Cannabis Science

Does Weed Prevent Cancer?

scientist looking at sample

There is a lot of information floating around the internet about weed and cancer. We know that weed is believed to help cancer patients deal with nausea and appetite loss, among other symptoms. Some stoners believe that taking a hit from their bong can reduce their cancer risk. So can weed prevent cancer? Here’s what we know. 

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Does Smoking Weed Reduce the Risk of Cancer?

People are really interested in weed and its relationship with cancer. First of all, marijuana is not believed to cause cancer, even though there are carcinogens in the smoke.

As a matter of fact, Drug Policy states, “long-term marijuana smoking is not associated with elevated cancer risk, including lung, melanoma, prostate, breast or cervix.”  

So if marijuana isn’t believed to increase cancer risk, how about reducing cancer risk?

There has been some evidence that smoking weed could reduce cancer risk. Before we examine the evidence, remember cancer is pretty complex, and there are so many reasons why some people develop cancers while others don’t. Therefore, some people who use weed may develop cancer anyway. 

A 2021 scoping review and meta-analysis says cannabis use could decrease cancer risk in the United States. 

The review states that weed can reduce your risk of cancer by:

  • Lowering your risk of obesity
  • Lowering your risk of diabetes mellitus (dm)
  • Reducing inflammation 

Let’s look at these claims. 

Lowering Your Risk of Obesity

Stoners are notoriously known for being skinny. However, there is some science behind that. 

Studies show that cannabis users are less likely to be obese than non-stoners. Research published in 2018 concluded that the prevalence of obesity is significantly lower in Cannabis users based on their data. 

So, why does this matter? Well, obesity is often seen as a risk factor for several types of cancers. 

According to the 2021 review, obesity is a risk factor for:

  • Breast
  • Colon
  • Rectum
  • Prostate
  • Esophagus
  • Stomach (cardia)
  • Pancreas 
  • Uterine corpus
  • Gallbladder
  • Kidney
  • Liver
  • Ovary
  • Thyroid

Therefore, if cannabis can reduce your risk of obesity, then technically reduce your risk of these cancers. The 2021 review also said, “Cannabis use protects against nonalcoholic fatty liver disease, a disorder that is strongly associated with obesity and is an independent predictor of gastric and liver cancer, cancer types strongly associated with obesity.”

In addition, the 2021 review says that cannabinoids oppose a shift in our gut biome to one associated with obesity. Apparently, a shift in the ratio of Firmicutes: Bacteroidetes is associated with obesity, but for some reason, weed seems to reduce that shift. 

Again, cancer has many risk factors, and you can’t get any cancer regardless of your weight. 

Lowering Your Risk of Diabetes Mellitus

Weed can prevent cancer by lowering your risk of developing diabetes. The 2021 review says, “Cannabis use is associated with reduced risk of DM, reduced fasting insulin levels, and reduced insulin resistance.” That’s important because diabetes mellitus, C-peptide levels, and insulin resistance are linked to a greater cancer risk. 

In addition to that, diabetes may be linked to faster growth, aggressiveness, and mortality of the following cancers: 

  • Colorectal
  • Pancreatic
  • Liver
  • Postmenopausal breast
  • Endometrial 

While there is some evidence that weed can help prevent diabetes, it can help some diabetics. Healthline says there is evidence that weed can lower blood glucose levels for diabetics. Using weed can also help with weight management and provide other benefits for people who are diabetic. 

However, people who are diabetic still need to approach weed use cautiously. Very Well Health says that weed may double the risk for diabetic ketoacidosis. This condition develops when the body runs out of glucose and uses other sources, such as ketone bodies. However, using ketone bodies make the blood acidic, which makes this a life-threatening condition. 

Reducing Inflammation

Weed having the ability to reduce inflammation is nothing new. Athletes use CBD to reduce their pain and inflammation effectively. 

However, many people don’t know that inflammation can increase cancer risk. The 2021 review said that chronic inflammation is associated with the initiation and progression of cancer. 

Weed helps to reduce inflammation by decreasing obesity and having an effect on certain gene expressions. 

Chronic inflammation is also associated with obesity, which, as we mentioned before, can elevate the risk of some cancers. Weed can decrease Body Mass Index (BMI) by 7%.

In addition to decreasing BMI, weed use is associated with a decrease in pro-inflammatory and an increase in anti-inflammatory gene expression in visceral adipose tissue. In case you’re wondering, visceral adipose tissue is the hormonally active component of total body fat. According to WebMD, visceral fat can cause inflammation. Weed is believed to reduce to prevent or lessen the likelihood of these tissues from releasing proteins that cause inflammation. 

Can Smoking Weed Treat Cancer?

There is evidence that weed could treat certain cancer symptoms or side effects of cancer treatment. According to the American Cancer Society, weed can help relieve nausea and vomiting commonly associated with chemotherapy. Weed may also help with the pain. However, weed alone is not an effective cancer treatment and is not seen as a viable option for treating cancer. says, “While the studies so far have shown that cannabinoids can be safe in treating cancer, they do not show that they help control or cure the disease.”

However, there is promising research that weed fight cancer. According to the 2021 review, “Cannabinoids inhibit tumor initiation, metastasis, vascular adhesiveness, tissue invasiveness, and angiogenesis while selectively stimulating apoptosis of cancer cells.” To be clear, apoptosis is just a fancy word that means cell death. 

Even though the research shows that the American Cancer Society believes that people with cancer should not rely on marijuana while avoiding conventional medicine. They believe it can have serious health consequences. There hasn’t been any proof that weed has cured cancer anyway, so talk to your doctor about cancer treatment options. 


Does weed prevent cancer? There is some evidence that weed could reduce your risk of getting cancer. However, cancer is complicated, and weed alone won’t prevent cancer. There are many ways of other ways you can reduce your risk of cancer. Combine those methods with regular checkups.


About Trevann

Trevann is Stoner Rotation’s Jamaica-based lead writer for the Science section of our cannabis blog. She graduated with honors receiving her Bachelor of Science degree in Molecular Biology from the University of West Indies, Mona. For the last three years, she has covered some of the biggest questions around cannabis and health underpinned with research from supporting studies, medical journals and scholarly articles. Got something on your mind? You can reach her at [email protected].