Supplements for Kidney Health: What to Avoid and What's Safe
With kidney disease, potassium, magnesium, phosphorus and many herbs can be dangerous. See which supplements need a doctor's OK and how to protect your kidneys.
By the editorial team · Updated Oct 14, 2026 · 2 sources cited
When it comes to supplements for kidney health, avoiding harm matters more than adding pills. With kidney disease, potassium, magnesium, phosphorus, high-dose vitamin C and many herbal products can build up or damage the kidneys. Vitamin D and iron are often needed but should be prescribed and monitored. No supplement has been shown to restore kidney function.
Evidence-ranked options
| Supplement | Evidence | Typical dose | Notes |
|---|---|---|---|
| Vitamin D (as prescribed) | B | Prescribed form and dose | Kidneys activate vitamin D; doctors often prescribe special forms. |
| Iron (if anemic, as prescribed) | B | As prescribed | Anemia is common in chronic kidney disease. |
| Potassium, magnesium supplements | D | Avoid unless prescribed | Can build up to dangerous levels. |
| 'Kidney cleanse' herbs | D | Avoid | No evidence; some herbs are toxic to kidneys. |
A: strong · B: moderate · C: limited or mixed · D: good evidence of no benefit. See the evidence database.
Protect your kidneys
- Keep blood pressure and blood sugar in target
- Avoid regular high-dose NSAID painkillers unless advised
- Stay hydrated, don't smoke
- Get kidney tests if you have diabetes, high blood pressure or a family history
Bring every supplement to your appointments. Check combinations in our safety database.
Frequently asked questions
Can supplements improve kidney function?
No supplement has been shown to improve kidney function. Controlling blood pressure and blood sugar protects the kidneys.
Is creatine bad for kidneys?
In healthy people it hasn't shown harm, but it raises creatinine on blood tests. People with kidney disease should avoid it unless their doctor agrees.
Sources
Educational content, not medical advice. Read our medical disclaimer.