Cannabis and Cancer
Can CBD Oil Be Effective Against Cancer?
Most existing research mostly focuses on one specific cannabinoid, but an increasing number of scientific studies are revealing how the compounds found together in full-spectrum CBD Oil may destroy cancer cells.
In this article, we present how individual cannabis compounds work separately and which studies examine the combined effects of these compounds. It's important to note that the findings below largely rely on results from cell-line experiments, not human trials. Hopefully, these lab results will pave the way for research in areas where cannabis compounds’ effects on cancer in humans were previously impossible to test.
This article reports many promising results, but we don't want to encourage anyone to deviate from their doctor's recommended treatment!
How Does THC Kill Cancer Cells?
THC (tetrahydrocannabinol) is one of the most well-known psychoactive compounds in cannabis. Full-spectrum CBD oils contain it in amounts below 0.2%, which doesn't cause intoxication but can still exert significant therapeutic effects even at these low concentrations.
THC has several potential therapeutic benefits:
- Pain relief – especially for chronic and neuropathic pain
- Reducing nausea and vomiting – often used in cancer patients undergoing chemotherapy
- Appetite stimulation – for example, in cancer or HIV patients
- Muscle spasm relief – in multiple sclerosis
- Sleep improvement – can help with falling asleep in some people
Until quite recently, almost all cannabis studies and most preclinical research investigating cannabis’s anti-cancer effects focused specifically on THC. Cancer cells – with a few exceptions – have cannabinoid receptors on their surface that THC can bind to, triggering programmed cell death (also called apoptosis) in the cancer cell.
Besides inducing apoptosis upon binding to a cancer cell, THC also helps alleviate pain. It binds to two types of cannabinoid receptors: CB1 and CB2. CB1 receptors are found primarily in the brain and all major organs of the body.
CB2 is the other main receptor type in our bodies to which THC also binds. CB2 receptors are located in the digestive system and the immune system, especially on malignant tumors related to the immune system like leukemia and lymphoma. Many tumors have both CB1 and CB2 receptors.
Interestingly, many highly malignant and metastatic* tumors show elevated cannabinoid receptor levels, making them particularly sensitive to cannabinoids. Both CB1 and/or CB2 receptors need to be present on tumor cells for THC to induce cell death. Another key anti-tumor effect of THC is restricting the formation of new blood vessels needed for tumor growth. Without proper blood flow, the tumor cannot get enough nutrients, which also pushes it towards cell death.
*Metastasis refers to the spread or formation of secondary tumors, when cancer cells break away from their original site, enter the bloodstream or lymphatic system, and establish new tumors in other organs or tissues.
How Does CBD Kill Cancer Cells?
CBD (cannabidiol) is one of the major cannabis compounds and is non-psychoactive. It doesn’t cause intoxication because it does not directly activate the brain’s CB1 receptors. Instead, it acts chiefly by modulating the endocannabinoid system.
Scientifically Supported Therapeutic Effects
Based on current research, CBD has demonstrated proven effects mainly in the following areas:
- Epilepsy – proven to reduce seizures in certain rare and severe forms of childhood epilepsy
- Anxiety reduction – clinical trials show it can ease social anxiety and stress
- Anti-inflammatory and pain-relieving effects – primarily in chronic inflammatory pain
- Improved sleep quality – indirectly by reducing anxiety and pain
- Neuroprotective effects – protection for the nervous system, an active area of research
Although CBD doesn’t directly bind to CB1 or CB2 receptors, it can still have potent anti-cancer effects.
CBD may exert its anti-cancer properties through various mechanisms, the most noteworthy being the suppression of the ID-1 gene.
The ID-1 gene is highly active in newborns and young children, stimulating growth and development of cells, tissues, and organs required early on. In adults, this gene’s activity is minimal or absent as we age. However, cancer cells can reactivate this dormant gene to aid their growth. ID-1 not only promotes cancer cell proliferation but also increases their survival chances. It supports cancer’s ability to metastasize and protects it against some chemotherapy drugs.
Studies have shown that CBD helps “switch off” the ID-1 gene, thereby reducing tumor expression.
Another anti-cancer mechanism of CBD, similar to THC, is inhibiting the growth of new blood vessels that feed tumors. CBD has also been found to prevent cancer cells from adhering to other tissues.
