The Endocannabinoid System: Why Cannabis Works
What Researchers Found About Chronic Pain and Cannabis
The Study at a Glance
Published
International Journal of Molecular Sciences, 2021
Researchers
University of the West Indies (United States)
Study Type
Systematic ReviewKey Finding
The endocannabinoid system (ECS) regulates pain, mood, appetite, memory, and immune function. Because this system is involved in so many conditions—from chronic pain to neurological diseases—cannabis-based medicines have potential for treating diverse disorders.
Key Finding: The endocannabinoid system (ECS) regulates pain, mood, appetite, memory, and immune function. Because this system is involved in so many conditions—from chronic pain to neurological diseases—cannabis-based medicines have potential for treating diverse disorders.
What Researchers Studied About Chronic Pain and Cannabis
Why does cannabis affect so many different conditions? The answer lies in the endocannabinoid system (ECS)—a signaling system that exists naturally in our bodies.
This comprehensive review examines how the ECS works and why it represents such a promising target for treating various diseases.
Understanding the ECS helps explain both the therapeutic potential and the wide-ranging effects of cannabis-based medicines.
How This Systematic Review Was Conducted
Researchers conducted an in-depth review of the endocannabinoid system:
• Examined the components of the ECS (receptors, endocannabinoids, enzymes) • Reviewed physiological functions regulated by the ECS • Analyzed ECS involvement in various diseases • Evaluated potential for cannabinoid-based drug development
Chronic Pain Treatment Results
The Main Results:
- 1ECS maintains homeostasis (internal balance) throughout the body
- 2Regulates: pain, mood, appetite, memory, immune function, fertility
- 3Involved in diseases: cancer, cardiovascular, neurological
- 4Two main receptors: CB1 (mostly brain) and CB2 (mostly immune)
- 5Body makes its own cannabinoids (endocannabinoids)
- 6Cannabis compounds interact with this existing system
By the Numbers
| Statistic | What It Means |
|---|---|
| Every | major organ system has ECS components |
| CB1 & CB2 | two main cannabinoid receptors |
| Diverse | conditions potentially treatable via ECS |
| Natural | system that exists in all mammals |
major organ system has ECS components
two main cannabinoid receptors
conditions potentially treatable via ECS
system that exists in all mammals
What This Means for Chronic Pain Patients
Understanding the endocannabinoid system helps explain why cannabis works:
Your body has a cannabis system: • The ECS exists naturally in your body • Your body makes its own cannabinoids (endocannabinoids) • Cannabis compounds (like THC and CBD) interact with this system
What the ECS regulates: • Pain sensation • Mood and emotional balance • Appetite and metabolism • Memory and learning • Sleep • Immune function • Reproduction
Why cannabis affects so many conditions: The ECS is involved in maintaining balance throughout the body. When this system is dysregulated, it can contribute to various diseases. Cannabis compounds can help restore balance.
What this means for treatment: Cannabis-based medicines work by influencing a natural system your body already uses. This explains both the therapeutic effects and why cannabis affects multiple symptoms simultaneously.
Quick Answers: Chronic Pain and Cannabis
Direct answers based on the findings of this study:
Research Summary: Answers are based on published peer-reviewed studies and represent research findings, not medical recommendations. Individual results may vary. Always consult a healthcare provider before making treatment decisions.
What is the endocannabinoid system?
It's your body's natural cannabis-like system—receptors throughout your body that regulate pain, mood, appetite, memory, and more. THC and CBD work because they interact with this system you already have.
Source: Pacher et al., International Journal of Molecular Sciences, 2021 (PMID: 34502379)
How does weed affect your body?
THC and CBD interact with your endocannabinoid system—a natural system with receptors that regulate pain, mood, appetite, and memory. THC activates CB1 receptors (causing the "high"); CBD works more indirectly on multiple receptors.
Source: Pacher et al., International Journal of Molecular Sciences, 2021 (PMID: 34502379)
Why does marijuana help so many different things?
