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Draft: not yet reviewed by a clinician

Use this page to prepare questions for your care team. It does not replace their advice. Your own targets and doses come from your nephrologist, diabetes team and renal dietitian.

Supplements and herbal products

No doses on this page

This handbook never gives insulin or medicine doses and never tells you to change one. Your prescriber sets every dose and every change, and writes down when to pause a medicine and when to restart it. A low blood glucose is always treated straight away: see Treating a low and Get help now.

In short

No supplement without your nephrologist's OK, and kidney-specific ("renal") vitamins only if your team prescribes them. "Natural" does not mean safe. Some herbs damage the kidneys. Others build up when the kidneys cannot clear them, interact with your medicines, or hide potassium or phosphorus (NKF; AKF; NKF). KDIGO asks care teams to review and limit over-the-counter and herbal products for everyone with kidney disease (KDIGO 2024, practice point 4.1.3).

Why supplements are riskier with kidney disease

  • The kidneys clear them. Some herbal products leave the body through the kidneys, so with kidney disease they can build up to toxic levels (NKF).
  • Some harm the kidneys directly. Aristolochic acid, found in some traditional Chinese herbal remedies, causes serious kidney damage (KDIGO 2024, chapter 4).
  • They are not checked like medicines. Rules on what is in a supplement, and how pure it is, vary widely from country to country (KDIGO 2024, chapter 4). The label may not tell you everything.
  • They interact with your medicines. They can make a medicine weaker or too strong (NKF). For example, St John's wort lowers tacrolimus levels and raises the risk of rejection of a transplant (Prograf label).

Herbs and products to avoid

NKF lists these as especially risky in kidney disease (NKF):

  • alfalfa, aloe vera (taken by mouth), aristolochia, arnica, astragalus, bearberry (uva ursi), cat's claw, chaparral, comfrey, creatine, goldenrod, horsetail, java tea leaf, licorice root, nettle, Oregon grape root, parsley root, pennyroyal, rue, St John's wort and yohimbe.

The American Kidney Fund adds barberry, celery (Apium graveolens) supplements and huperzine (AKF).

Star fruit (carambola) is on KDIGO's list of products reported to harm the kidneys. Avoid it as a fruit, a juice or a supplement (KDIGO 2024, Figure 45; Food lists).

Hidden potassium, phosphorus and magnesium

Some products carry minerals that build up when your kidneys cannot clear them:

Product What it can hide Source
Labels that say "electrolyte support" or "high in minerals" potassium NKF
"Green" and "superfood" powders potassium and phosphorus NKF
Seaweed and algae products (kelp, dulse, spirulina, chlorella) and seed-based products phosphorus; kelp and dulse also potassium NKF
Noni, dandelion, turmeric and coconut-water products potassium NKF
Everyday vitamin and mineral pills bought off the shelf phosphorus and potassium NKF
Protein powders and shakes check the label for phosphate additives Label reading

Check labels for magnesium too: it builds up to dangerous levels when the kidneys fail (StatPearls; Medicines to avoid). Ask your team before using any of these products.

Read the ingredient list as well as the numbers. Any ingredient with "phos" in the name is a phosphate additive (Phosphate additives).

"Kidney cleanse" and "detox" products

There is no supplement that cleans or repairs the kidneys. Some "cleanse" products contain herbs from the lists above. KDIGO's list of remedies reported to harm the kidneys includes a "colon, kidney, liver, spleen purifier" that contained aloe vera, cascara sagrada, chaparral and bearberry (KDIGO 2024, Figure 45). Skip them.

Creatine and vitamin C

  • Creatine (a body-building supplement) has been linked with kidney inflammation (KDIGO 2024, chapter 4). It also raises your blood creatinine, which makes your eGFR look worse than it is (KDIGO 2024, Table 8; eGFR and creatinine).
  • Vitamin C in large amounts can leave oxalate crystals in the kidneys (KDIGO 2024, chapter 4). High-dose vitamin C can also make FreeStyle Libre sensors read falsely high (Abbott), which could hide a low.

If you have a transplant

  • Avoid St John's wort: it has many interactions and lowers tacrolimus levels, which raises the risk of rejection (NKF; Prograf label).
  • Avoid grapefruit and grapefruit juice with tacrolimus. The FDA says Seville oranges, pomelos and tangelos may act the same way (Prograf label; FDA).
  • Check every supplement, tea and herbal remedy with your transplant pharmacist first (After a transplant).

What to do

  • Before you start any supplement, vitamin, herbal tea or powder, ask your kidney team.
  • Bring every bottle and packet to your next visit, including teas and powders. NIDDK advises bringing your list or your bottles to every visit (NIDDK).
  • Add supplements to your medicine list, with the brand name.
  • Use one pharmacy, so it can check for interactions (NIDDK).
  • If your team prescribes a vitamin, ask for the exact product, because ordinary vitamin and mineral pills can carry minerals you need to limit (NKF).
  • Ask before stopping anything your team prescribed.

Examples

  • A "hydration" powder. Lee adds an electrolyte powder to his water bottle after the gym. The label lists potassium. He stops buying it and asks his dietitian about a kidney-friendly way to rehydrate.
  • A gift from a friend. Nina is given a "kidney detox tea" with uva ursi and parsley root. Both are on the lists above. She does not drink it and shows the box to her team.
  • Creatine and a worse eGFR. Omar's eGFR drops from 52 to 44 after he starts creatine for the gym. He tells his team. They ask him to stop the creatine and recheck in a few weeks, possibly with a cystatin C test (eGFR and creatinine).

Ask your care team

  1. Is there any supplement or vitamin I should take? Which product exactly?
  2. Is my protein or electrolyte powder safe for me?
  3. I take an herbal product. Can you check it against my medicines and my kidneys?
  4. I have a transplant. Which teas and remedies are off limits?
  5. Can I take vitamin C or vitamin D, and how much?

Get help now if…

  • After a new supplement: muscle weakness, a slow or irregular heartbeat, or much less urine: call your team today, or call 911 (or your local emergency number) if you faint, feel very weak or your heartbeat is very slow or irregular. These can be signs of high potassium or kidney injury (MedlinePlus). See Get help now.

Sources

Not yet reviewed by a clinician. Facts and sources last checked 2026-10-06.