Cannabigerol

Synopsis

Cannabigerol (CBG): A Comprehensive Reference Article

1. Identity: Names, Chemical Profile, and Natural Sources

1.1 Nomenclature and Chemical Properties

Cannabigerol (CBG) is a cannabinoid from the plant Cannabis sativa that lacks psychotomimetic effects. Its precursor is the acidic form, cannabigerolic acid (CBGA), which is, in turn, a biosynthetic precursor of the compounds cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC). CBG has the molecular formula C₂₁H₃₂O₂ and naturally occurs in Cannabis sativa L. as a minor constituent derived from the decarboxylation of its acidic precursor, cannabigerolic acid (CBGA). Its CAS registry number is 25654-31-3. CBG is classified as a terpenophenolic phytocannabinoid. It is one of more than 120 identified cannabinoids found in the plant genus Cannabis.

1.2 Natural Sources and Plant Concentrations

CBG is the decarboxylated form of cannabigerolic acid (CBGA), the parent molecule from which other cannabinoids are biosynthesized. During plant growth, most of the CBG is converted into other cannabinoids, primarily tetrahydrocannabinol (THC) or cannabidiol (CBD), leaving about 1% CBG in finished plant material. Some strains, however, produce larger amounts of CBG and CBGA, while having low quantities of other cannabinoids, such as THC and CBD.

Normally, CBG appears as a relatively low concentration intermediate in the plant, but recent breeding work has yielded cannabis chemotypes lacking in downstream enzymes that express 100% of their phytocannabinoid content as CBG. Beyond its discovery in C. sativa, CBG has also been found in the phytochemical profile of an extract from Helichrysum umbraculigerum, considered to be the most abundant source of CBG.

1.3 Biosynthesis

The biosynthesis of CBG begins by loading hexanoyl-CoA onto a polyketide synthase assembly protein and subsequent condensation with three molecules of malonyl-CoA. This polyketide is cyclized to olivetolic acid via olivetolic acid cyclase, and then prenylated with a ten carbon isoprenoid precursor, geranyl pyrophosphate, using an aromatic prenyltransferase enzyme, geranyl-pyrophosphate—olivetolic acid geranyltransferase, to biosynthesize cannabigerolic acid, which can then be decarboxylated to yield CBG.

CBGA decarboxylation leads to the formation of neutral cannabinoid CBG through a chemical reaction catalyzed by heat. Cannabinoid biosynthesis is initiated with the synthesis of CBGA from geranyl pyrophosphate and olivetolic acid. Geranyl pyrophosphate and olivetolic acid serve as substrates for 2-O-geranyl olivetolic acid, 5-geranyl olivetolic acid, and 4-O-geranyl olivetolic acid. CBGA is the primary precursor for most of the cannabinoids. CBDA synthase directs the conversion of CBGA to CBDA, and decarboxylation of CBDA yields cannabidiol (CBD). Similarly, THCA synthase facilitates the formation of tetrahydrocannabinolic acid (THCA) from CBGA, with subsequent decarboxylation generating THC.

1.4 Common Preparations and Dosage Forms

CBG is commercially available in a variety of forms as a dietary supplement. Documented preparations include oral tinctures (commonly hemp-derived CBG dissolved in a carrier oil), capsules, topical preparations, and beverage powders. Oral tincture preparations have been used in clinical research, including 20 mg hemp-derived CBG tinctures. Oral capsule forms have also been studied, with one clinical protocol employing a 50 mg capsule of full-spectrum CBG. Beverage powder formulations combining CBG (50 mg) with other cannabinoids and nutritional ingredients have been evaluated in pilot studies. CBG can also be produced via yeast biosynthesis; one evaluation explored CBG produced via yeast biosynthesis for its anti-inflammatory and skin health-boosting properties.

2. Traditional and Historical Use

2.1 Historical Context of Cannabis sativa

It is important to note that, historically, cannabis was used as a whole-plant preparation. CBG as an isolated compound was unknown until the modern era; traditional practices involved preparations containing the full spectrum of cannabinoids and other plant constituents, of which CBGA/CBG would have been a minor component.

