is pot bad for your liver


If you’ve been reading up on cannabis science, you’ve probably seen lots of references to how cannabis is a much healthier alternative to certain pharmaceutical options that can negatively impact your liver.

All kinds of medications can build up in your liver and cause health problems later on, even over-the-counter pills like aspirin. But few people discuss whether cannabis in any form may have an impact on our livers as well.

Are Cannabis Edibles Bad for Your Liver?

Cannabis consumers may be especially interested in how cannabis edibles may affect liver health. Are they OK to consume? Or, because the liver is key to digesting food, do marijuana edibles overwork the liver even more, making edibles a less-than-healthy choice for everyone?

When it comes to the science of cannabis and livers, we unfortunately have very little data to work with. Few studies have addressed liver-related issues and cannabis, and those that have were mostly rodent studies and not direct studies on humans. Still, these studies, while limited, provide valuable insight into the ways cannabis may affect your liver.

To get a better idea of cannabis and its impact on liver health, we spoke with HelloMD’s Chief Medical Officer Dr. Patricia Frye to learn more about how to approach liver health as a cannabis consumer.

When it comes to cannabis edibles, Dr. Frye points out the lack of studies on this specific question. She also notes that she isn’t “aware of any data that suggests that edibles are hepatotoxic,” or in other words, damaging to liver cells.

She also points to the lack of studies on how cannabis—in any form—affects healthy livers. Most of the studies on cannabis and liver health have been designed to look at how cannabis affects folks with liver conditions or health issues that may impact the liver.

So, while we have some data for those with liver issues, for folks with healthy livers, it’s especially challenging to say how cannabis may affect their liver health. There just haven’t been any studies that look at this issue in healthy people.

In some ways, no news is good news. With so many cannabis consumers, it seems likely that medical professionals would have noticed liver issues in folks who take marijuana by now. But it’s always possible that long-term effects have gone unnoticed or have been attributed to other causes. We need more research on human models to really answer the question.

How Marijuana May Benefit Liver Health

While we don’t have much data on cannabis’s effect on healthy livers, we do have some data regarding livers that are already compromised by some type of issue.

And it does seem like there may be benefits to consuming cannabis for certain liver conditions, such as:

  • Chronic hepatitis C
  • HIV
  • Alcoholic and nonalcoholic fatty liver disease
  • Hepatic fibrosis
  • Hepatic encephalopathy
  • Psychosis-related steatosis

When it comes to the research we do have, Dr. Frye says that “CB2 activation and blocking CB1 receptors in the liver may be hepatoprotective—decreasing fibrosis, inflammation and promoting hepatocyte survival and regeneration.” This could mean that cannabinoids which activate the endocannabinoid receptor CB2 but block the CB1 receptor are actually helpful for liver health.

As Dr. Frye explains it, “Hepatic CB1 receptors upregulate hepatic fatty acid production and promote liver fibrosis.” On the other hand, “CB2 receptors can suppress fatty liver disease and protect the liver from damage caused by decreased oxygen delivery.”

With CB2 activation people see decreased:

  • Hepatic inflammation
  • Oxidative stress
  • Fibrogenesis So, activating CB2 receptors in the liver and blocking the liver’s CB1 receptors could be key for helping to address certain liver conditions.

Still, cannabis’s effect on the liver depends greatly on the exact liver condition someone has. For example, Dr. Frye points out that “in patients with hepatitis C, the antiviral effect may be of some benefit. But this does not apply to hepatitis B.” For other conditions, cannabis seems to offer the liver some protection from damage.

Also, among alcohol users, for example, individuals who also consume cannabis showed significantly lower odds of progressing through the stages the alcoholic liver disease and developing:

  • Steatosis
  • Steatohepatitis
  • Fibrosis
  • Cirrhosis
  • Hepatocellular carcinoma

And the data suggests that cannabidiol (CBD) may offer even more protection from nonalcoholic fatty liver disease (NAFLD). According to Dr. Frye, one German study even showed 20% reduced prevalence of NAFLD in patients who took cannabis. These cannabis consumers also saw reduced rates of obesity and diabetes, which are commonly associated with NAFLD.

And a new study on cannabis and liver health demonstrated that cannabis can play yet another a protective role, helping protect the liver in patients suffering from psychosis.

