Is Activated Charcoal Good for Kidneys?

How Does Activated Charcoal Work?

Activated charcoal (AC) works like a sponge in your stomach and intestines. It grabs onto different chemicals and keeps them from getting into your bloodstream. When you take AC by mouth, it stays the same in your stomach and intestines and doesn't get absorbed.

For people with kidney problems they often eat diets with limited protein to manage symptoms. Through binding with urea and other urine toxins, activated charcoal effectively eliminates them via the feces.

What Are the Risks of Activated Charcoal?

A 2019 study found that around 11% of patients had side effects from the AC, which were primarily digestive disorders, such as constipation and abdominal distention or pain.[1] 4.5% of patients developed abdominal hernias.

Charcoal is also commonly used to remove drugs from the body. It is one of the primary treatments for medication overdose because it will prevent the medication from absorbing into the body. This can be very dangerous for people with kidney disease because it appears to interact with most medications, reducing the effectiveness of those medications.

Is There Research on Activated Charcoal?

Some studies have looked at ways to slow down chronic kidney disease (CKD) by reducing the movement of toxins from the gut into the body. AC has been found in some research to help get rid of waste products like urea and indoxyl sulfate.

In the world’s largest biomedical database - there have been a total of four clinical trials published on AC regarding kidney disease as of 2024:

A 2023 study on those with stage 5 kidney disease on dialysis found that those taking AC had lower urea and phosphorus compared to the placebo group.[2]

A 2019 study on stage 3-4 kidney disease found high blood phosphorus levels occurred in 28% of patients on AC compared to 79% of patients in the placebo group.[3] Around 11% of patients had side effects from the AC, which were primarily digestive disorders, such as constipation and abdominal distention or pain. 4.5% of patients developed abdominal hernias.

A 2009 study on patients with kidney disease found increased clearance of one toxin, indoxyl sulfate, from the body.[4]

A 2006 study on patients with kidney disease found increased clearance of indoxyl sulfate with a compound from AC.[5]

While these studies appear promising, research is still very limited and none of the studies were able to determine outcomes related to the overall benefit to patients. Overall benefit is determined by studying the impact on kidney function and overall survival. While some benefit was found with clearing waste products from the body, none of these studies assessed the overall benefit to longevity and kidney health so it is difficult to determine whether AC could truly help a patient with kidney disease.

Concluding Remarks

Currently there is very limited research to guide the approach with AC and it is very difficult to determine whether AC would help benefit a patient in the end. We do not know whether it is helpful for kidney function or survival of a patient based on available evidence. Furthermore, there are dozens of other therapies that we prioritize at our clinic first that have already demonstrated improvements to longevity and kidney function in research. Some of these alternatives also help to reduce waste products in the body and will not interact with medications like AC does. AC has major interactions with the majority of medications patients with kidney disease are on and should likely be avoided.

Related Topics: Treatments Dialysis Hyperparathyroidism Supplements Bad For Kidney Vitamin B12 Natural Therapies Solitary Kidney

[1] Gao Y, Wang G, Li Y, Lv C, Wang Z. Effects of oral activated charcoal on hyperphosphatemia and vascular calcification in Chinese patients with stage 3-4 chronic kidney disease. J Nephrol. 2019 Apr;32(2):265-272. doi: 10.1007/s40620-018-00571-1. Epub 2018 Dec 26. PMID: 30588573; PMCID: PMC6422957.

[2] Rahman WK, Rabea IS, Meizel MM. Protective effect of activated charcoal against progression of chronic kidney disease: A randomized clinical study. J Med Life. 2023 Sep;16(9):1310-1315. doi: 10.25122/jml-2023-0128. PMID: 38107705; PMCID: PMC10719797.

[3] Gao Y, Wang G, Li Y, Lv C, Wang Z. Effects of oral activated charcoal on hyperphosphatemia and vascular calcification in Chinese patients with stage 3-4 chronic kidney disease. J Nephrol. 2019 Apr;32(2):265-272. doi: 10.1007/s40620-018-00571-1. Epub 2018 Dec 26. PMID: 30588573; PMCID: PMC6422957.

[4] Inaba N, Aoyagi M, Tanase T, Maeda Y, Shiigai T, Tomura S, Kanda E. [Examination of activated charcoal preparations in chronic kidney disease: comparing Kremezin (K) and Merckmezin (M)]. Nihon Jinzo Gakkai Shi. 2009;51(1):51-5. Japanese. PMID: 19238909.

[5] Schulman G. A nexus of progression of chronic kidney disease: charcoal, tryptophan and profibrotic cytokines. Blood Purif. 2006;24(1):143-8. doi: 10.1159/000089451. PMID: 16361855.