Important: The above findings are not from human studies but from experiments on cell lines. CBD does not replace oncological treatments and should only be used in cancer cases under medical supervision since drug interactions may occur.
THC, CBD, and CBG Combination
Although these cannabinoids individually can exert strong anti-cancer effects, only limited research has been done on their combined effects on cancer. Preliminary studies, however, found that combining THC and CBD can be effective against melanoma skin cancer cells and multiple myeloma cell lines.
Even more promising is a study from St. George’s University of London showing that CBD was nearly twice as potent at destroying leukemia cells from acute lymphocytic and acute promyelocytic leukemia lineages when combined with THC. Combining THC and CBD made the effect twice as strong as using CBD alone.
CBG
The CBG (cannabigerol) is a precursor cannabinoid, from which CBD and THC are enzymatically synthesized.
Like CBD, CBG is non-psychoactive, meaning it has no mind-altering effects. Research suggests it has anti-inflammatory, neuroprotective, and pain-relieving properties.
A 2019 study, also published on the website of the American Biotechnology Center, demonstrated CBG’s anti-cancer activity by showing that, like CBD and THC, it inhibited the growth of colon and rectal cancer cells via programmed cell death.
The previously mentioned study also tested the combination of CBD and CBG (cannabigerol). Their combined use proved stronger than either cannabinoid alone. The CBD and CBG duo was especially effective in acute lymphocytic leukemia and improved outcomes when paired with VINCRISTINE chemotherapy. (In acute promyelocytic leukemia, the CBD+CBG pair together with CYTARABINE KABI induced an opposing effect and negatively influenced tumor treatment.)
The full English study is available here: https://www.spandidos-publications.com/ijo/51/1/369?text=fulltext
It has also been shown that when THC and CBD are combined with chemotherapy, the timing of drug administration critically affects the destruction of cancer cells. More cancer cells died when cannabinoids were administered after chemotherapy rather than before.
It’s important to note that both CBD and THC can influence the metabolism of many chemotherapy drugs! Such drug interactions can increase chemotherapy toxicity by raising drug levels in the blood. Therefore, it’s recommended to stop using CBD oils or other cannabis products 36-48 hours before chemotherapy and resume only 36-48 hours after chemotherapy.
THC + CBD (Sativex®) + Temozolomide: a Phase 2 Trial
Before approval, drugs undergo three testing phases. Phase 2 is the first trial phase conducted on patients with the targeted disease, assessing effectiveness and safety.
GW Pharmaceuticals, based in the UK, developed the world’s first approved cannabis-based medicines, Sativex® and Epidiolex©. Epidiolex is a high-CBD tincture; Sativex contains roughly equal amounts of THC and CBD. As part of the approval process, critical phase 2 studies were conducted on various diseases, including cancer.
One such phase 2 clinical trial combined Sativex® and Temozolomide (a drug for specific brain tumors) to treat recurrent glioblastoma multiforme (GBM), a highly aggressive brain cancer with poor prognosis. While Temozolomide remains one of the best available drugs, it is not very effective alone.
Twenty-one patients with recurrent GBM received 12 daily Sativex® doses plus Temozolomide. Of those treated with Sativex® and Temozolomide, 83% lived at least one year, compared to only 53% in the Temozolomide-only group. The average survival in the Sativex® + Temozolomide group was over 550 days versus 369 days for Temozolomide alone.
Twelve daily doses of Sativex® (maximum dose used in the trial) equate to 32.4 mg THC and 30 mg CBD. It's very encouraging that even at this relatively low dose, a clear positive effect was demonstrated against such an aggressive cancer as GBM. This study highlights the potential benefits of combining cannabinoids with chemotherapy, achieving effects not possible with chemotherapy alone.
CBN
CBN (cannabinol) is a lesser-known cannabis compound formed via oxidation of THC, i.e., when cannabis is exposed to heat and light over time. Unlike THC, it lacks psychoactive effects and is present in relatively small amounts in the plant. Among cannabinoids, it was already recognized in 1975 as potentially anti-cancerous. Since then, only a few publications have focused on it, but a recent study showed that the combination of THC, CBD, CBG, and CBN exhibits the most potent anti-cancer effects against estrogen-positive breast cancer cells.
(CBN is often used to treat sleep disorders due to its strong sedative effect. It may also have anti-inflammatory, pain-relieving, and appetite-stimulating properties.)
