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CBD vs THC for Cancer? The Answer May Surprise You

Randy Robinson
Tumor on neck

Cancer is a beast that hides and moves incognito. Cannabis medicine has shown promise in both rooting out and killing cancer. But, the debate continues: CBD vs THC for cancer?

When reading blogs, news stories, or scientific papers about cannabis and cancer, things can get pretty confusing pretty quickly. There is this push and pull of CBD vs THC for cancer treatment. Why is CBD heralded as the medicinal component of  cannabis while THC is portrayed in the media as the chemical that just gets us high? And why is THC the only cannabinoid attributed to killing cancer cells, (according to RSO fanatics), when CBD also has a role?

Cancer Cell Animation

Image Credit: CI Photo

In this post on endometrial cancer, I mentioned a study that found THC did nothing for endometrial cancer cells, but a combination of CBD and anandamide (an endocannabinoid) appeared to kill the cells.

Yet a few weeks ago, I wrote another post where Manuel Guzman, Ph.D, saw brain and breast tumors shrink after injecting THC into the cells.

What gives? Is it THC or CBD that fights cancer? Is it both? And if it’s both, should one be given at higher amounts than the other? Or does it depend on the type of cancer?

THC vs CBD Chemical formula

Image Credit: Shutterstock

The short answer is: it probably depends.

The science for phytocannabinoids, like CBD vs THC for cancer, has been seriously impeded due to prohibition. Governments around the world tightly restrict cannabis-related research in human subjects.

What Do The Latest Studies Tell Us?

However, we have some clues. In the case of Guzman’s THC injections into glioblastoma brain tumors, THC may have shrunk the tumors because THC readily binds to and activates CB1 receptors. CB1 receptors are primarily located in the brain and spinal cord. Since glioblastoma cells come from brain cells, it makes sense that THC could kill brain cancer cells.

animation of endometrial cancer

Image Credit: Lightspring

Other tissues, such as endometrial tissue, should exhibit less CB1 expression and more CB2 expression. CB2 receptors are typically found in immune cells and lymphatic cells. The lymphatic system is closely connected to the endometrium, and researchers believe that lymphatic issues cause endometriosis, a condition where endometrial tissue grows outside of its native uterus.

It’s possible that because lymphatic function directs endometrium behavior, then endometrial cancers would respond better to CBD rather than THC. That may be due to CBD’s tendency to bind or “stick” to CB2 receptors rather than CB1. And this is exactly what we saw in the TRPV1 study for endometrial cancer: CBD and anandamide killed endometrial cancer cells in vitro, whereas THC did nothing to those same cells.

The truth is, cancer is one complicated beast that is hard to kill. No single formula will work for all cancer types, and here’s why:

Cancer Isn’t One Thing So One Medicine Won’t Do It

To understand why some cancers respond to THC and others to CBD, we need to know how complex cancer really is. One of the great misconceptions about cancer is that it’s one thing. That’s because we use one word (cancer) to describe a specific disease state that causes our cells to reproduce uncontrollably. As my mentor Robert Melamede, PhD. used to say, “Cancer happens when our cells forget to die.”

Child with cancer smiling

Image Credit: Fran Tab

Melamede’s slogan is helpful for the layperson to understand cancer, though it’s incomplete. Cancer does occur when our cells begin multiplying in a haphazard fashion. However, if our cells simply forgot how to die, we’d actually become immortal as the cancer advanced.

Instead of simply forgetting how to die, think of cancer cells as rogue parasites, like little cellular terrorists that ignore the rules obeyed by normal cells.

One of these rules concerns programmed cell death. In programmed cell death, the cell’s DNA keeps track of how many times a cell line has divided or reproduced. After the cell divides so many times, the cell dies off forever, to prevent aged DNA from compromising the rest of the body. Programmed cell death is the reason we all grow old and eventually die, despite our best resistance.

Apoptosis Animation

Image Credit: Kateryna Kon

Cancer cells lose their internal clock. They don’t keep track of how many times they’ve divided. They’ve hacked their own code, basically.

The other rule ignored by cancer cells is contact inhibition. Normal cells recognize when they’ve reached their capacity: if too many of a particular cell are produced, your heart tissue may malfunction or your skull may place too much pressure on your fragile brain. Cells know when they’ve hit the limit, and they’ll stop dividing once they are contacted on all sides, so there is no cell pile-up.

Cancer cells, as you’ve probably guessed, don’t care about contact inhibition. They’ll keep piling up until they kill their “host.”

Tumor on neck

Image Credit: Gabor Kenyeres

One last rule violation is angiogenesis. Cells normally generate new blood vessels through the vascular network as we grow and mature. However, tumors can grow their own blood vessels to supply themselves with massive amounts of glucose, stealing this precious energy source from healthy cells while helping the cancer cells proliferate unchecked. Cancerous angiogenesis also helps the cancer to spread to other parts of the body through blood and lymphatic vessels, a process known as metastasis.

These three serious rule violations add up to a deadly situation. This situation is what we call cancer. And it’s complicated to treat.

Vascularization of malignant tumor. Image Credit: Jubal Harshaw

So, CBD vs THC for Cancer Treatment?

The answer is both and we don’t know which will kill each type of cancer cell. Yet.

Many studies have shown that THC kills cancer cells and CBD prevents metastasis. Of course, it is far more complicated than this. Prostate cancer, for example, can be suppressed by cannabinoids through the ability of these to limit male sex hormones.

In another study, Californian scientists found that CBD inhibited breast cancer metastasis in mice, and further research discovered that CBD is the first outside agent that is capable of regulating Id-1 in human breast cancer cells, effectively stopping its growth and spread. This was groundbreaking work for breast cancer!

For lung cancer, THC has been found to expose the existence of cancer by inducing the expression of a special protein called ICAM-1 and this effectively calls the immune system over to get rid of it. It’s like Big Brutus as the local diner rings the dinner bell and yells, “Come and get it!”

CBD vs THC for cancer may be the exact wrong debate to have. It’s likely a more complicated Entourage Effect or a combination that effectively does the trick.




Randy Robinson

As someone who wanted to know everything but couldn't decide on anything, Randy completed degrees in English, World History, and Molecular Biology. During their studies, they received an externship at the biotech firm Cannabis Science Inc., focusing on phytocannabinoids as anti-tumor and anti-cancer agents. Based in the Mile High City of Denver, Colorado, you can find Randy on Twitter, Instagram, and Medium @RanDieselJay

  • Avatar
    Judy loew

    Is it cannabis CBD or hemp ?

    February 10, 2019 at 8:59 am Reply
    • Jennifer Grant

      We’d have to technically say “Marijuana” as hemp is a type of cannabis.

      February 10, 2019 at 9:42 pm Reply

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