Fact check: Is there research behind "cordyceps, reishi and astragalus protect the kidneys and lower creatinine"?
The supplement category most often sold to kidney patients in Asia. We reviewed the Cochrane systematic reviews and Chinese randomised trials: low-quality evidence suggests cordyceps preparations may slightly lower creatinine, but trials were small, short and reported no hard outcomes — and for transplant recipients there are immune-stimulation and drug-interaction concerns.
Check summary
| Item | Detail |
|---|---|
| Claim | "Cordyceps (or reishi, astragalus) protects the kidneys, lowers creatinine and delays dialysis." |
| Verdict | Insufficient evidence. The 2014 Cochrane review found 22 cordyceps trials showing modest improvements in creatinine and proteinuria, rated low-quality evidence (small trials, design flaws, follow-up <1 year, no death/dialysis outcomes). Human kidney studies of reishi and astragalus are even sparser. |
| Evidence level | C (low) |
| Applies to | Almost all participants were CKD stage 3–4 patients in mainland China; no evidence in dialysis; potential harm in transplant (see below) |
| Limits & cautions | Most commercial "cordyceps" is fermented mycelium (Cs-4), not wild fungus; arsenic contamination and variable quality reported; reishi and astragalus are immunomodulators working against anti-rejection drugs. |
| Checked on | 2026-10-13 |
What the evidence says
Cordyceps (Cordyceps sinensis / Ophiocordyceps)
- Cochrane systematic review (Zhang et al., 2014): 22 RCTs, 1,746 CKD patients (mostly China, stages 3–4), cordyceps preparations plus usual care vs usual care. Serum creatinine fell by about 60 µmol/L (≈0.7 mg/dL), 24-h proteinuria decreased, haemoglobin rose slightly — but all trials had high or unclear risk of bias, most follow-up was ≤6 months, and no trial reported death or progression to dialysis. Authors: "low-quality evidence; no reliable recommendation can be made."
- A 2023 updated meta-analysis in a Chinese journal reached similar conclusions: short-term metabolic markers improve, long-term outcomes unknown.
- Mechanistic (animal/cell) studies show anti-inflammatory and anti-fibrotic effects, but animal doses scaled to humans usually far exceed commercial recommendations.
- Safety: adverse events were poorly reported in the review. Wild cordyceps has been found with arsenic above limits (Hong Kong Department of Health, China NMPA sampling); fermented Cs-4 products carry lower arsenic risk but have a different constituent profile.
Reishi (Ganoderma lucidum)
- No randomised trial in CKD patients with kidney function as the primary outcome.
- The 2016 Cochrane review (reishi for cancer) rated evidence insufficient.
- Case reports of hepatotoxicity from reishi powder (Wanmuang et al., 2007) and interactions with anticoagulants.
- For transplant recipients: reishi polysaccharides are studied as "immune enhancers" — exactly the direction anti-rejection drugs suppress; most centres advise avoidance.
Astragalus (Astragalus membranaceus)
- Cochrane 2014 (astragalus for diabetic kidney disease): 25 trials, modest improvements in proteinuria and creatinine, low-quality evidence, mostly short Chinese trials.
- An immunomodulator shown in animals to enhance T-cell function — theoretically unfavourable after transplant.
Why "lower creatinine" is not "kidney protection"
Creatinine is an indirect marker affected by muscle mass, diet and drugs (trimethoprim or cimetidine raise creatinine without changing kidney function). A short-term fall may reflect increased tubular secretion or changed protein intake, not repaired nephrons. The outcomes that matter — long-term eGFR slope, time to dialysis, mortality — have no reliable herbal-trial data.
Practical advice by population
| Population | Advice |
|---|---|
| CKD 3–4 | If you want to try a cordyceps preparation, tell your nephrologist first, choose a licensed product (not loose dried fungus), monitor liver and kidney function, and never reduce proven therapies (SGLT2 inhibitors, ACEi/ARB, finerenone) because of it. |
| Dialysis | No evidence of benefit; high cost; arsenic risk. |
| Transplant | Avoid cordyceps, reishi and astragalus: immune stimulation opposes anti-rejection drugs, and some preparations affect CYP3A4 (see our interactions guide). |
References
- Zhang HW, Lin ZX, Tung YS, et al. Cordyceps sinensis for treating chronic kidney disease. Cochrane Database Syst Rev. 2014;(12):CD008353.
- Zhang HW, Lin ZX, Xu C, et al. Astragalus for treating chronic kidney disease. Cochrane Database Syst Rev. 2014;(10):CD008369.
- Jin X, et al. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev. 2016;(4):CD007731.
- Wanmuang H, et al. Fatal fulminant hepatitis associated with Ganoderma lucidum mushroom powder. J Med Assoc Thai. 2007;90(1):179-181.
- Hong Kong Department of Health, Chinese Medicine Regulatory Office. Public announcements on arsenic in Cordyceps (2016–2019).
- Nowack R. CYP450 enzyme and transporter mediated herb–drug interactions in renal transplant patients. Nephrology (Carlton). 2008;13(4):337-347.
- KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int. 2024;105(4S):S117-S314.
This article compiles publicly available medical information for educational purposes only and is not medical advice. For any health concern, please consult a qualified healthcare professional.
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