CBC (Cannabichromene)
CBC, like THC and CBD, belongs to the cannabinoid group found in the cannabis plant. It’s one of the lesser-known, non-psychoactive cannabinoids, meaning it does not cause mind-altering effects. Research shows that beyond its anti-cancer properties, CBC may possess various health benefits.
A 2021 Israeli study found that when CBC was combined with CBD or THC, it led to “cell cycle arrest and cell death” against bladder urothelial carcinoma (UC), the most common cancer of the urinary tract. CBC combined with THC or CBD also inhibited cell migration (metastasis).
Another Israeli publication reported that the most effective cannabinoid combination to destroy ovarian cancer cells combined THC, CBG, and CBC.
(While these studies are promising, incorporating larger quantities of CBC into full-spectrum cannabis products poses challenges since CBC is present only in very low amounts in the cannabis plant.)
Other Promising Cannabinoids in CBD Oil
Israeli researchers have also identified many cannabinoids present in smaller amounts in the cannabis plant as potentially anti-cancerous. The two most studied cannabinoids of this type—found only in trace amounts in the plant—are tetrahydrocannabivarin (THCV) and cannabidivarin (CBDV).
Acidic or Raw Cannabinoids
Acidic cannabinoids, such as CBDA, THCA, and CBGA, are abundantly found in freshly harvested, standing cannabis plants. Heat and UV light transform these into their better-known forms, like CBD, THC, and CBG. The less UV light exposure and heating during drying and extraction, the more raw cannabinoids are preserved in the final product.
Why Is It Beneficial to Have Them in the End Product?
Acidic cannabinoids enhance the effects of other cannabis compounds and can be effective on their own. A 2016 study found that THCA inhibited growth in two different human breast cancer cell lines: HER2-positive and triple-negative, the latter being the most resistant to conventional therapies.
Israeli researcher Dedi Meri discovered that on certain prostate cancer cell lines, THCA produced the strongest anti-cancer effect among all cannabinoids.
Two Japanese studies investigating cannabidiolic acid (CBDA) in breast cancer cell lines showed that CBDA can limit the metastatic potential of tumor cells. Researchers estimate this applies to roughly 40% of breast cancer types.
Preclinical studies have shown that cannabis extracts high in CBDA and CBGA inhibit aldose reductase, an enzyme involved in inflammation and cancer growth.
It has also been found that CBGA and THCA independently exert anti-cancer effects against precancerous adenomatous polyps and colon cancer cells. When applied together, their anti-cancer effects are even stronger.
Patent for Developing a Combined CBGA and CBDA Cancer Drug
In 2018, GW Pharmaceuticals (developers of Epidiolex© and Sativex©) received a patent from the United States Patent and Trademark Office for using CBGA and CBDA in cancer treatment. This suggests they hold independent, patented research confirming the effectiveness of these two compounds as potential anti-cancer agents. Notably, the patent emphasizes cannabinoids are more effective when used in combination rather than alone. The patent states:
"This invention relates to an active ingredient containing cannabidiol (CBD) and another cannabinoid potentially including cannabigerol (CBG), cannabigerolic acid (CBGA), cannabidiolic acid (CBDA), and tetrahydrocannabivarin (THCV) for pharmaceutical use, specifically for treating cancer. These combinations have demonstrated synergistic effects in treating one or more of the following cancer types: breast cancer; liver cancer; lung cancer; pancreatic cancer; melanoma; ovarian cancer; stomach cancer; kidney cancer; or bladder cancer. Two particularly noteworthy active ingredient combinations are cannabidiol (CBD) and cannabigerol (CBG); and cannabidiolic acid (CBDA) and tetrahydrocannabivarin (THCV)."
Terpenes
Cannabis terpenes are aromatic compounds produced by the cannabis plant. Many of these are also found in other plants. They serve various roles in the plant’s life, including deterring predators or responding to environmental stress. Terpenes also give cannabis its distinctive aroma and flavor.
Some well-known cannabis terpenes include:
Myrcene: Found in most cannabis strains. It has a spicy, earthy, and fruity aroma.
Limonene: Responsible for the citrus scent and flavor of lemon and orange. It has a light, fresh smell and may improve mood.
Pinene: Gives the aroma typical of coniferous trees. Two main types: alpha-pinene (fresh pine scent) and beta-pinene (slightly fruity).
