How does CBD affect the liver?

What effects does CBD have on the liver? Can it be harmful? How can we make sure our liver is healthy? Today on the Cannactiva blog we answer these and other questions with Dr Masha Burelo, a researcher who reviews the scientific studies on the effects of CBD on the liver.

In short: at low doses, CBD is considered safe for the liver in healthy people. The risk appears when it is used at very high doses – more than 1,000 mg a day – or combined with certain medications.

What effects does CBD have on the liver?

CBD or cannabidiol is a non-psychoactive compound extracted from cannabis that has gained great popularity in recent years for its benefits, which include its properties for pain, anxiety and improving sleep.

Naturally, as its popularity has grown, questions have arisen about its safety, specifically about its effects on the liver.

In general, current studies show that CBD is safe at low doses, with adverse effects that are rare and mild, such as reduced appetite or drowsiness.

The greatest risk to the liver appears when CBD is used at high doses or combined with certain medications. According to the studies, high doses start at 1,000 mg of CBD a day (the equivalent of two 10 ml bottles of 5% CBD oil) or more than 20 mg of CBD per kg a day (for example, 800 mg a day for a person weighing 40 kg).

Note: This is an informational article and is not intended to prevent, diagnose or treat any disease. Its content may complement, but should never replace, any diagnosis or treatment of any disease or symptom. Cannactiva products are not medicines and are intended for external use. Bear in mind that new scientific evidence may emerge. For all these reasons, consult your doctor before using CBD.

How does the liver metabolise CBD?

The liver processes CBD through the cytochrome P450 (CYP450) enzymes, the same system that breaks down most medications. That is why, when CBD is taken alongside other drugs, the two can compete for these enzymes, which alters their levels in the blood. This mechanism explains both the possible interactions and why high doses put more strain on the liver. You can see how long it stays active in how long CBD lasts in the body and check the details of combinations in CBD interactions with medications.

Effects of CBD on the liver

The impact of cannabidiol on liver health has been the subject of numerous scientific studies and research.

The liver is a vital organ: it regulates the chemical levels in the blood, metabolises many substances (including CBD), detoxifies harmful compounds, filters blood from the digestive tract and synthesises important proteins for blood clotting. It is precisely because of this last function that caution is advised when combining CBD with anticoagulants such as Sintrom.

Some studies suggest that CBD may offer protective effects in certain liver injuries, reducing inflammation and oxidative stress. However, at high doses it has been associated with an increase in liver enzymes, an indicator of inflammation or damage in the liver.

Most of the risks associated with CBD occur at very high doses or when used together with certain medications. This is especially relevant in countries where oral CBD use is permitted, as it tends to be used without medical guidance and at very high doses.

In preclinical studies (in animals or isolated cells, not in humans), CBD has shown potential hepatoprotective effects against various liver injuries, including the reduction of inflammation and oxidative stress and an improvement in metabolic dysregulation in liver diseases.

Some studies suggest that CBD may help improve the health of a liver damaged by alcohol consumption and the associated inflammation. If you want to learn more, see the post on mixing CBD with alcohol (1).

Other research indicates that the hepatic endocannabinoid system could have therapeutic potential for chronic liver diseases such as hepatitis C, although these benefits are not yet fully validated and more research is needed.

On the other hand, the use of CBD at high doses has been linked to an increase in liver enzymes in the blood, which are released in greater amounts when liver cells are in an inflammatory process. In some cases, people who receive high daily doses may develop abnormalities in these enzymes consistent with liver toxicity.

Can CBD damage the liver?

At normal doses and in healthy people, the risk of liver damage from using CBD is low, provided there are no contraindications.

However, CBD at high doses can indeed damage the liver, especially when combined with certain medications. High doses start at 1,000 mg (1 gram) of CBD a day – the equivalent of half a 10 ml bottle of 20% CBD oil – or more than 20 mg per kg a day. A scientific review suggests that the risk at low doses is low, though not negligible.

For all these reasons, it is important to consult a doctor before using CBD, especially if you are taking other medications. More information: optimal CBD dose.

High doses of CBD and their effects on the liver: scientific studies

A systematic review and meta-analysis found a significant association between the use of high doses of cannabidiol and elevated liver enzymes, as well as with drug-induced liver injury (DILI). Specifically, high doses of CBD (1,000 mg/day or more, or 20 mg/kg/day or more) and the concurrent use of antiepileptics were risk factors.

No serious cases of liver injury were reported, and no cases were observed in adults using doses below 300 mg of CBD a day (4).

Another study used a “quantitative systems toxicology” approach to understand how CBD might cause liver toxicity, especially at high doses. It concluded that combining CBD with valproate (VPA), a medication for seizures, produced the same liver enzyme alterations as taking CBD alone in high daily amounts (3). This is why special caution is advised with high doses.

Can CBD at normal doses damage the liver?

A study focused on long-term CBD consumption and its impact on liver function in healthy adults found no significant association between the cannabidiol dose and the liver test values.

Moreover, most of the elevations observed were mild and were probably related to the conditions or medications for which people were taking CBD, rather than to the cannabidiol itself (5). More information: CBD interactions with medications.

How can I tell if CBD is damaging my liver?

The first thing is to use CBD appropriately and on the advice of a professional. There is no way to tell at home whether your liver is damaged: some liver conditions cause no obvious symptoms and are difficult to detect.

Even so, it is advisable to see a doctor if these warning signs appear:

• Yellowing of the skin or eyes (jaundice)
• Pain or discomfort in the upper right part of the abdomen
• Intense or persistent fatigue
• Nausea or vomiting
• Elevated liver enzymes (ALT/AST) in a blood test

If you still have doubts about your liver health, ask your doctor for a blood test to measure liver enzymes and other parameters which, together with professional assessment, will tell you whether your liver is healthy.

Conclusion

In summary, the impact of CBD on the liver is complex and highlights the need for further research in this area. While some studies indicate that CBD may have hepatoprotective effects, others suggest that high doses could be associated with liver alterations.

With the current data, the safest approach is to use low doses of CBD and, above all, to consult a doctor before including it in a therapeutic regimen. If you want to learn about the other adverse effects, see the post on CBD side effects and long-term toxicity.

Note: This is an informational article and is not intended to prevent, diagnose or treat any disease. Its content may complement, but should never replace, any diagnosis or treatment of any disease or symptom. Cannactiva products are not medicines and are intended for external use. Bear in mind that new scientific evidence may emerge. For all these reasons, consult your doctor before using CBD.