Cannabinoid Encyclopedia

How cannabinoids work

What is GPR55?

A simple explanation of GPR55, why cannabinoid researchers study it, and what its biology can and cannot tell us.

Updated July 2026 18 research sources Mostly early-stage research

The short answer

Where GPR55 fits into cannabinoid biology

GPR55 is a biological target studied to understand how cannabinoids affect cells and signaling. Research on CBD, THC, Cannabinoids, and Endocannabinoids helps explain possible mechanisms. This page brings together 3 human-study sources, 14 research reviews, and 1 lab, animal, or mechanism source. Most of the current evidence is preclinical or focused on biological mechanisms. A mechanism alone does not prove that a cannabinoid will produce a health benefit in people. 1

Choose your next step

Want the quick path or the full picture?

Use this guide the way you need to. Start with the practical question, then open the study detail only when it helps answer something about GPR55.

What researchers studiedSee the main areas and the evidence behind each one. Safety and limitsKeep product, dose, medications, and context in view. Open the sourcesGo directly to the studies and references used here.

Key takeaways

What to know first

  1. 1

    Research on GPR55 covers CBD, THC, and Cannabinoids; those areas should not be combined into one claim. 1

  2. 2

    Most of the current evidence is preclinical or focused on biological mechanisms. 2

  3. 3

    Dose, formulation, route, study population, and outcome can change how closely a study applies to a real-world question. 3

Research areas

What researchers studied about GPR55

These are the main questions represented in the current literature. Each link opens a source used to build the overview.

Mostly mechanism-focused

CBD

Studies examine how CBD connects with GPR55 or closely related target biology. These findings help explain signaling and pharmacology, not a guaranteed health effect. 2

Too limited for a firm answer

THC

Studies examine how THC connects with GPR55 or closely related target biology. These findings help explain signaling and pharmacology, not a guaranteed health effect. 3

Too limited for a firm answer

Cannabinoids

Studies examine how Cannabinoids connects with GPR55 or closely related target biology. These findings help explain signaling and pharmacology, not a guaranteed health effect. 4

Mostly mechanism-focused

Endocannabinoids

Studies examine how Endocannabinoids connects with GPR55 or closely related target biology. These findings help explain signaling and pharmacology, not a guaranteed health effect. 5

How strong is the research?

Not every study answers the same question

This page separates research in people, research reviews, and earlier-stage biology before interpreting the larger question.

3 sources

Human studies

Research involving people is closest to everyday health questions. The product, dose, population, and outcome still determine what each study can show.

14 sources

Reviews and evidence summaries

Reviews can compare several studies at once. Their conclusion is only as strong and as relevant as the studies they include.

1 source

Lab, animal, and mechanism research

Early-stage research can explain biological interest. It cannot, by itself, show that the same effect happens in people.

What these studies actually looked at

The research on GPR55 is not one kind of study. This source set includes 14 narrative or expert reviews, 2 cell or laboratory studies, and 1 animal study. 3

The recorded populations or models include people or patients (9 sources), animal models (2 sources), and cells or tissue models (2 sources). A result from one group or model should not be assumed to apply to another. 4

The most common recorded outcome focus is gPR55 receptor activity, binding, signaling, or pharmacology (18 sources). Closely related outcome names can still describe different measurements. 5

The GPR55 source set also contains findings or reviews that remain too limited, indirect, or mixed for a broad answer. That uncertainty is part of the result, not an empty space to fill with assumptions. 6

Examples from the literature

What did the studies actually look at?

Each example names the research question and the study details recorded for that source.

narrative or expert review

GPR55 - a putative "type 3" cannabinoid receptor in inflammation.

On this page, this source examines Cannabinoids activity involving GPR55. 1

Study type
narrative or expert review
Outcome focus
gPR55 receptor activity, binding, signaling, or pharmacology
Evidence stage
evidence still limited

narrative or expert review

A narrative review of molecular mechanism and therapeutic effect of cannabidiol (CBD).

On this page, this source examines CBD activity involving GPR55. 2

Study type
narrative or expert review
Population or model
people or patients
Outcome focus
gPR55 receptor activity, binding, signaling, or pharmacology
Evidence stage
evidence still limited

narrative or expert review

Cannabinoids in the landscape of cancer.

On this page, this source examines THC activity involving GPR55. 3

Study type
narrative or expert review
Population or model
cells or tissue models
Outcome focus
gPR55 receptor activity, binding, signaling, or pharmacology
Evidence stage
evidence still limited

narrative or expert review

Cannabinoid Receptor-Related Orphan G Protein-Coupled Receptors.

On this page, this source examines Cannabinoids activity involving GPR55. 4

Study type
narrative or expert review
Population or model
people or patients
Outcome focus
gPR55 receptor activity, binding, signaling, or pharmacology
Evidence stage
evidence still limited

narrative or expert review

Molecular networks underlying cannabinoid signaling in skeletal muscle plasticity.

On this page, this source examines Endocannabinoids activity involving GPR55. 5

Study type
narrative or expert review
Population or model
cells or tissue models
Outcome focus
gPR55 receptor activity, binding, signaling, or pharmacology
Evidence stage
evidence still limited

Safety and limits

What should readers keep in mind?

Research on GPR55 should be read beside safety. A compound can be non-intoxicating or naturally occurring and still have pharmacologic effects, side effects, interactions, or product-quality concerns. 2

Research doses are descriptions of what a study tested. They are not personal dosing instructions. Questions involving medications, pregnancy, children, driving, liver health, heart health, or serious symptoms deserve professional medical guidance.

Drug interactions Pregnancy and children Driving and impairment All safety topics

Common questions

Questions people ask

What does GPR55 do?