The herbal use of Cannabis sativa plant extract has a long history of 5,000 years. In ancient China, the extracts from the Cannabis sativa plant were applied to treat gout, malaria, digestive disorders, muscle spasms, and pain. Cannabis was introduced to Western medicine by William O'Shaughnessy, who proposed its use for the treatment of rheumatism and seizures.

Humans have cultivated cannabis throughout recorded history as a source of industrial fiber, seed oil, food, and medicine, and for religious, spiritual, and recreational purposes. The cannabis genus of plants has been cultivated and used for its medicinal and industrial benefits dating back to ancient times. Practitioners in ancient China targeted malaria, menstrual symptoms, gout, and constipation. During medieval times, cannabis was used for pain, epilepsy, nausea, and vomiting, and in Western medicine it was commonly used as an analgesic.

Cannabis sativa L. has been cultivated in China for millennia for use as a fiber, food, and medicine. References to cannabis are found throughout classical Chinese literature, including in many famous works of philosophy, poetry, agriculture, and medicine. Fiber-rich biotypes of cannabis (hemp) were extensively used in ancient China for clothing and the production of paper, rope, and fishing nets, and the achenes ("seeds") of cannabis have been continuously used in Chinese medicine for at least 1,800 years.

In contrast to the prominent use of the achenes in Chinese medicine, many applications of cannabis in early Western medicine focused on preparations made from the female flowering tops of drug varieties of cannabis, which were featured in early Western pharmacopoeia texts from the nineteenth to twentieth century.

2.2 Discovery of CBG as a Distinct Compound

CBG was purified from cannabis the same year as THC (Gaoni & Mechoulam, 1964), but cannabigerol lacks its psychotropic effects. After the isolation of THC, the main psychoactive constituent of C. sativa, over 100 phytocannabinoids have been found in this plant, one of these being CBG. A few years after the identification of THC, in vivo assays showed that the phytocannabinoid CBG is not psychotomimetic like the more well-known phytocannabinoid THC. However, it has been neglected and shadowed by THC for years because of its lower concentration and, paradoxically, probably for its lack of psychotomimetic activity.

3. Key Constituents and Mechanisms of Action

3.1 The Endocannabinoid System: CB1 and CB2 Receptors

CBG is considered a partial agonist at the CB1 receptor and CB2 receptor, as well as a regulator of endocannabinoid signaling. CBG, the parent phytocannabinoid compound, has a relatively weak partial agonistic effect at CB1 (Ki 440 nM) and CB2 (Ki 337 nM). cAMP, pERK, β-arrestin recruitment and label-free assays in HEK-293T cells expressing the receptors and treated with endocannabinoids or selective agonists proved that CBG is a partial agonist of CB₂R. The action on cells expressing heteromers was similar to that obtained in cells expressing the CB₂R. The effect of CBG on CB₁R was measurable but the underlying molecular mechanisms remain uncertain. The results indicate that CBG is indeed effective as regulator of endocannabinoid signaling.

3.2 Transient Receptor Potential (TRP) Channels

Research indicates that CBG can act as: (i) agonist/desensitizer of TRPA1 (EC₅₀ = 700 nM), (ii) agonist of TRPV1 (EC₅₀ = 1.3 μM), (iii) agonist of TRPV2 (EC₅₀ = 1.7 μM), and (iv) antagonist of TRPM8 channels (IC₅₀ = 160 nM). CBG may stimulate a range of receptors important for pain, inflammation, and heat sensitization.

3.3 Alpha-2 Adrenoceptor and 5-HT1A Receptor

A single study performed by binding techniques in mouse brain membranes revealed that CBG behaves as a potent α2-adrenoceptor (α2AR) agonist and moderately potent 5-HT₁A receptor antagonist, which may explain its biological activity considering its slight affinity for cannabinoid receptors. Specifically, CBG has been reported as an α2-adrenoceptor agonist at nanomolar levels (EC₅₀ = 0.2 nM), and is also able to antagonize [³⁵S]GTPγS binding upon stimulation of the 5HT1A receptor.

