Cannabis, also called weed, is widely used for recreational and medicinal purposes. However, many people wonder whether cannabis is safe for those with liver disease.
Cannabis has exhibited some health benefits and is prescribed medicinally for certain conditions such as epilepsy. But in some other cases, it can do more harm than good.
This article will provide some insight into the available research on cannabis and liver disease and explore whether using it is safe for your liver.
We make it easy for you to participate in a clinical trial for Liver disease, and get access to the latest treatments not yet widely available - and be a part of finding a cure.
The liver has many functions and is one of the most important organs in the human body.
Liver functions include:
Metabolism: Metabolizing medications and compounds from within the body, such as bilirubin
Assisting with immunity
Synthesis of plasma protein such as albumin
Many critical processes can be disrupted when your liver becomes damaged. That's why looking after your liver is essential, especially if you already have liver disease.
Firstly, it's important to know that cannabis contains various compounds. But the primary compounds of interest are the cannabinoids:
Different strains of cannabis will contain different concentrations of THC and CBD. Both compounds have similar effects, but there are some key differences.
For example, THC is a psychoactive substance because it can make you feel high. However, CBD does not have these effects.
Studies have shown that THC and CBD are both metabolized in the liver, and each may have varying effects on it. But other organs, such as the brain, can also interact with these compounds.¹
Metabolism is a scientific word that refers to various chemical reactions inside the body. These reactions typically convert compounds into another form.
The liver is one of the main sites in the body where metabolism occurs. It can perform a range of reactions to synthesize new compounds for the body to utilize. Or it will convert some compounds into a form that makes them easier for the body to excrete.
Since the liver metabolizes THC and CBD, these compounds interact with certain cells in the liver, impacting your liver condition. If you have a liver disease, your liver's metabolism and detoxification processes are not operating at full capacity — hence, it's important to determine whether cannabis is safe for your liver.
It remains unclear whether cannabis has a protective or harmful effect on healthy livers. For example, some studies have suggested that cannabis could protect against fatty liver disease by fighting inflammation.²
However, more research is required to determine the extent of this effect. Studies have not yet reported conclusive findings to indicate the exact cases, frequency of use, and amounts where cannabis could have a positive or a negative effect.
Medical marijuana has shown various therapeutic effects for some health conditions. However,
smoking cannabis may be considered, in certain populations, to cause more harm than good for the liver. For example, in a study of chronic hepatitis C virus (HCV) patients, daily cannabis use was shown to worsen liver fibrosis (scarring). Fibrosis is also a complication that can occur in people with fatty liver disease. Another study has also reported that daily smoking of cannabis was a risk predictor of fatty liver in chronic HCV patients.
On the contrary, some more recent and higher-quality studies have reported a positive influence on HCV outcomes. For example, a 2018 study including 188,333 patient records reported a lower percentage of total health costs and HCV-related liver cirrhosis among cannabis users.
Likewise, a 2019 systemic review and meta-analysis of the available research investigated the impact of cannabis smoking on liver fibrosis in participants with HCV and HIV-HCV co-infection. The study concluded that marijuana was not associated with liver fibrosis in these conditions. Instead, the study noted a reduction in the prevalence of non-alcoholic fatty liver disease (NAFLD) in cannabis users.³
As mentioned previously, studies have been inconclusive on whether cannabis is protective or toxic to the liver. Some studies report that cannabis can make some aspects of liver disease worse (such as fibrosis), while others debunk these findings and even suggest a protective effect of cannabis on the liver due to its anti-inflammatory effects.
Cannabis and cannabinoids such as CBD products have been found to cause an elevation in liver enzymes. They have also shown a low probability of serious liver toxicity with continuous use in high amounts.
Cannabis use was also reported in one study to be associated with a higher rate of ascites (fluid retention in the abdomen) in patients with non-alcoholic fatty liver disease. In this regard, cannabis may be linked to liver disease by potentially accelerating its progression, although more research is required to establish this claim.⁴
You might also wonder if cannabis could be an underlying cause of liver disease.
