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What Are CBD Oil Side Effects on Kidneys?

cartoon bottles of cbd

Marijuana (cannabis, pot, weed, ganja, Mary Jane) is the most commonly used recreational drug in the United States. In 2019, some 48 million Americans (approximately 18% of the adult population) reported using it within the past year. Medical cannabis and recreational cannabis are legal in dozens of U.S. states.

Cannabidiol (CBD oil) is often touted as a panacea, a remedy for all manner of diseases. But the use of CBD oil can have unexpected health effects. In this article, we’ll take a look at what the evidence says about the effect of CBD oil on the kidneys in particular.

What is cannabidiol? Is it the same as marijuana?

Cannabidiol (CBD or CBD oil) is an active ingredient in cannabis (marijuana), and it is one among hundreds of ingredients. It is derived from the Cannabis sativa (hemp) plant, the same family as the marijuana cannabis plant. Synthetic cannabinoids (CBD) can also be manufactured in a laboratory. 

The psychoactive ingredient that is primarily responsible for causing the “high” associated with marijuana is THC (tetrahydrocannabinol). CBD contains a lower percentage of THC than marijuana and therefore does not cause a psychoactive effect. But when CBD oil is applied to the skin, inhaled, or eaten, it is believed to have a number of beneficial health effects through its actions on cannabinoid receptors and the endocannabinoid system.

Does CBD oil help kidneys?

CBD is being used for symptom management in a wide variety of health conditions, but there is no solid scientific evidence indicating its safety and efficacy for most conditions. Further research is needed to prove or disprove whether natural and synthetic cannabinoids can improve kidney function or help people with advanced chronic kidney disease.

What are the benefits of CBD oil?

The most robust scientific evidence for the effectiveness of CBD oil is in treating childhood epilepsy syndromes like Lennox-Gastaut syndrome (LGS) and Dravet syndrome. These disorders are often unresponsive to traditional antiseizure medications. The U.S. Food and Drug Administration (FDA) has approved a CBD-containing medication called Epidiolex for the treatment of children with these neurological conditions.

There is also evidence that CBD oil may help with anxiety, insomnia, pain management of chronic neuropathic pain, and reducing cravings in people with addiction to tobacco and some other illegal drugs.

Yet, doctors warn that any health benefits of CBD oil may be offset by the potential harm it can cause. Some of the known adverse effects of CBD include cognitive impairment, respiratory irritation, increased risk of death after a heart attack, orthostatic hypotension (drop in blood pressure with change in position), and cancer (with smoked cannabis). There is also a risk of developing cannabis dependence (addiction).

Drug interactions between CBD and other medications can lead to serious health complications. For example, CBD can increase the level of blood thinners in the body by competing for the same liver enzymes that metabolize (break down) these drugs, thereby increasing the risk of bleeding. 

Is CBD oil hard on the liver or kidneys?

People who take high doses of CBD can develop abnormalities in blood tests that check liver function. Some non-prescription drugs, such as acetaminophen (Tylenol), have a similar effect. You should tell your doctor if you are using CBD regularly, for example, to treat chronic pain. Your doctor may adjust the dose of a prescription medication or warn you about using CBD oil with certain over-the-counter medications. 

In terms of the effect of CBD oil on the kidneys, the jury’s still out. There is some evidence that CBD oil may be harmful to the kidneys, but there is also evidence that it might help renal function. The majority of CBD and THC is excreted through the feces, and therefore a CBD dose adjustment is usually not required in people with chronic kidney disease. However, scientists and doctors are unsure exactly how CBD affects the kidneys, so caution is advised in people with kidney diseases. 

Does CBD oil hurt your kidneys?

Let’s take a more detailed look at what the research shows about CBD oil's side effects on kidneys, specifically in patients with chronic kidney disease, end-stage renal disease, diabetic nephropathy, kidney stones, or other kidney health issues.

A 2018 study found that cannabis users with impaired kidney function have a faster decline in kidney function compared to non-cannabis-users. However, since the study participants consumed both THC and CBD products, it was unclear which of these products caused the decline in kidney function. 

On the positive side…

A 2009 study in the Journal of Pharmacology and Experimental Therapeutics showed that CBD could help to reduce oxidative stress, inflammation, and nephrotoxicity (kidney damage from toxins or drugs).

A 2015 study showed that endocannabinoid system receptors (CB1 and CB2 receptors) are present in the central nervous system and in the kidneys, where they regulate blood flow and reduce inflammation, oxidative stress, and renal fibrosis (scarring).

A 2017 study showed that cannabinoids could potentially have a beneficial effect on the kidneys in healthy people. However, the effects of CBD are not well known in people with chronic kidney disease, severe renal impairment, acute kidney injury, polycystic kidney disease, or other kidney diseases.

A 2020 review found no evidence that CBD oil can affect kidney function adversely in people with normal renal function. However, some CBD products may contain toxic contaminants like solvents, pesticides, and heavy metals, which can be harmful to the kidneys. 

So, it remains unclear whether CBD’s effects on kidneys are good or bad. For now, we can only say that the preliminary research is neither positive nor negative, and the evidence remains inconclusive. 

Wrapping Up

We don’t know enough about how CBD oil affects the kidneys. We know even less about the appropriate dosage for the medicinal effects of CBD, especially in people with acute kidney injury, chronic kidney disease, kidney failure, or kidney transplantation. Expert guidance on how to dose and administer medical marijuana safely and effectively is not available. 

In contrast, prescription medications used to treat kidney diseases are studied extensively for safety and efficacy. They are prescribed to treat specific symptoms, rather than a broad range of potential benefits typically assigned to CBD. 

It is also unclear whether any potential beneficial effects of CBD oil on the kidneys outweigh the possible harmful effects. 

Last but not least, CBD oil is marketed and sold as a supplement and is not regulated by the FDA. Therefore, it’s difficult to be sure that cannabidiol extracts sold online actually contain the ingredients listed on the label.

Given the lack of strong scientific evidence either way, it is vital that you consult your healthcare provider before taking CBD oil, especially if you have kidney disease. When using CBD oil for treating symptoms, start at a low dose and go slow, increasing the dose every few days to ensure no complications. 


  1. https://www.cdc.gov/marijuana/data-statistics.htm#
  2. https://www.health.harvard.edu/blog/cannabidiol-cbd-what-we-know-and-what-we-dont-2018082414476
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6388458/
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  7. https://www.asn-online.org/education/kidneyweek/2018/program-abstract.aspx?controlId=3017229
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