The study looked specifically at liver health for patients suffering from psychosis and found cannabis consumption was associated with a lower risk of liver steatosis in psychosis. Scientists aren’t sure if this protective effect has to do with cannabis’s metabolic effects on weight gain or if marijuana’s positively affecting liver tissue directly, but cannabis certainly seems to be beneficial.

How Cannabis May Be Risky for Liver Health

It’s clear that cannabis can be helpful for certain liver conditions, but it could it also be harmful? As it turns out, there’s some evidence that cannabis may pose risks for your liver as well.

When it comes to taking cannabis for your liver, Dr. Frye warns that “heavy use may exacerbate end-stage cirrhosis.” So if you have this condition, you may want to avoid consuming much cannabis.

Those with chronic hepatitis C may also want to be cautious, despite the beneficial antiviral effects cannabis may have.

A 2008 study showed that daily cannabis consumers had higher incidence of fatty liver associated with chronic hepatitis C. Still, Dr. Frye points out that it’s “not clear if there is cause and effect.” It’s impossible to tell from the study whether those patients were simply more symptomatic, and so consumed more cannabis to address their symptoms or if cannabis was actually causing the fatty liver disease.

There’s also some worry after a study in which high doses of CBD given to mice led to the death of some of the subjects involved. The researchers concluded the mice died from liver issues because they had elevated liver enzymes and increased liver size.

Still, other researchers have noted issues with this research. For one thing, the dose was incredibly high—more than most humans would ever ingest and 100 times higher than the maximum recommended dose for Epidiolex, the only FDA-approved CBD-based medicine.

The CBD administered to the mice was also extracted using hexane—a solvent with known neurotoxic properties. So it’s unclear whether the hexane could have been a factor in the mice death.

In addition, the test was on a very small sample size—only six mice. And the researchers reported that 75% of the subjects died. But as critics have pointed out, this would mean that four and a half mice would have died, a true impossibility. Errors like this should certainly lead people to question the truth of the rest of the data in this study.

Still, testing of Epidiolex also found elevated liver enzymes in human subjects, too. So, we shouldn’t simply ignore this data. But we should take it with a grain of salt and balance it against the data showing CBD can be helpful for the liver in other studies.

If you’re concerned about your own liver health with cannabis, it’s best to talk to a doctor familiar with cannabis who can help you to figure out whether the plant—and in what form—is right for your situation.

Photo credit: VDB Photos/

If you’re new to cannabis and want to learn more, take a look at our Cannabis 101 index of articles. And if you have questions about cannabis, ask them and our community will answer.

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Are you harming your liver by eating marijuana edibles? The studies are scarce, but it seems there are pros and cons around cannabis and liver health.

Weed Seems to Protect Your Liver From the Effects of Hard Drinking

In January, the California Department of Alcoholic Beverage Control issued new rules declaring that intoxicating drinks cannot be infused with marijuana. Of course, that isn’t going to stop many people from simultaneously consuming weed and booze, especially as more states like California roll back cannabis prohibition.

These people might be interested to hear about a string of recent studies suggesting that cannabis can actually have protective benefits for the liver. Still, they should resist the urge to start slamming shots after taking a dab, or vice versa.

The largest study of the bunch found that drinkers who smoke weed had significantly lower odds of developing liver diseases including hepatitis, cirrhosis, steatosis, and even hepatocellular carcinoma, a type of liver cancer. Researchers at the National Institute of Scientific Research at the University of Quebec looked at the discharge records of nearly 320,000 patients who had a past or current history of abusive alcohol use.

“We found that if people are using cannabis in the dependent manner, they actually are much more protected from alcoholic liver disease,” Terence Bukong, a hepatologist and the study’s lead investigator, tells Tonic.

Alcohol abusers who didn’t use weed had about a 90 percent chance of developing liver disease, whereas light cannabis-using heavy drinkers had about an 8 percent chance. For dependent cannabis users who drink a lot, there was only a 1.36 percent chance. In other words, this study suggests that heavy pot use could mean a better defense against alcohol-related disease compared to light or no marijuana use.