Many risk factors and causes are linked to liver disease, and these can vary with each type. For example, alcoholic fatty liver disease is caused primarily by alcohol. But other risk factors, such as being obese, can also contribute to its development.
Alternatively, if you have viral hepatitis, this is caused by a viral infection. The primary cause of this liver disease is a virus, which rules out cannabis as a factor.
It's unclear whether cannabis use could be a direct cause of any liver disease — other than the very rare cases reported of hepatotoxicity potentially resulting from the continuous use of high doses of cannabis, more research is required to be sure. It’s recommended to talk to your health professional about cannabis smoking and its impact on your overall health.
As with anything you are unsure about, it's always best to discuss it with your doctor first. For instance, deciding whether it's safe to use cannabis when you have liver disease would be no different from assessing whether it's safe to use a particular medication or supplement. However, it's also good to consider how cannabis interacts with different types of liver disease.
The Canadian Association of Gastroenterology has released a statement regarding the use of cannabis in patients with the following liver disorders:
Cannabis may have a possible protective effect on the liver of patients with alcoholic liver disease. In animal and human studies, cannabinoid use was associated with reduced fatty liver, fibrosis, and carcinoma by lowering inflammation and oxidative stress in ALD patients.
Hepatitis is a condition characterized by inflammation or swelling of the liver. It occurs when liver tissue is infected or injured. As a result, liver function is impaired.
It is inconclusive whether cannabis is protective or harmful in this condition. It has been shown to increase fibrosis in some chronic HCV patients, while it has reduced it in others, especially those co-infected with HIV.
Therefore, try to take caution if you have chronic HCV, as regular cannabis use is not recommended.
Some evidence suggests that cannabis could be a therapeutic agent because it reduces inflammation. Cannabis was also associated with a lower prevalence of NAFLD in two large-scale studies. However, more research studies are needed to confirm these findings before making recommendations on the use of cannabis in this condition.⁵
There is not enough evidence to determine whether people who have undergone a liver transplant should use cannabis. The limited available data on the use of cannabis in this population have found no evidence of negative outcomes. And although it is not absolutely contraindicated for liver transplant recipients to use cannabis, you should consult with your doctor as to whether you can do so, as this should be assessed case by case.
That being said, some medical professionals may warn against using cannabis if you are immunocompromised.
If you have undergone a liver transplant, you will be on medication that suppresses your immune system. The purpose of this medication is to prevent your body from rejecting the donor's liver.
But when your immune system is suppressed, you are more prone to infections. These could be lung infections, and you are even more likely to develop these when smoking cannabis.
In advanced liver disease, there is a greater likelihood that cannabis can interact with liver medications. That's because liver function is impaired, and the liver is not metabolizing cannabis or other compounds like medications as it usually would.
If you are using cannabis, it would be best to disclose this information to your doctor before they prescribe you any medicine. That way, they can avoid potential interactions that may have adverse effects.
Cannabis use can have either a protective or damaging effect on your liver. Studies so far have not been conclusive, with some suggesting positive therapeutic effects of cannabis on the liver, while others reporting some negative effects or worsening of fibrosis in certain conditions.
Overall, the impact of cannabis can vary based on the specific condition the individual has, the amount and frequency of cannabis they smoke, and any other health conditions they may have. If you have any concerns about how cannabis might affect your condition, do not hesitate to mention them to your doctor.
There is limited research on what can be done to protect your liver while smoking cannabis. However, you could consider the implications of smoking cannabis alongside alcohol or while taking certain medications, as combining two or more drugs could negatively impact the liver.
Try to refrain from taking a lot of medications if not necessary, particularly painkillers and cold medications, avoid any street drugs, limit your alcohol consumption, drink plenty of water, and maintain a healthy weight to reduce some of the risk factors associated with developing liver disease.
Physiology, liver (2022)
Cannabis (marijuana) and cannabinoids: What you need to know | NIH: National Center for Complementary and Integrative Health
Physiology, metabolism (2022)
Fatty liver disease | MedlinePlus
Fatty liver disease | MedlinePlus