What Supplements Help Kidneys and Liver Function?

A handful of supplements have genuine evidence behind them for supporting liver and kidney health, but the list is shorter than the supplement industry would have you believe. Most of the research points to compounds that work as antioxidants, helping these organs manage the oxidative stress they face from filtering toxins and metabolic waste. Here’s what the evidence actually shows, what’s overhyped, and what can cause harm.

Milk Thistle for Liver Protection

Milk thistle extract, known as silymarin, is the most studied liver supplement on the market. A systematic review of clinical trials found that about 66% of studies reported reduced liver enzyme levels in people taking silymarin, while roughly 21% showed no significant change. In some of the strongest results, patients saw ALT and AST reductions (two key markers of liver cell damage) between 60% and 89%. These improvements appeared most consistently in people with fatty liver disease, drug-induced liver injury, or metabolic conditions like type 2 diabetes.

Silymarin works through two main pathways. It boosts your body’s production of glutathione and glutathione peroxidase, which are your cells’ primary internal antioxidants. It also helps stabilize liver cell membranes, slowing the uptake of toxins into liver tissue. Typical study doses ranged from 280 to 420 mg daily, split across two or three doses.

The picture isn’t universally positive, though. In a large, double-blind trial of patients with chronic hepatitis C who hadn’t responded to previous treatment, neither 420 mg nor 700 mg of silymarin three times daily made a meaningful difference in liver enzymes over 24 weeks. Silymarin appears most useful for metabolic and toxin-related liver stress rather than chronic viral infections.

Curcumin Benefits Both Organs

Curcumin, the active compound in turmeric, is one of the few supplements with evidence for both liver and kidney protection. In the liver, curcumin activates protective pathways that raise glutathione levels and prevent the activation of stellate cells, which are the cells responsible for scar tissue formation in liver fibrosis. In the kidneys, it suppresses a signaling cascade involved in scarring and protects the cells lining your kidney tubules from transforming into scar-producing tissue.

The catch with curcumin is absorption. On its own, your body eliminates most of it before it reaches your bloodstream. Formulations that include piperine (from black pepper) or use specialized delivery systems dramatically increase how much your body can actually use. If you’re considering curcumin, the formulation matters more than the dose printed on the label.

NAC and Glutathione Support

N-acetylcysteine is the supplement form of an amino acid your body uses to produce glutathione. Hospitals have used it for decades as the standard treatment for acetaminophen overdose because it directly replenishes the glutathione that your liver burns through when detoxifying the drug. In a clinical study of patients with non-alcoholic fatty liver disease, oral NAC at 600 mg twice daily improved liver function markers. For general liver support, NAC’s value comes from giving your body the raw material to maintain its own antioxidant defenses.

Astragalus for Kidney Function

Astragalus root, widely used in traditional Chinese medicine, has some of the more interesting clinical data for kidney support. In a study of 37 patients with mild to moderate chronic kidney disease, kidney filtration rate improved from an average of 66 to 70 ml/min after taking astragalus-containing preparations. That’s a modest but statistically significant gain, especially considering that kidney function in CKD typically declines over time rather than improving. The study was small and used a self-controlled design (comparing patients to their own prior results), so it’s promising but not definitive.

Alpha Lipoic Acid and Kidney Protection

Alpha lipoic acid has shown protective effects against diabetic kidney damage in animal studies. In diabetic rats, supplementation prevented the rise of creatinine, blood urea nitrogen, and urine albumin-to-creatinine ratio, all markers of kidney deterioration. It also reduced inflammatory markers and increased glutathione content in kidney tissue. The protective effects appeared to work through multiple channels: reducing blood sugar, calming inflammation, preventing scarring, and blocking cell death in kidney tissue. Human trials are still limited, but the animal data is consistent enough that alpha lipoic acid is frequently studied alongside conventional diabetes treatments.

B Vitamins for Kidney Disease

If you have chronic kidney disease, B vitamins deserve specific attention. Vitamins B9 (folic acid) and B12 help your body make red blood cells and can help manage the anemia that commonly accompanies CKD. The other B vitamins, including B1, B2, B3, B5, B6, and B7, support energy production and nerve health. The National Kidney Foundation notes that specialized B-vitamin formulations exist specifically for people with CKD, available by prescription under names like Nephrocaps and Nephro-Vite.

There’s an important caution here. Your kidneys normally clear excess water-soluble vitamins, including B vitamins and vitamin C. When kidney function is reduced, these can build up and cause problems. Fat-soluble vitamins A, E, and K are even more concerning because your body stores them rather than excreting them. Most people with CKD get enough of these through food alone, and supplementing can lead to toxic accumulation. A standard multivitamin is not necessarily safe if your kidneys aren’t filtering normally.

What Didn’t Hold Up

Two popular supplements fell short of their reputation in clinical testing. Omega-3 fatty acids are often recommended for kidney health, but a meta-analysis examining their effect on proteinuria (excess protein in urine, a key marker of kidney damage) found no statistically significant benefit. The overall effect was essentially zero under both statistical models used, and results varied wildly between individual studies.

SAMe (S-adenosylmethionine) is marketed heavily for liver support. Animal studies looked promising, showing it could prevent alcohol-related liver damage in baboons and micropigs. But in a 24-week randomized, placebo-controlled trial of 37 patients with alcoholic liver disease, SAMe at 1.2 grams daily was no more effective than placebo. Both groups saw improvements in liver enzymes, but that turned out to be driven by abstinence from alcohol rather than the supplement itself. Liver tissue biopsies confirmed no difference in inflammation, fat buildup, or scarring between the SAMe and placebo groups.

Supplements That Can Damage These Organs

Some herbal supplements marketed as “natural” remedies are genuinely toxic to the liver, kidneys, or both. Aristolochic acid, found in certain traditional weight-loss formulas, causes progressive and irreversible kidney scarring. This was first documented in Belgium in 1993 when patients taking herbal weight-loss preparations developed kidney fibrosis. The problem arose partly because one plant was accidentally substituted for another, a risk that persists with loosely regulated herbal products.