3.4 PPARγ and FAAH Inhibition

CBG acts as an agonist of the receptors of the TRPV family, PPARγ, and 5-HT1A, and as an antagonist of the receptor TRPM8. CBG weakly agonizes the action of CB1 and partially acts as an agonist on CB2 receptor. CBG also inhibits FAAH (fatty acid amide hydrolase), which results in increased anandamide levels.

3.5 Cyclooxygenase (COX) Enzyme Inhibition

Potential pharmacological targets for CBG include cyclooxygenase (COX-1 and COX-2) enzymes. It has been suggested that anti-inflammatory activity is a key factor in the development of colon cancer. COX-mediated anti-inflammatory activity of CBG has been studied at a concentration of 2.5 × 10⁻⁵ M, while CBGA has been tested at a concentration of 6.25 × 10⁻⁵ M. Both CBG and CBGA showed inhibition of the enzyme COX-1 of more than 30%. The same percentage (30%) of inhibition was shown by CBG and CBGA on COX-2 enzyme activity. However, CBG and CBGA inhibition of prostaglandin production was low, being less than 10%.

3.6 Metabolism

CBG is metabolized in the liver by the enzyme CYP2J2 to produce hydroxyl and di-oxygenated products. CBG and its oxidized CBG metabolites reduced inflammation in BV2 microglial cells stimulated with LPS. Overall, CBG is rapidly metabolized by human P450s to form oxidized metabolites that are bioactive.

The pharmacokinetics of CBG has not been sufficiently characterized in humans.

4. Scientific Evidence by Area of Use

The following sections distinguish carefully between preclinical evidence (cell-based and animal studies), which cannot be directly extrapolated to humans, and any available human/clinical evidence. As a general characterization, cannabigerol is currently being marketed as a dietary supplement, and much of what is known warrants further investigation to identify potential areas of therapeutic uses and hazards.

4.1 Anxiety and Mood

Human/Clinical Evidence (preliminary, single trial): Cannabigerol is a phytocannabinoid increasing in popularity, with preclinical research indicating it has anxiolytic and antidepressant effects; however, there were no published clinical trials to corroborate these findings in humans prior to 2024.

A double-blind, placebo-controlled crossover field trial was conducted with 34 healthy adult participants, who completed two sessions (with a one-week washout period) via Zoom. In each session, they provided ratings of anxiety, stress, mood, and subjective drug effects prior to double-blind administration of 20 mg hemp-derived CBG or placebo tincture. The research revealed that 20 mg of hemp-derived CBG significantly reduced feelings of anxiety at 20, 45 and 60 minutes after ingestion compared to a placebo. Stress ratings also decreased at the first time point compared to the placebo. The findings suggest that CBG decreases overall feelings of anxiety and stress and may improve memory without causing intoxication, impairment, or noticeable drug effects.

Limitations: The study enrolled only 34 participants who were existing cannabis users, used only self-report measures for anxiety and stress, and was conducted remotely. Replication in larger, more diverse samples including physiological measures and non-cannabis users is required. Moving forward, the research team is designing a new clinical trial to replicate their findings and include physiological measures such as heart rate, blood pressure, and cortisol levels.

Survey data: A prior survey study indicated that 51% of CBG users utilize it to manage anxiety, with 78% of these individuals finding it more effective than conventional anxiety medications. This constitutes self-reported, uncontrolled evidence and cannot establish causation or efficacy.

Preclinical evidence: In rat studies, CBG hindered the inhibitory effect produced by selective α2-adrenoceptor and 5-HT1A receptor agonists on the firing rate of noradrenergic locus coeruleus and serotonergic dorsal raphe nucleus neurons, and produced anxiolytic-like effects through 5-HT1A receptors.

