Does Cannabis Affect Your Kidney Health?

A 2017 study published in the American Journal of Physiology: Renal Physiology notes human use of cannabis and cannabis products for medicinal purposes has been documented since 4000 B.C. in ancient Asia. However, the Marijuana Tax Act kicked off almost a century of federal marijuana prohibition in the U.S. starting in 1937, which continued with the war on drugs throughout the 1980s. In the 1970s, the federal government placed cannabis in the most restricted category of drugs, labeling it a Schedule I illegal substance. 

The DEA defines this drug category as having no medical use and a high potential for abuse. Fortunately, clinical research around cannabis and its effects on organs, including the kidneys, has significantly advanced since the 1930s. The former study seeks to answer the question, "Does cannabis affect your kidney health?" And, if cannabis does affect kidney function, how much cannabis is safe to use?

As cannabis use grows in popularity along with spreading state decriminalization and potential federal legalization, health-conscious consumers may worry about the risks and benefits associated with cannabis consumption.

But there's good news for cannabis consumers. A substantial 2017 study published in The American Journal of Medicine found no correlation between cannabis consumption and kidney function, at least in moderation for healthy adults. A robust 2020 review in Current Opinion in Nephrology and Hypertension further supported this conclusion. And at least one other study suggests cannabis may offer a safer solution for kidneys than traditional analgesics or opioids for long-term pain management, according to Science Daily.

In the 2017 study, 13,995 adults aged 18-59 participated in the National Health and Nutrition Examination Survey from 2007 to 2014. Of the study participants, 6,483 self-reported never using marijuana, 5,499 had used cannabis in the past, and 2,013 were actively consuming cannabis during the study. Researchers evaluated serum creatinine concentration and estimated glomerular filtration rate (eGFR) to assess the likelihood of participants having stage 2 or later chronic kidney disease. In conclusion, researchers found no significant correlation between current or past cannabis use and kidney function.

The 2020 review, which was prepared by Dr. Joshua L. Rein, a nephrologist at Mount Sinai, evaluated 156 independent clinical studies and determined cannabis does not affect kidney function in healthy individuals. The study concluded that cannabis might effectively relieve symptoms of advanced chronic kidney disease (CKD) and end-stage renal disease and may reduce opioid use in patients who use cannabis.

The first 2017 study mentioned in this article looked at the effects cannabis has on the kidneys. Kidneys contain CB1 and CB2 receptors. Cannabis activates these receptors within the endocannabinoid (EC) system, leading researchers to speculate using cannabis agonists to modulate CB receptors may protect against renal injury and offer effective therapies for patients with existing renal injury and disease.

This study concluded that cannabis use may benefit kidney health under certain circumstances and recommends more research be conducted into the role of cannabis in kidney health. But that recommendation will be met with difficulty as long as researchers must contend with federal prohibition. 

A 2022 study in the European Journal of Pain calls cannabis research "the Bermuda triangle of low-quality studies." Continuing federal prohibition of cannabis has blocked widespread, cohesive medical studies into the plant's physiological effects. 

What data researchers have been able to gather is often incomplete or inaccurate, according to a comprehensive 2017 review conducted by the National Academies of Sciences, Engineering, and Medicine. The review revealed stubborn regulatory and supply barriers that impede research on cannabis and cannabinoids, along with funding limitations due to marijuana criminalization.

Still, current studies like the ones mentioned here seem to support the conclusion that cannabis does not affect kidney health and could even offer beneficial treatment for symptoms of kidney injury and disease.