Your kidneys already detox your blood. Around 180 liters of it pass through their filters every day. There is no tea, cleanse, or herb that makes them do it better, and some of the products sold for that purpose have put people on dialysis.
I am not against supplements. I am against the ones that hurt kidneys, and against spending money on ones that do nothing. Here is how to tell the difference.
Can you flush your kidneys with water?
Not in the way the phrase suggests. Drinking more water makes more urine, but it does not clean the kidneys or improve how well they filter. For most healthy adults, drinking to thirst, with pale yellow urine, is enough.
There are two groups who benefit from deliberately drinking more:
- People who form kidney stones. The goal is about two and a half liters of urine a day, which dilutes the minerals that form stones.
- People who get frequent urinary tract infections. Extra water reduced repeat infections in a 2018 trial.
For people with chronic kidney disease, a large trial that coached patients to drink more water did not slow kidney decline. And drinking far more than you need can drive sodium dangerously low. People with heart failure or advanced kidney disease often need to limit fluid, not increase it.
Herbal supplements and kidney health
Most herbs sold for kidney health have little or no evidence behind them. A few carry real risk.
| Product | The concern |
|---|---|
| Aristolochia (birthwort, some traditional Chinese herbal mixes) | Causes severe, permanent kidney scarring and urinary tract cancer. Banned in many countries but still turns up in imported products |
| High-dose vitamin C (1,000 mg or more daily) | Turns into oxalate, raising kidney stone risk, especially in men |
| Turmeric and curcumin supplements | High in oxalate. A concern for stone formers at supplement doses, not cooking amounts |
| Licorice root | Raises blood pressure and lowers potassium |
| Noni juice, some green and herbal drinks | High in potassium, risky with kidney disease |
| Star fruit | Contains a toxin that failing kidneys cannot clear. Can cause confusion and seizures in kidney disease |
| St. John's wort | Lowers levels of transplant anti-rejection drugs |
| "Detox" and "cleanse" kits with laxatives or diuretics | Can cause dehydration and acute kidney injury |
| Bodybuilding and weight-loss supplements | Sometimes contaminated with hidden drugs or steroids |
What about the popular "kidney" herbs?
Dandelion root acts as a mild diuretic and contains potassium. Not dangerous for most healthy people, not helpful either, and not a good idea with kidney disease or on potassium-raising medications.
Chanca piedra is marketed as a "stone breaker." The human evidence is very limited, and it is not a substitute for finding out why your stones form.
Cranberry may modestly help prevent repeat urinary infections in some women. It does not treat kidney disease and can interact with warfarin. Concentrated cranberry pills are high in oxalate.
Apple cider vinegar, lemon water, and alkaline water do not shrink cysts, dissolve most stones, or improve kidney function. Lemon water does add a little citrate, which can help some stone formers, but prescription potassium citrate is far more reliable.
Why supplements are a bigger risk with kidney disease
Kidneys clear many supplements and their contaminants. When kidney function is reduced, those substances build up. Many products also carry potassium or phosphorus that a healthy kidney would handle easily and a damaged one cannot.
Supplements are not tested by the FDA for safety or purity before they are sold. What is on the label is not always what is in the bottle.
What actually protects your kidneys
The things that work are less exciting than a cleanse:
- Keep blood pressure and blood sugar at goal
- Avoid regular NSAIDs such as ibuprofen and naproxen
- Do not smoke
- Take kidney-protective medications as prescribed, if you have kidney disease
- Get your eGFR and urine albumin checked once a year if you have diabetes or high blood pressure
Bring your bottles
Before you start anything new, and at every kidney visit, bring every supplement you take, in its original container. We look up the ingredients, check for interactions with your medications, and tell you plainly which ones to keep and which to stop. Our kidney health and wellness page and our post on coffee and your kidneys cover more everyday questions.
Signs a supplement may be hurting your kidneys
Call your doctor and stop the product if, after starting something new, you notice:
- new swelling in your feet, ankles, or around your eyes
- foamy urine, or much more or much less urine than usual
- blood pressure readings that suddenly run higher
- muscle weakness, cramps, or palpitations
- a creatinine on your labs that rose after you started it
Most supplement-related kidney injury improves when the product is stopped early. Bring the bottle with you.
Getting care in Houston
Remix Medical is a physician-owned practice with nephrology offices in Montrose near the Texas Medical Center, East Houston, Katy, and Groesbeck, plus video visits anywhere in Texas. A supplement review is part of every new kidney visit. Most plans are accepted, including Medicare, Medicare Advantage, and Texas Medicaid. Book an appointment and bring your supplement bottles.