Caryophyllene: Spicy, clove-like scent terpene. Interestingly, it can bind to CB2 endocannabinoid receptors, providing effects similar to phytocannabinoids like CBD, CBG, CBC, and THC.
Terpenes substantially influence the therapeutic effects of cannabis.
Over 200 terpenes have been identified in cannabis, several of which show anti-cancer activity. In a brilliant review on cannabis pharmacology, Dr. Ethan Russo and colleagues reported the anti-cancer effects of limonene, ɑ-terpineol, linalool, camphene, ɑ-caryophyllene, β-elemene, guaiol, and eudesmol terpenes.
Can Cannabis Oil Be Used During Chemotherapy?
Yes, cannabis oil (CBD Oil) can be used during chemotherapy but only under medical supervision. CBD-containing products are suitable for easing chemotherapy side effects such as nausea, pain, loss of appetite, anxiety, or improving sleep quality. However, timing is important since CBD and other cannabinoids can affect liver enzymes involved in metabolizing chemotherapy drugs, potentially slowing or accelerating their breakdown.
Drug interactions: CBD can influence the metabolism of certain drugs by inhibiting the CYP450 enzyme family in the liver, which may alter chemotherapy effectiveness. As mentioned earlier, it’s advised to start using CBD-rich products 36-48 hours after chemotherapy and stop them 36-48 hours before chemotherapy.
Therefore, cannabis oil use during chemotherapy can help alleviate side effects but must always be guided by a professional, especially due to potential drug interactions. Always consult your oncologist and a physician experienced in cannabis-based therapies before using cannabis oil!
Can Cannabis Oil Be Used During Immunotherapy?
Immunotherapy is a treatment method that harnesses the immune system to treat various conditions, such as cancer, allergies, autoimmune diseases, or infections. Its goal is to enhance, modify, or restore the immune system's natural ability to combat diseases. Immunotherapy has revolutionized treatment for many diseases, especially in oncology, and is one of the fastest-growing fields in medical research.
Using cannabis oil during immunotherapy generally requires caution because active compounds in cannabis, particularly THC (tetrahydrocannabinol) and CBD (cannabidiol), can affect immune function. It was previously thought that CBD oil might reduce immunotherapy’s effectiveness, which aims to boost the body's natural immune response against cancer cells, but a recent, larger-scale study has shed new light on this issue.
The study examined 201 non-small cell lung cancer patients undergoing immunotherapy (checkpoint inhibitor treatment). Half the group used cannabis within the first month, while the other half did not. Comparing results, they found no difference in overall survival or disease progression.
The study was supplemented with animal experiments. Mice were treated with different combinations: only immunotherapy, only cannabis, both combined, or none. The outcome?
Cannabis did not reduce immunotherapy effectiveness. In fact, mice receiving only cannabis showed slightly slower tumor growth compared to controls.
Researchers concluded clearly that cannabis – and likely CBD Oil – does not diminish immunotherapy benefits in non-small cell lung cancer.
This doesn’t guarantee the same across all cancer types and therapies but is reassuring for those worried CBD oil might interfere with treatment.
Can CBD Oil Be Used During Radiation Therapy?
Radiation therapy is a cancer treatment that uses high-energy radiation (usually X-rays or gamma rays) to destroy cancer cells or stop their growth.
In brief:
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Radiation damages the DNA of cancer cells
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Cancer cells have a reduced ability to regenerate compared to healthy cells
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Treatment is targeted to spare surrounding healthy tissue
When is it used?
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As a standalone treatment
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Before surgery (to shrink the tumor)
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After surgery (to eliminate remaining cancer cells)
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Combined with chemotherapy
How is it administered?
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In multiple sessions over weeks
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The radiation itself is painless
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Side effects depend on the treated area (e.g., fatigue, skin irritation)
Is CBD Oil Usable?
According to current science, CBD (cannabidiol) may theoretically be used during radiation therapy but not as an “anti-cancer treatment”, only at most for symptomatic/supportive purposes, and with medical consultation.
Possible Benefits
Pain relief
Cannabis, especially THC (tetrahydrocannabinol) and CBD (cannabidiol), can help manage pain, a common side effect of radiation therapy.
Reduction of nausea and vomiting
Radiation, especially near tumors in the digestive tract, can cause severe nausea.