4.2 Inflammatory Bowel Disease (IBD)

Preclinical evidence (animal models, no human trials): CBG given to mice with experimentally induced inflammatory bowel disease (IBD) showed therapeutic benefit in murine colitis, reduced nitric oxide production in macrophages (an effect being modulated by the CB2 receptor) and reduced reactive oxygen species (ROS) formation in intestinal epithelial cells. Experiments in mice have shown that CBG can decrease inflammation associated with inflammatory bowel disease.

Evidence strength: Exclusively preclinical (murine models). No human clinical trials for IBD have been published to date.

4.3 Neuroprotection and Neurodegenerative Disease

Huntington's Disease — preclinical: Researchers studied the effects of CBG, a nonpsychotropic phytocannabinoid, in two different in vivo models of Huntington's disease (HD). CBG was extremely active as a neuroprotectant in mice intoxicated with 3-nitropropionate (3NP), improving motor deficits and preserving striatal neurons against 3NP toxicity. In addition, CBG attenuated the reactive microgliosis and the upregulation of proinflammatory markers induced by 3NP, and improved the levels of antioxidant defenses. Using HD array analysis, researchers identified a series of genes linked to this disease whose expression was altered in R6/2 mice but partially normalized by CBG treatment. A modest improvement in the gene expression for brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), and PPARγ was also observed, as well as a small but significant reduction in the aggregation of mutant huntingtin in the striatal parenchyma in CBG-treated animals.

In vitro neuroprotection: Neuroprotective effects of CBG and CBD have been compared in experiments simulating oxidative stress and neurotoxicity as they occur in neurological pathologies in rats. CBG and CBD exert antioxidant activity in astrocytes exposed to hydrogen peroxide and restored the content of serotonin in the cortex. The effects of CBG have also been studied on human brain microvascular endothelial cells, pericytes, and astrocytes forming the blood-brain barrier under ischemic conditions. Through this experimental model, it has been shown that 10 μM of CBG reduced IL-6, lactate dehydrogenase, and DNA damage protein levels in astrocytes.

CBG may help reduce neuroinflammation, which is associated with various neurodegenerative conditions, such as Alzheimer's disease, Parkinson's disease, and multiple sclerosis. However, this evidence is exclusively from preclinical models.

Evidence strength: Preclinical (animal and cell models). No human trials have been published for any neurodegenerative indication.

4.4 Antibacterial Activity, Including MRSA

CBG has been determined to have antimicrobial properties in both in vivo and in vitro models. CBG has shown potent antibacterial activity against a broad spectrum of bacteria and antibiotic-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA). In a recent review, CBG was highlighted as a promising compound for fighting drug-resistant pathogens like MRSA. In a study in mice, CBG was found to be as effective as vancomycin in curing MRSA infections. Vancomycin is considered an effective alternative against multi-resistant staphylococci. However, much more research is needed to find out whether CBG is safe to use as an antibiotic.

Evidence strength: Preclinical (in vitro and mouse studies). No human clinical trials on CBG's antibacterial properties have been published.

4.5 Intraocular Pressure (Glaucoma)

Like other cannabinoids, CBG has been shown to have beneficial effects in glaucoma patients by reducing intraocular pressure, a primary risk factor for glaucoma. The endocannabinoid system (ECS) contributes to the control of intraocular pressure (IOP) by modulating both production and drainage of aqueous humor. CB1 receptors are located in the eye, and functional CB2 receptors are also expressed in the retina and trabecular meshwork. There is a growing body of evidence of the involvement of this system in mechanisms leading to the death of retinal ganglion cells, which is the end result of glaucoma.

Evidence strength: The cited evidence for CBG specifically and intraocular pressure is largely preclinical. Clinical evidence for isolated CBG in glaucoma has not been established.

4.6 Appetite Stimulation

CBG is an appetite stimulant, and it may help treat bladder contractions. Preclinical evidence: a study documented in the literature demonstrated that cannabigerol is a novel, well-tolerated appetite stimulant in pre-satiated rats.

Evidence strength: Preclinical (animal models). No human trials specifically examining CBG's appetite effects have been published.