This was a population-based correlation study, so it’s too early to draw strict conclusions. However, it’s consistent with another paper published in October, which looked at more than 8,200 patient records and found that the “lowest prevalence of [non-alcoholic fatty liver disease] was noted in current heavy users of marijuana.” (Some of the participants in this study did drink, but the data was adjusted to account for that.) They also found that cannabis users had worse diets than non-smokers—they consumed more calories, soda, and alcohol—yet they were less likely to be obese.

The researchers, led by a team at the Stanford University School of Medicine, hypothesize this might be related to the link between marijuana use and lower fasting-insulin levels, which could also protect the liver from non-alcoholic liver disease. Liver disease is frequently associated with insulin resistance and is caused when the liver accumulates too much fat, thus impairing glucose metabolism. So, cannabis may protect the liver even from dietary risks.

Watch More from Tonic:

The anti-inflammatory properties of cannabis are well established. Your body has an endocannabinoid system, which influences memory, appetite, and immune function. The two best-known endocannabinoid receptors are CB-1 and CB-2, which are found throughout the body, including the liver, where they play an important role in the development of liver diseases. (CB-1 seems to promote liver damage while CB-2 seems to protect against it.)

The liver also metabolizes cannabis to differing degrees depending on how it’s ingested. And the therapeutic effects of marijuana are highly dependent on the ratio of two main ingredients: tetrahydrocannabinol (THC) and cannabidiol (CBD). Researchers had no way of determining this ratio or even the strain type with the data available, so they don’t know to what extent the receptors in the liver would have been activated.

“The principle is creating a balance between the CB-1 and CB-2 agonism,” Bukong says. “How do we create a balance where cannabis use is actually having a therapeutic effect against detrimental effects?…I don’t have an exact mechanism for how that balance is happening.”

On the other hand, drinking has some health benefits, but only in moderation. The minute alcohol hits your bloodstream, it triggers an immune response, binding to receptors on immune cells, sparking the release of inflammatory proteins called interleukins.

Interleukins are a class of molecules called cytokines that are used in cellular signaling. In this case, they cause a cascade of inflammation when specialized white blood cells in the liver encounter toxins released by bacterial cells. Alcohol abuse makes your intestinal barrier more permeable, which allows these bacterial toxins to seep throughout the body.

“If you drink alcohol in an abusive manner, either binge drinking or chronic, excessive drinking, there is a possibility of you creating a leaky gut,” Bukong explains. “The bacteria transfers from your gut into the hepatic portal vein and then into the liver.” The liver then recognizes these pathogens and begins to produce inflammatory cytokines, he says.

The more often this happens, the more inflammation there is, which can cause a type of scarring called fibrosis. Too much scarring and you get cirrhosis, a hardening of the soft hepatic tissue, which can lead to life-threatening liver failure. Cirrhosis and hepatitis B are both leading risk factors for types of liver cancer. So you really don’t want inflammation in your liver.

Cytokines can help us measure how much damage alcohol does to the gut, liver, brain, and other organs, plus they are useful biomarkers for detecting alcohol use disorders. In a study published in December, researchers at the University of Colorado Boulder measured interleukin levels in 66 people who drink, some of whom used marijuana. They found that those who use cannabis had less circulating cytokines, which “suggests that cannabinoids may also have the potential to reduce alcohol-related harm.”

“There’ve been disassociation studies—correlational studies with people who drink having greater pro-inflammatory proteins in their blood versus people that don’t. And then also people who smoke [weed] who tend to have lower inflammatory levels [versus] people who don’t,” Raeghan Mueller, a molecular biologist at the University of Colorado Boulder, and one of the study’s co-authors, explains. “So it’s just one of those things that we just thought, ‘Okay, let’s try it out and see if we see anything,’ and we did, so that was exciting.”

The University of Colorado study was a small one, but it tells us which inflammatory markers researchers should look for when researching cannabis and alcohol use. In the future, science needs to look at pot’s interaction with the liver at the cellular level. It also needs to explore the ratio of THC to CBD, which can vary significantly across different cannabis strains.

“I think that we need to go further and know exactly what is the detailed molecular mechanisms and also what are the potential side effects,” Bukong says, advising that this research should be taken with caution. “It’s a bit premature to make conclusions based on just preliminary data, but we will know more in the next couple of years.”

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Marijuana FTW.