How Cannabis Affects Your Liver
Research on how cannabis affects the human liver is still quite limited, but from the studies that have been done, we know that the relationship between the two can be somewhat complicated and can vary depending on the liver condition involved.
For most healthy individuals, cannabis use shouldn’t cause liver complications and may even potentially play a protective role against developing alcoholic liver disease and nonalcoholic fatty liver disease.
For those with more severe liver conditions, however, or those who are taking other medications, care should be taken to ensure that you are helping and not hurting your liver.
Although medicine still has many questions on medical marijuana and the liver, here is what science can tell us.
How cannabis interacts with the liver
To understand the effects of cannabis on the liver, we have to start with an explanation of how the liver is affected by the endocannabinoid system (ECS). The ECS modulates many of the human body’s most crucial functions — like sleep, energy, memory, hunger, inflammation, and mood, to name just a few — and helps keep them in homeostasis or internal balance.
The endocannabinoid system can be activated by common cannabinoids found in the cannabis plant, like THC and CBD, but our body also naturally produces its own cannabinoids (endocannabinoids) — and they also activate the ECS.
Studies show that activation of certain endocannabinoid receptors may worsen cirrhosis, enhancing factors like fibrogenesis, fibrosis, ascites, and steatosis. Activating a different endocannabinoid receptor, however, seems to have the opposite effect, counteracting fibrosis, steatosis, collagen deposition, and inflammation — promoting a healthy liver.
Endocannabinoids have also been shown to impact cirrhosis of the liver. Some can even act against fibrogenesis, improving liver health. So researchers are looking to further explore endocannabinoids as a potential target for the treatment of liver disease.
The benefits of cannabis for liver health
Existing research on the endocannabinoid system shows that activating its receptors via endocannabinoids may have a big impact on the liver — either helping or harming its progress. So how does cannabis, a plant that activates these same receptors, impact the liver?
First of all, it’s important to note that research on medical marijuana and the liver is still in its early stages, and the effects of cannabis on the liver have mostly been studied in populations with liver disease of different kinds — not healthy livers. That said, one small study did look at the influence of chronic cannabis use on liver function in general.
In this study, researchers found no significant differences in liver function for those with higher levels of THC markers in their blood — but they did find slightly better liver function for those with higher THC-OH levels. This research was limited due to a small sample size but suggests that chronic medical marijuana use doesn’t negatively impact liver health for healthy individuals.
Other research looks at cannabis and liver health relative to specific conditions or symptoms. For example, one condition that the effects of cannabis have been investigated is alcoholic liver disease (ALD). ALD is caused by heavy, long term alcohol use, and cannabis just might serve a protective role for this disease.
One very broad study found that those with the highest levels of medical marijuana use had significantly lower levels of ALD at all stages of the disease. These heavy cannabis users saw a 45% reduction in steatosis, or alcoholic fatty liver disease, a 40% reduction in steatohepatitis, or alcoholic hepatitis, a 55% reduction in alcoholic cirrhosis and fibrosis and an impressive 75% reduction in hepatocellular carcinoma, or liver cancer.
Another study, which tied lower levels of ALD to CBD use, seems to suggest that cannabis use (or even just CBD) may actually be protective against the deadly long term effects of alcohol use.
But it’s not just alcohol-induced liver disease that cannabis may help. marijuana may also protect against non-alcoholic fatty liver disease. One study found that cannabis use was tied to lower levels of this condition, in addition to ALD. So medical marijuana may be protective for our livers in general, not just as a protection against drinking.
Cannabis may also play a protective role in other specific conditions.
One study found that cannabis can protect the livers of patients suffering from psychosis — lowering the risk of steatosis.
Animal models also show evidence that cannabis use can improve symptoms of hepatic encephalopathy, likely via the anti-inflammatory properties of cannabis. Unfortunately, there have been no human studies on this condition to confirm the results.
Risk factors for cannabis and the liver
For other liver related conditions, however, cannabis use may have more complicated interactions. Chronic hepatitis C virus, for example, may be worsened by cannabis use. Animal studies show cannabis can actually worsen liver fibrosis and steatosis in hepatitis C. Human studies show that marijuana use can lead to suppression of anti-viral immunity in hepatitis C patients. In addition, studies on hepatitis C patients found that steatosis risk was predicted by daily cannabis smoking.
On the other hand, other studies have reported positive effects for hepatitis C patients using cannabis. One 2018 study found cannabis using hepatitis C patients had lower levels of cirrhosis and lower total health costs than nonusers. Another study found hepatitis C patients who used cannabis were better at adhering to their antiviral treatment and thus had better virologic outcomes. So for patients with this condition, cannabis could be helpful or harmful.
Beyond studies on hepatitis C, other worries for cannabis and the liver come from a study on CBD and mice. In this study, a high dosage of CBD led to fatalities for some of the mice subjects. Researchers noted elevated liver enzymes and increased liver size in the mice who died and concluded they died from liver issues. Other researchers, however, have pointed out some methodological problematic issues in the study.
For one thing, the dose of CBD administered was extremely high — a dose 100 times higher than the maximum recommended dose for Epidiolex, the only FDA approved CBD-based medicine for humans. But more importantly, the CBD was extracted using hexane — a solvent with known neurotoxic properties. It’s unclear whether the hexane was a factor in the mice’s death.
Beyond this, the sample size was only six mice, which is too small to have much statistical significance. Researchers on the study reported that 75% of the mice died — which would mean 4.5 mice died. Since this is an impossibility, we might wonder what other errors were made in this study. More research is needed to confirm or discredit these findings.
Another important area of risk management related to cannabis and the liver is drug interactions. Cannabis can interact with the drug metabolizing enzymes in the liver, which, if taken with certain medications, can cause them to become more or less potent and efficacious. In addition, certain drugs may make cannabis more or less potent.
While there has been little study on these drug interactions, we can deduce from what we know about pharmacology that certain drugs are more likely to have these interactions. For example, fluoxetine, fluvoxamine, fluconazole, clarithromycin, verapamil, itraconazole, voriconazole, and ketoconazole are all more likely to increase the concentration of THC and CBD in the blood by inhibiting its elimination from the body. In the other direction, the drug rifampin has been reported to reduce THC levels in the blood by 20-40% and CBD levels by 50-60%.
In conclusion, cannabis use is growing in popularity, and that should be no surprise considering its wide range of health benefits. Still, while the research is still limited, there are some interesting studies showing both risks and benefits of cannabis use on the liver. For healthy individuals, cannabis should not have a significant impact on liver function — it may even serve a protective role against developing alcoholic liver disease and nonalcoholic fatty liver disease. Still, for those with hepatitis C, or those using certain medications, cannabis use can cause complications.
If you do have a liver condition, it is advisable to work with a cannabinoid specializing physician to ensure you are taking the best steps for your liver health.
Cannabis use shouldn’t cause liver complications and may even potentially play a protective role against developing alcoholic liver disease. Read more
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
- 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:
- 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/Shutterstock.com
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.
- Science & Research
Your trusted source for cannabis information.
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.