CBD for cancer: Everything you need to know

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The majority of the available evidence suggests that CBD and cannabis therapies may complement cancer treatment. CBD may help people with cancer by:

Stimulating appetite

Many people who are having cancer treatment experience nausea and loss of appetite, issues that can make it difficult to maintain a healthy weight.

Ingesting a cannabis product that delivers THC to the bloodstream may help stimulate the appetite. There is no evidence, however, that CBD alone has this effect.

Relieving pain

Both cancer and its treatment can lead to pain. Cancer often causes pain due to inflammation, pressure on internal organs, or nerve injury. When the pain is severe, it can become resistant to opioids, which are powerful pain relief medications.

CBD acts indirectly on the CB2 receptors, which may provide widespread pain relief by reducing inflammation. THC acts on the CB1 receptors, which may help with pain that results from nerve damage.

Easing nausea

Cannabis may help people with cancer who experience regular nausea and vomiting, especially when this stems from chemotherapy.

However, the antinausea effect appears to come from the THC, not the CBD, in the plant. Anyone looking to try cannabis to reduce nausea should prepare for the psychoactive effects of THC in prescribed cannabis products and discuss them beforehand with a doctor.

Many people find relief from low doses of THC. Prescription versions of synthetic THC that have fewer side effects are also available.

Some people wonder whether cannabis or CBD might help prevent cancer. The National Cancer Institute (NCI) has reviewed numerous investigations into cannabis and cancer, and it has found mixed results.

An older study of 64,855 people in the United States found that cannabis use did not increase the risk of tobacco-related cancers. However, this study also found that men who used cannabis but never smoked tobacco had an increased risk of prostate cancer.

On the other hand, the authors of a 2015 study in men found a promising relationship between cannabis and bladder cancer. After adjusting for several factors, they found that participants who used cannabis had a 45% lower risk of developing bladder cancer.

While research has shown that cannabis smoke produces carcinogens, the link between inhaled cannabis and cancer remains inconclusive.

Meanwhile, ingesting CBD extract does not expose the body to the same carcinogens as smoking cannabis. More long-term studies in humans are necessary to determine what role, if any, CBD has in preventing cancer.

No large clinical trials are currently investigating the use of cannabis or cannabinoids, such as CBD, as a cancer treatment. There are small pilot studies, including an investigation into the use of THC and CBD in combination with chemotherapy as a treatment for a type of brain cancer. However, the research is still in its early stages.

In 2016, scientists concluded that cannabinoids show promise in the fight against cancer after determining that these compounds inhibited the growth of many types of tumor cell in test tube and animal models.

However, they also noted that some dosages and types of cannabinoid might suppress the immune system, allowing tumors to grow unchecked.

Overall, determining whether cannabinoids can combat cancer will require much more research.

The cannabinoid receptors in the brain do not act like many other drug receptors. For this reason, using CBD, for example, may involve a lower risk of side effects than using a medication.

Also, there are no apparent lethal doses of CBD or THC, which is not true for traditional pain management medications. This is because cannabis does not affect respiration function in the central nervous system like opiates do.

It is worth noting, though, that the body has widespread cannabinoid receptors. This is why CBD affects not only the brain, but also many other organs and tissues.

Small-scale studies have found that people generally tolerate CBD well, but some people may experience mild side effects, including:

• fatigue
• diarrhea
• changes in appetite
• changes in weight

CBD can also interact with a range of medications and cause liver damage. These medications include:

• antibiotics
• antidepressants
• antianxiety medications
• anti-seizure medications
• blood thinners
• chemotherapy drugs
• muscle relaxers
• sedatives, or sleep aids

CBD products can also interact with some over-the-counter aids and supplements, so it may be a good idea to speak with a doctor before trying them.

Also, people should exercise caution when taking CBD alongside prescription medications that warn about possible interactions with grapefruit.

In addition, increased liver toxicity is a possible side effect of CBD. In one 2019 study, researchers administered varying doses of CBD to mice. The mice had that received higher doses experienced liver damage within 1 day.

Some people might be concerned about the possibility of becoming dependent on CBD. Clinical trials of Epidiolex, the CBD product that the Food and Drug Administration (FDA) has approved to treat epilepsy, found no indications of physical dependence. The manufacturers of Epidiolex do warn about the potential for liver problems in the product’s safety information.

Finally, as the NCI notes, CBD inhibits specific enzymes that may be important for cancer therapies. Cancer treatments that rely on these enzymes could be less effective in people who take CBD.

While CBD appears to help ease some cancer symptoms and side effects of treatment, no research suggests that CBD can combat cancer itself. And as the NCI points out, taking CBD may actually inhibit certain cancer treatments.

As with any new supplement, speak with a doctor before using CBD during cancer treatment to ensure that it will not cause interactions.

Is CBD legal?The 2018 Farm Bill removed hemp from the legal definition of marijuana in the Controlled Substances Act. This made some hemp-derived CBD products with less than 0.3% THC federally legal. However, CBD products containing more than 0.3% THC still fall under the legal definition of marijuana, making them federally illegal but legal under some state laws. Be sure to check state laws, especially when traveling. Also, keep in mind that the FDA has not approved nonprescription CBD products, and some products may be inaccurately labeled.