Dietary supplements are widely used to support energy, immunity, overall wellness, and more. While many are safe when used appropriately, some can affect kidney function, especially if taken in large amounts or if you have a preexisting kidney condition.
Your kidneys help filter waste and keep nutrients in balance. Because supplements can be more concentrated than food, certain ones may put extra pressure on this system. Whether a supplement is helpful or not for the kidneys depends on what you take, how much, and your individual health status.
Can you take supplements if you have kidney disease?
Yes. Some supplements may still be useful if you have kidney disease. However, it’s important to be thoughtful about which ones you use.
When kidney function changes, your body may process vitamins and minerals differently. This means that some nutrients can build up in the body, while others may be harder to maintain at healthy levels or interfere with your condition if taken without guidance.
In some cases, supplements may even be recommended to support your health, especially if your diet is limited, your appetite is low, or treatments like dialysis are affecting nutrient levels. Some commonly considered supplements for kidney disease include:
- Vitamin D for bone health
- Iron for anemia
- B vitamins for energy and red blood cell production
- Omega-3 fatty acids for heart health
Each of these serves a specific purpose and is not to be taken at random. Whether you need them is usually determined through your lab results, diet, and stage of kidney disease.
What supplements are harmful to the kidneys?
Some supplements, even vitamins, can be harmful for the kidneys, especially when taken in high doses, for long periods, or without proper medical guidance. For people with kidney disease or those at risk, understanding which supplements to approach with caution is especially important.
Germanium
This trace element has been linked to kidney damage when taken in very large amounts over a long period of time. In reported poisoning cases, excessive intake led to the formation of germanium dioxide deposits in the kidneys, causing significant damage. While lower doses are sometimes marketed for health benefits, long-term use without supervision isn’t recommended.
Creatine monohydrate
Often used for muscle performance and recovery, creatine is generally safe in standard doses for healthy people. Higher doses don’t add benefits and may increase the kidneys’ workload. If you have kidney concerns, it’s best to check with a healthcare professional prior to introducing creatine to your supplement routine.
Chromium picolinate
Chromium helps with blood sugar metabolism, but high-dose supplementation has been linked in some reports to kidney problems. It may also interfere with medications such as insulin, corticosteroids, and nonsteroidal anti-inflammatory drugs (NSAIDs). Because the positive effects of chromium are not well-established, the risks may outweigh the benefits for some people.
Potassium supplements
Potassium is essential for nerve and muscle function, but too much can become dangerous. Healthy kidneys regulate potassium levels effectively. However, impaired kidneys may struggle to remove excess potassium. This can lead to hyperkalemia, a condition where potassium levels get too high, affecting heart rhythm and potentially becoming life-threatening. Common sources like potassium supplements and salt substitutes should be used carefully.
Phosphorus supplements
Phosphorus supports bone health, but too much can build up when the kidneys aren’t filtering efficiently. This can weaken bones and cause calcium deposits in blood vessels and organs, which increases the risk of a cardiovascular event.
Herbal supplements
Herbal products are often assumed to be safe because they’re “natural,” but they can still pose significant risks. Many are not strictly regulated, meaning contamination with heavy metals or undeclared ingredients is possible. What specific herbs are bad for the kidneys? Some containing aristolochic acid, such as birthwort and wild ginger, may be directly toxic to the kidneys.
The following, though not an exhaustive list, may also affect how well the kidneys work:
- Astragalus
- Barberry
- Cat’s claw
- Goldenrod
- Horsetail
- Java tea leaf
- Licorice root
- Nettle, stinging nettle
- Oregon grape root
- Parsley root
- Uva ursi
Vitamin C (in high doses)
Is vitamin C bad for your kidneys? In normal amounts, no. But high-dose supplements (around 1,000 mg or more daily) may increase the risk of kidney stones in some people. A 2022 study found that men taking high-dose vitamin C supplements had about double the risk of developing kidney stones, likely due to increased oxalate in the urine.
Magnesium
Magnesium supports many body functions, but excessive intake, especially from supplements, can be harmful. High doses can cause diarrhea, nausea, and, in severe cases, magnesium toxicity. This can lead to low blood pressure, irregular heartbeat, and even cardiac arrest. The risk is much higher in people with reduced kidney function, whose bodies cannot efficiently remove excess magnesium.
Do you need supplements?
Not always. Many people can meet their nutrient needs through a balanced diet that includes a variety of whole foods. In fact, nutrients from food are often easier for the body to absorb and use than nutrients from supplement sources.
That being said, supplements can be helpful in certain situations — such as when you have a diagnosed deficiency, a restricted diet, or specific health needs related to kidney disease. Blood tests, the presence of certain symptoms, and guidance from your healthcare team can help determine if you truly need them.
Instead of thinking of supplements as a routine habit, it can help to view them as targeted support when needed.
Support your health with the right guidance from Health Loft
As you’ve seen, some supplements may affect health in a negative manner, especially when used without proper guidance. If you’re wondering which supplements are bad for your kidneys, this may be best answered by a thorough lab assessment conducted by a qualified healthcare professional.
It’s also helpful to keep in mind that supplements are just one part of the picture. Everyday food choices play a central role in supporting kidney health and overall well-being, and a balanced, thoughtful eating pattern can often reduce the need for unnecessary supplementation.
At Health Loft, our registered dietitians specializing in kidney health can review what you’re taking, flag anything that may not be necessary, and guide you toward dietary choices that fit your lifestyle, symptoms, and health aspirations.
We can also work with you and your care team to build a personalized plan that ensures you get exactly what you need — nutritionally and in other aspects of recovery and symptom management.
Let a Health Loft dietitian help you to move forward with increased confidence in what nourishes your body. Connect with our team today.
This article was reviewed by Haleigh Mann, MS, RDN, LDN. It is intended for informational purposes only and does not replace personalized nutritional advice.
