Preliminary cell culture and animal studies have suggested that cannabigerol (CBG) may be efficacious in fighting cancer cell development and progression in a number of cancer cell lines. But this non-intoxicating cannabinoid may also prove useful in improving quality of life for cancer patients and improving treatment outcomes. So, how have scientific studies demonstrated the efficacy of CBG against the symptoms of conventional cancer treatments?
Nausea & Vomiting
One of the primary concerns for patients undergoing cancer therapy is the onset of debilitating nausea and vomiting. While current antiemetic (anti-vomiting) therapies have been highly effective at reducing chemo-induced vomiting, nausea remains poorly understood with very limited treatment options due to its subjective nature.
While evidence is scant on its ability to treat nausea and emesis directly, CBG concentration may be worth considering when choosing the best cannabis products to treat symptoms. In a 2011 study published in Psychopharmacology, investigators described two important findings on CBG’s potential potency.
First, CBG was able to suppress acute nausea at relatively low doses (1mg/kg) when given to mice through injection—notably, not a method found on the shelves at local dispensaries. The effect disappeared at higher concentrations suggesting dose-dependent performance—a good reminder that less is often more.
Inversely, when injected at identical doses (5mg/kg), CBG blocked the antiemetic effects of cannabidiol (CBD)—a cannabinoid with proven vigor against chemo-induced vomiting. By deactivating the same serotonin receptor CBD activated, CBG suppressed the beneficial effects of CBD when given at the same dose.
As the study’s authors pointed out, concentration of these opposing cannabinoids in a specific cannabis chemovar or product may be important to consider when choosing chemo-related cannabis therapies. However, with the proven potency of THC to treat nausea and vomiting, it is also worth noting that no such competitive nature between it and CBG has been uncovered.
Loss of Appetite & Cachexia
Loss of appetite and the development of a muscle wasting syndrome called cachexia is common to many chronic illnesses and especially devastating in late-stage cancer patients. The National Cancer Institute states that nearly one-third of cancer deaths can be attributed to the severe weight loss and “metabolic mutiny” associated with cachexia.
According to a 2019 study, the onset of these symptoms can have a dose-limiting effect on chemotherapy success, compromising quality of life and mortality. Showing potential to address that issue, investigators found CBG to be a well-tolerated appetite stimulant. Given that chemotherapy patients often report appetite loss, altered food palatability and early satiety, the authors noted that CBG may have the potential to lessen these side effects.
The authors also emphasized that, while THC has been used for decades to treat chemo-induced appetite loss and nausea, its tendency to create physical and cognitive side effects limits clinical utility. Additionally, they noted that THC had little effect on improving weight loss.
But where THC failed, CBG succeeded. The study found that not only did CBG’s efficacy come without the cognitive and neuromotor changes associated with THC, but this non-intoxicating cannabinoid also robustly improved weight loss induced by Cisplatin, a chemotherapy medication used to treat a number of cancer types. Furthermore, widespread metabolic dysregulation created by Cisplatin treatment, with relevancy to gut function and liver toxicity, were all partially normalized by CBG. These findings built on concurrent research into the beneficial effects of CBG on metabolic homeostasis.
Characterized by painful nerve damage or dysfunction within the peripheral nervous system, peripheral neuropathy is a common side effect for many cancer patients. This can come as either a direct response to the disease or its treatment. Complex causes and symptoms as well as limited pharmaceutical effectiveness have made treating peripheral neuropathy a primary challenge in pain control, encouraging scientific investigation into new drug types.
In an overview of its medical uses from the Handbook of Cannabis and Related Pathologies, the authors noted an increasing body of evidence to suggest the anti-inflammatory and pain-relieving properties of CBG. Specifically, a GW Pharmaceuticals patent application described CBG’s efficacy against animal models of neuropathic pain. Here, CBG was described as superior to CBD with improvements increasing after three days of administration, suggesting that its influence may build over time. Additionally, at the lowest dose given (2.5mg/kg), CBG was found to be the most effective across all tested cannabinoids.
Studies of neuropathy associated with other conditions like diabetes and multiple sclerosis also suggest a potential therapeutic role for CBG. A 2018 investigation into the role of aldose reductase (ALR2) inhibition for the prevention and treatment of diabetic complications, including neuropathic pain, demonstrated the benefits of CBG and CBG-rich extracts. The authors showed significant ALR2 inhibition with CBG-rich botanical extractions and illustrated its therapeutic potential in many diseases, including inflammation and cancer.
Additionally, a 2011 study described the role of ALR2 inhibition in the prevention and treatment of colon and liver cancers, improvements in appetite and cachexia, and in the reduction of ALR2 overexpression associated with an increase in chemotherapeutic drug resistance. All relevant to patients undergoing cancer treatment.
Like most cannabinoids, even isolated CBG has proven capable of acting at many targets in the body. Another promising mechanism of action for CBG against neuropathies is its potent alpha-2 (α2) adrenoceptor activation, where a 1993 study showed α2 agonism was successful in treating chronic neuropathic pain better than opioids. A 2010 study confirmed this α2 activation, remarking on the therapeutic potential of CBG as a pain reliever and antidepressant via this engagement.
Anxiety & Depression
Cancer patients are often pressured to think positively. While the evidence for genuine improvement through positivity is mixed and contextual, there is little argument among scientists on how stress can challenge the immune system.
The American Cancer Society describes the development of feelings of depression, anxiety and fear as common and normal responses to a life-changing cancer diagnosis. Changes in self-esteem, work and family relationships and the onset of physical symptoms such as pain, nausea, and fatigue can lead to emotional distress. And fear of pain and suffering, in addition to all the unknowns that lie ahead, certainly play a role in the likelihood of an increase in anxiety and depression, which can ultimately hinder positive cancer-treatment outcomes. In a 2017 review of cannabis pharmacology, neuroscientist Dr. Ethan Russo described several actions CBG may take to improve symptoms of depression and anxiety.
Pulling from a 1975 study, Russo noted that CBG was found to be a more effective gamma-aminobutyric acid (GABA) uptake inhibitor than both THC and CBD. By allowing this neurotransmitter, known for its calming effects, to remain in circulation within the body, CBG may help reduce feelings of anxiety, stress and fear. Reduced or impaired GABA function has also been linked to insomnia and pain symptoms as well. The review goes on to reference research that has demonstrated CBG’s significant antidepressant effects and its ability to regulate blood pressure.
In a GW Pharmaceuticals patent application, researchers referenced by Russo reported on the potential of CBG in the treatment of mood disorders, particularly depression. The applicants cited work that compared the effects of purified CBG sourced from botanical extracts against the known response to imipramine, a tricyclic antidepressant used to treat depression, anxiety, and panic disorder. The study found that moderate doses of CBG were comparable to a standard dose of imipramine, and researchers remarked that CBG may have beneficial effects over other antidepressants in this class which are known to cause many side effects in users.
While scientific evidence has satisfactorily proven the efficacy of THC and THC-like compounds to improve the side effects of cancer treatment, there are costs associated with its use—both literal and figurative. From the possibility of unwanted intoxication to the high cost of pharmaceutical options not covered by most insurance companies to the limited access of regulated and safe THC products across all states, THC-based therapies may not always be the best choice for patients undergoing chemotherapy. But there is much more to cannabis than THC, containing a whole host of pharmacologically active compounds, many of which are gaining research momentum as scientific access to minor cannabinoids increases. With evidence of its efficacy against a variety of cancer types and recent research into the ways it can improve chemo-related side effects, CBG may prove a vital and well-tolerated tool for cancer patients.
This article was updated for clarity February 20th at 4:27PM EST.