Your endocannabinoid system regulates functions throughout your entire body—pain, mood, appetite, memory, immune response, sleep. Because this system is everywhere, cannabis can affect multiple symptoms at once.
Source: Pacher et al., International Journal of Molecular Sciences, 2021 (PMID: 34502379)
This is educational content, not medical advice
The research summarized here is for informational purposes only. Individual results may vary, and what works in studies may not work the same way for everyone. Always consult with a qualified healthcare provider before making changes to your treatment plan or starting medical cannabis therapy.
Important Limitations
This study has some caveats to keep in mind when interpreting the results:
- Basic science review—clinical applications still developing
- Individual ECS function varies
- Not all potential applications clinically proven
- Optimal ways to target ECS still being researched
- Risk-benefit balance varies by condition
The Bottom Line on Cannabis for Chronic Pain
This review explains why cannabis affects so many conditions: our bodies have a built-in endocannabinoid system (ECS) that regulates pain, mood, appetite, memory, and more. Cannabis compounds interact with this existing system. Understanding the ECS helps explain both the therapeutic potential and the wide-ranging effects of cannabis-based medicines. While clinical applications are still developing, the ECS represents one of the most promising targets for new treatments.
Do You Qualify for Medical Marijuana?
If you're living with Chronic Pain, you may qualify for a medical marijuana card. Our licensed physicians can evaluate you from home via telehealth.
Related Research & Resources
Related Research
- Medical Cannabis for Cancer Patients: Real-World Results
- Can Cannabis Treat Mental Health Conditions? The Evidence
- Clinical Practice Guidelines: Cannabis for Chronic Pain & Co-Occurring Conditions (2024)
- Medical Cannabis for Chronic Pain: A Practical Review
- Teen Cannabis Use Linked to Depression and Suicide Risk: Major Study
Get Your Card
This condition qualifies for medical marijuana in:
Source
Lowe H, Toyang N, Steele B, et al. "The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases" International Journal of Molecular Sciences. 2021. DOI: 10.3390/ijms22179472
Important Information
Not Medical Advice: This research summary is for educational purposes only. It should not be used to diagnose, treat, cure, or prevent any disease or medical condition. Always consult a qualified healthcare provider before starting or changing any treatment.
Individual Variation: Research findings represent group averages. Your individual response to cannabis may differ based on genetics, other medications, underlying conditions, and many other factors.
Last reviewed: January 24, 2026
Important Notices
Research Summary Disclaimer
This content represents our interpretation of published scientific research for educational purposes. It should not be used to make treatment decisions without consulting a qualified healthcare provider. Individual results may vary from study findings.
FDA Notice
These statements have not been evaluated by the FDA. Cannabis is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not approved cannabis for any medical condition except specific prescription medications.
Copyright & Fair Use
Research summaries are provided under fair use (17 U.S.C. § 107) for educational purposes. We provide brief summaries with attribution, not full reproductions. All studies remain the intellectual property of their respective authors and publishers.
Data Sources
Study information sourced from PubMed®, U.S. National Library of Medicine. Inclusion does not imply endorsement by NLM, NIH, or the federal government.
For complete information, see our Terms of Use and Research Content Policy.
FAQs: Cannabis for Chronic Pain
What is the endocannabinoid system?
It is your body's natural signaling system. The ECS has receptors (CB1 and CB2), your body's own cannabinoids (endocannabinoids), and enzymes. It regulates pain, mood, appetite, memory, immune function, and more.
Why does cannabis affect so many conditions?
It maintains balance in nearly every organ system. The endocannabinoid system regulates balance throughout the body. Cannabis compounds interact with this widespread system, explaining effects on pain, mood, sleep, and other functions.
Does everyone have cannabinoid receptors?
Yes. All mammals have an endocannabinoid system with cannabinoid receptors. CB1 receptors are concentrated in the brain; CB2 receptors are mainly in immune tissues. Your body makes its own cannabinoids to activate these receptors.