GPR55 is studied as part of cannabinoid-related biology and signaling. The exact role depends on the tissue, compound, and experimental setting. 7

Does a biological mechanism prove a health effect?

No. A mechanism can explain why an idea is plausible, but human studies are needed to test whether it changes a health outcome. 8

What research is linked to GPR55?

The main areas on this page include CBD, THC, Cannabinoids, and Endocannabinoids. The source links show the study type behind each area. 9

Sources

Read the research

The numbered sources below support the main overview. Links open the PubMed record or DOI in a new tab.

  1. 1
    GPR55 - a putative "type 3" cannabinoid receptor in inflammation. narrative or expert review; evidence still limited PubMed 26669245 DOI 10.1515/jbcpp-2015-0080
  2. 2
    A narrative review of molecular mechanism and therapeutic effect of cannabidiol (CBD). narrative or expert review; evidence still limited PubMed 35083862 DOI 10.1111/bcpt.13710
  3. 3
    Cannabinoids in the landscape of cancer. narrative or expert review; evidence still limited PubMed 34259916 DOI 10.1007/s00432-021-03710-7
  4. 4
    Cannabinoid Receptor-Related Orphan G Protein-Coupled Receptors. narrative or expert review; evidence still limited PubMed 28826536 DOI 10.1016/bs.apha.2017.04.004
  5. 5
    Molecular networks underlying cannabinoid signaling in skeletal muscle plasticity. narrative or expert review; evidence still limited PubMed 35862111 DOI 10.1002/jcp.30837
  6. 6
    Cannabinoid receptor ligand bias: implications in the central nervous system. narrative or expert review; evidence still limited PubMed 27835801 DOI 10.1016/j.coph.2016.10.005
  7. 7
    Cannabis and Endocannabinoid Signaling in Epilepsy. narrative or expert review; evidence still limited PubMed 26408165 DOI 10.1007/978-3-319-20825-1_10
  8. 8
    Epilepsy, neuroinflammation and cannabidiol What do we know thus far? narrative or expert review; evidence still limited PubMed 41560741 DOI 10.3389/fphar.2025.1749260
  9. 9
    GPR55, a lysophosphatidylinositol receptor with cannabinoid sensitivity? narrative or expert review; evidence still limited PubMed 20370712 DOI 10.2174/156802610791164229
  10. 10
    GPR55: a new member of the cannabinoid receptor clan? narrative or expert review; evidence still limited PubMed 17876300 DOI 10.1038/sj.bjp.0707464
  11. 11
    Is GPR55 an anandamide receptor? narrative or expert review; evidence still limited PubMed 19647110 DOI 10.1016/s0083-6729(09
  12. 12
    Pharmacological characterization of GPR55, a putative cannabinoid receptor. narrative or expert review; evidence still limited PubMed 20298715 DOI 10.1016/j.pharmthera.2010.02.004
See all 18 research sources

This complete source list is the deeper research layer for the page. Study type and evidence context are shown when they are available in the current record.

  1. Cannabinoid Receptor-Related Orphan G Protein-Coupled Receptors. narrative or expert review; evidence still limited / 1 linked research note PubMed 28826536
  2. Cannabinoids in the landscape of cancer. narrative or expert review; evidence still limited / 1 linked research note PubMed 34259916
  3. The enigmatic pharmacology of GPR55. narrative or expert review; evidence still limited / 1 linked research note PubMed 19233486
  4. Molecular networks underlying cannabinoid signaling in skeletal muscle plasticity. narrative or expert review; evidence still limited / 1 linked research note PubMed 35862111
  5. Is GPR55 an anandamide receptor? narrative or expert review; evidence still limited / 1 linked research note PubMed 19647110
  6. The GPR55 ligand L-alpha-lysophosphatidylinositol promotes RhoA-dependent Ca2+ signaling and NFAT activation. cell or laboratory study; mechanism-focused research / 1 linked research note PubMed 18757503
  7. GPR55 - a putative "type 3" cannabinoid receptor in inflammation. narrative or expert review; evidence still limited / 1 linked research note PubMed 26669245
  8. Cannabinoid receptor ligand bias: implications in the central nervous system. narrative or expert review; evidence still limited / 1 linked research note PubMed 27835801
  9. GPR55, a lysophosphatidylinositol receptor with cannabinoid sensitivity? narrative or expert review; evidence still limited / 1 linked research note PubMed 20370712
  10. A narrative review of molecular mechanism and therapeutic effect of cannabidiol (CBD). narrative or expert review; evidence still limited / 1 linked research note PubMed 35083862
  11. The novel endocannabinoid receptor GPR55 is activated by atypical cannabinoids but does not mediate their vasodilator effects. animal study; mechanism-focused research / 1 linked research note PubMed 17704827
  12. The Endocannabinoid System of Animals. narrative or expert review; evidence still limited / 1 linked research note PubMed 31527410
  13. GPR55: a new member of the cannabinoid receptor clan? narrative or expert review; evidence still limited / 1 linked research note PubMed 17876300
  14. Pharmacological characterization of GPR55, a putative cannabinoid receptor. narrative or expert review; evidence still limited / 1 linked research note PubMed 20298715
  15. The orphan receptor GPR55 is a novel cannabinoid receptor. cell or laboratory study; mechanism-focused research / 1 linked research note PubMed 17876302
  16. Cannabis and Endocannabinoid Signaling in Epilepsy. narrative or expert review; evidence still limited / 1 linked research note PubMed 26408165
  17. Epilepsy, neuroinflammation and cannabidiol What do we know thus far? narrative or expert review; evidence still limited / 1 linked research note PubMed 41560741
  18. Interacting binding insights and conformational consequences of the differential activity of cannabidiol with two endocannabinoid-activated G-protein-coupled receptors. mechanism-focused research / 1 linked research note PubMed 36016551