4.7 Anti-Cancer (Antiproliferative) Effects

Experiments in mice have shown that CBG can slow the growth of colorectal cancer. In cells, it inhibits glioblastoma multiforme cells. Pre-clinical findings show that CBG possesses antitumoral activities.

Evidence strength: Exclusively preclinical (cell and mouse models). No human trials on CBG and cancer have been published.

4.8 Dermatological Applications (Skin Health)

Acne is a common skin pathology. The anti-acne effects of CBG on the viability and proliferation of sebocytes were observed through laboratory methods. CBG significantly reduced cell viability after a 24-hour treatment. CBG (10–20 mM) treatment for 24 hours significantly reduced lipogenesis stimulated by AEA. These results suggest the possibility that CBG may act as a partial agonist through the same pro-lipogenic signaling pathway on which AEA is active. CBG also suppressed inflammation caused by LPS on sebocytes.

Evidence strength: In vitro (cell-based) only. No human clinical trials on CBG for dermatological conditions have been published.

4.9 Bladder Function

CBG at concentrations ranging from 10⁻⁸ to 10⁻⁴ M reduced the contractions of mouse bladders induced by acetylcholine, without influencing bladder contractions induced by electrical field stimulation.

Evidence strength: Preclinical (animal tissue). No human studies on CBG for bladder conditions have been published.

4.10 Recovery from Exercise and Muscle Soreness

A randomized, double-blind, placebo-controlled, repeated-dose pilot study tested the safety, tolerability, and preliminary effects on recovery of a formulation containing cannabidiol (CBD; 35 mg), cannabigerol (CBG; 50 mg), beta-caryophyllene (BCP; 25 mg), and branched-chain amino acids (BCAAs). Cannabinoid-containing products are marketed to athletes as promoting recovery, in spite of a lack of data on their safety and effects. Because CBG was not tested in isolation in this study, conclusions about CBG specifically cannot be drawn.

Evidence strength: One small pilot study using a combination product; CBG's individual contribution to any observed effects cannot be isolated from this design.

4.11 Survey Data on Self-Reported Conditions

In a 2021 published clinical study of 127 patient surveys using a CBG product (>50% CBG in formulation): 73.9% claimed the superiority of CBG-predominant cannabis over conventional medicines for chronic pain, 80% for depression, 73% for insomnia, and 78.3% for anxiety; 44% reported no adverse events, with 16.5% noting dry mouth, 15% sleepiness, 11.8% increased appetite, and 8.7% dry eyes.

Important caveat: Survey data is inherently subject to placebo effects, recall bias, and the absence of a control group. These results do not constitute controlled clinical evidence.

5. Body Systems and Health Areas Associated with CBG

Nervous System / Neurological: CBG exhibits similar activity and affinity characteristics to Δ9-THC and CBD on cannabinoid receptors, but also has a unique affinity for other receptors, such as the α2AR and 5-HT1A receptors. CBG's diverse mechanisms translate into a wide range of potential therapeutic applications, including neuroprotection, anti-inflammation, antibacterial properties, hypotension, cancer treatment, pain management, and metabolic syndrome.
Gastrointestinal System: Preclinical evidence for therapeutic benefit in murine colitis through CB2 receptor-mediated anti-inflammatory effects.
Immune System: By interacting with G-protein-coupled receptors, CBG exhibits anti-inflammatory, antibacterial, and antifungal activities, as well as regulation of the redox balance and neuromodulatory effects.
Ocular System: Preclinical evidence for reduction in intraocular pressure via endocannabinoid receptor pathways in ocular tissue.
Integumentary System (Skin): In vitro evidence for effects on sebocyte proliferation, lipogenesis, and inflammation, with relevance explored for acne.
Musculoskeletal / Pain: Proposed through TRP channel modulation and anti-inflammatory pathways; evaluated preclinically and in small combined-product human pilot studies.
Metabolic System: Current studies suggest CBG has potential therapeutic effects on metabolic syndrome. Evidence is at the preclinical stage.

