. It was not the body that built a door for cannabis.

A regulator, not a controller

Unlike systems such as the cardiovascular or the digestive one, the endocannabinoid system does not have a single function. It acts as a regulator that helps coordinate numerous physiological processes when one of them drifts away from balance. Among them are:

• The stress response.
• The perception of pain.
• Sleep.
• Appetite.
• Memory.
• The immune response.
• Inflammation.
• Energy metabolism.

That's why it's so hard to describe it in a single word. Its role is not to "switch on" or "switch off" functions, but to modulate them when necessary.

Homeostasis: the true purpose

There is one word that captures the function of the endocannabinoid system better than any other: homeostasis. It is the body's ability to keep internal conditions relatively stable, even when the environment changes constantly.

Think about body temperature. Whether it's cold or hot outside, the body works to stay close to 37 °C. The same happens with hundreds of biological processes. The endocannabinoid system takes part as a network that helps detect imbalances and modulate the body's response to recover stability. It doesn't work alone, but it does collaborate with the body's other regulatory systems.

An ancient and remarkably conserved system

One of the most fascinating aspects of the endocannabinoid system is its evolutionary history. Various components of this network appear, with different degrees of conservation, across numerous animal groups, which suggests it is a very old biological mechanism and valuable for survival. If evolution preserves a system for millions of years, it's usually because it serves important functions for the body.

So… what does CBD actually do?

Understanding why the endocannabinoid system exists also changes the way we understand CBD. CBD does not "create" balance on its own. Nor does it replace the endocannabinoid system. What it does is interact with a biological network the body already uses to regulate multiple processes. In that sense, CBD doesn't introduce an entirely new mechanism: it takes part in one the body has used for millions of years.

What we know today

The evidence supports fairly solidly that:

• The endocannabinoid system is a biological network of the body itself.
• Its main function is related to maintaining homeostasis.
• The body produces its own endocannabinoids, independently of cannabis use.
• Phytocannabinoids can interact with components of this system because they share structural similarities with endogenous molecules and because the network already existed.

What is still being researched

• Exactly how some components of the endocannabinoid system evolved.
• The specific function of lesser-known receptors and mediators.
• How the endocannabinoid system interacts with other signaling networks in the body.
• Its potential role in different diseases and therapeutic strategies.

Conclusion

The endocannabinoid system doesn't exist so the body can respond to cannabis. It exists so the body can respond to itself. Its purpose is to help maintain balance in the face of the constant changes that occur every day: from an injury or an infection to stress, exercise, or lack of sleep.

Perhaps that's the most important idea for understanding cannabinoids. Cannabis didn't invent this system. It simply revealed one of the most fascinating biological networks that had always been inside us.

Further reading

1. Di Marzo V, et al. The Endocannabinoid System: Its General Strategy of Action, Tools for Its Pharmacological Manipulation and Potential Therapeutic Exploitation. Pharmacological Research.
2. Ligresti A, et al. Possible Endocannabinoid Control of Human Reproduction via Homeostasis. PMC Review.
3. Harvard Health Publishing. The Endocannabinoid System: Essential and Mysterious.
4. Hiding in Plain Sight: The Discovery of the Endocannabinoid System. International League Against Epilepsy (ILAE).