(Dronabinol (synthetic THC) and Nabilone, both cannabis derivatives, are FDA-approved for chemotherapy and radiation-induced nausea treatment.
Appetite stimulation
THC's well-known appetite-stimulating effect can be beneficial for those experiencing loss of appetite during radiation.
Support for anxiety and sleep
Many patients undergoing radiation experience anxiety and sleep disturbances. CBD, THC, and the CBN found in quality cannabis oils may aid relaxation and improve sleep quality.
Always consult your oncologist before using cannabis oil during radiation therapy!
Can CBD Oil Be Used During Hormone Therapy?
In cancer cases, hormone therapy refers to drug treatments that don't directly kill cancer cells but rather reduce or block hormones’ tumor-promoting effects.
Certain cancers – especially breast cancer, prostate cancer, and less commonly uterine cancer – are hormone-dependent, meaning cancer cells proliferate faster in response to hormones present in the body (e.g., estrogen, testosterone).
Hormone therapy aims to:
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reduce hormone production (e.g., lowering estrogen or testosterone levels),
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block hormone effects on cancer cells,
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or inhibit hormone receptor function.
Examples include:
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aromatase inhibitors (e.g., Letrozole) – reduce estrogen production,
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estrogen receptor blockers (e.g., tamoxifen),
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androgen deprivation therapy in prostate cancer.
It’s important to know that hormone therapy is a long-term treatment, often lasting years, and is not chemotherapy: it works slower but is targeted, although can have side effects since it affects the entire hormonal system.
Can CBD Be Used?
Based on current evidence, it cannot be conclusively stated that using CBD Oil during hormone therapy is prohibited.
However, CBD can affect liver enzymes (CYP3A4, CYP2C19) that many hormone medications rely on for metabolism.
No large, specific human studies on hormone therapy combined with CBD exist yet, so caution is needed.
The safest approach is to consult a doctor, start with a low dose, increase gradually, and monitor for side effects when using CBD Oil.
When NOT to Use Together?
- In cases of liver disease
- When taking multiple drugs metabolized by CYP3A4 liver enzymes (e.g., certain antidepressants, steroids, blood pressure medications)
Which CBD Oil Is Best for Cancer?
There are two main types of CBD or cannabis oils: broad-spectrum and full-spectrum. Both contain other beneficial cannabinoids besides CBD, but broad-spectrum products contain no THC.
From available research, one can infer that cannabis oils containing THC—i.e., full-spectrum products—may be more effective for cancer.
There is wide variability among full-spectrum products on the market, so exercise caution when ordering cannabis oil.
How Should I Dose Cannabis Oil for Cancer?
Finding the right dose and consistent use is key to success! It’s generally recommended that a large amount of cannabis oil is required for cancer cases, gradually built up so the body can get used to cannabis compounds, especially THC.
Start with a low dose and slowly increase until the body still tolerates the oil well.
How do I know if the daily dose is enough?
If you experience excessive fatigue, lethargy, or conversely, excessive alertness or, in rare cases, diarrhea, reduce the daily dose!
For detailed guidance on cannabis oil dosing, visit: https://www.cannadolcbd.eu/hu/cbd-adagolasi-utmutato
Important:
This content summarizes key research on the anti-cancer effects of cannabis compounds. Most studies were conducted on cell lines.
Cell lines are cells isolated and maintained under laboratory conditions and used in scientific research, for example, cancer studies or drug development. These cell lines may originate from original tumors or other sources and are typically able to proliferate indefinitely and remain genetically stable for the tumor type of origin.
Their use offers numerous advantages in cancer research and drug development:
Reproducibility: Cell lines can be easily cultured and maintained under laboratory conditions, enabling many experiments to be performed.
Consistency: Uniform cell lines allow repeatability of experiments and comparison of results.
Controlled conditions: Cell lines can be treated under regulated conditions adjustable during experiments.
Genetic stability: Lines derived from the same cell type share similar genetic characteristics.
These lines are often used to study tumor biology, drug effects, and cancer progression. It’s important to understand that although cell lines are useful and informative, lab results require further studies and clinical trials before clinical application.
Although using various cannabis compounds can offer many benefits, we do not encourage anyone to deviate from their doctor’s prescribed treatment!
References:
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- https://link.springer.com/article/10.1007/s11418-016-1030-0
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