6. Dosages Reported in Published Research

The following dosages are reported only as described in identified sources and do not represent recommendations.

Anxiety trial (human, oral tincture): 20 mg hemp-derived CBG as an oral tincture was used in the double-blind, placebo-controlled crossover trial with 34 participants.
General wellbeing trial (human, oral capsule): A 50 mg capsule of full-spectrum CBG once daily was used in a 12-week observational/interventional study.
Sleep study protocol (human, oral): After a two-week run-in phase, participants were to begin a four-week treatment phase with a dose escalation from 25 mg daily CBG up to 50 mg CBG daily.
Recovery pilot study (human, oral, combination product): A beverage powder formulation containing CBG at 50 mg (alongside CBD 35 mg and other ingredients) was used in a randomized, double-blind, placebo-controlled repeated-dose pilot study.
Huntington's disease model (preclinical, mice, i.p.): CBG administered through daily intraperitoneal injections at 10 mg/kg in mice improved motor deficits, preserved striatal neurons, attenuated microgliosis, and reduced inflammatory markers induced by 3-nitropropionate.

7. Safety Considerations and Potential Interactions

7.1 Non-Psychotomimetic Profile

Cannabigerol (CBG) is a cannabinoid from the plant Cannabis sativa that lacks psychotomimetic effects. This is one of its most consistently reported properties across the literature. The Cuttler et al. (2024) human trial found that CBG decreased anxiety and stress without causing intoxication, impairment, or noticeable drug effects.

7.2 Adverse Effects Reported in Human Data

Possible side effects may include gastrointestinal upset, appetite changes, constipation, diarrhea, lightheadedness, dry mouth, dry eyes, sedation, insomnia, lower heart rate, itching, and possible serotonergic effects including tremors and mild agitation. In a 2021 published clinical study of 127 patient surveys using a CBG-predominant product, 44% reported no adverse events, with 16.5% noting dry mouth, 15% sleepiness, 11.8% increased appetite, and 8.7% dry eyes.

7.3 Pharmacokinetics and Metabolic Interactions

The pharmacokinetics of CBG have not been sufficiently characterized in humans. CBG is metabolized in the liver by the enzyme CYP2J2 to produce hydroxyl and di-oxygenated products. CBG and its oxidized CBG metabolites have been shown to reduce inflammation in BV2 microglial cells, and CBG is rapidly metabolized by human P450s to form oxidized metabolites that are bioactive.

Because CBG is metabolized by hepatic cytochrome P450 enzymes, the possibility of pharmacokinetic drug-drug interactions with other medications processed by the same pathways exists, though this has not been systematically evaluated in humans for CBG specifically. Unlike CBD, little research has been performed on this unregulated molecule, and much of what is known warrants further investigation to identify potential areas of therapeutic uses and hazards.

7.4 Regulatory Status and Evidence Gaps

Cannabigerol is currently being marketed as a dietary supplement. Despite its promising effects, CBG is largely unregulated and under-researched compared to other cannabinoids like CBD, highlighting the need for further studies to understand its safety and efficacy. CBG is under laboratory research to determine its pharmacological properties and potential effects in disease conditions, with no conclusions about therapeutic effects or safety as of 2021.

CBG has emerged as a potential therapeutic agent with a diverse range of effects. Although research on CBG is still in its early stages, its unique molecular mechanism and promising therapeutic profile warrant further exploration.

7.5 Summary of Evidence Strength

The preponderance of evidence for CBG across all health areas remains preclinical — derived from cell cultures and animal models. CBG has a wide variety of potential medical uses, but virtually all of the studies that have been done on it have been done in animals, so it is difficult to fully extrapolate to humans. As of the time of this writing, the most robust human evidence is a single small double-blind crossover trial demonstrating acute anxiolytic and stress-reducing effects at 20 mg oral dose (Cuttler et al., 2024, Scientific Reports), and a small survey study on self-reported outcomes. Controlled human trials for other proposed indications — IBD, neuroprotection, antibacterial use, appetite, glaucoma, and anticancer effects — have not yet been published.