Wormwood and kidney health is an unusual corner of this plant’s literature, because it contains something most wormwood claims do not: an actual human trial, published in a serious nephrology journal, with a striking result. It also contains a published report of kidney harm.
Both are small enough that neither settles anything, and reading them together is more informative than reading either alone. Nothing here is medical advice, and wormwood has not been approved by the FDA to diagnose, treat, cure, or prevent IgA nephropathy or any other kidney condition. Kidney disease requires a nephrologist.
Key Takeaways
- A 2010 pilot trial in the American Journal of Kidney Diseases gave 10 patients with biopsy-proven IgA nephropathy 1.8 g/day of a thujone-free wormwood preparation for six months [1].
- Urine protein-creatinine ratio fell from 2,340 to 315 mg/g, and the reduction held through a further six months off the supplement [1].
- The trial was uncontrolled. There was no placebo group, and every patient stayed on dual renin-angiotensin system blockade throughout [1].
- Estimated GFR and creatinine clearance were unchanged across the whole study period [1], so this was a proteinuria result, not a kidney-function result.
- The rationale was TNF-alpha reduction, a cytokine implicated in the pathophysiology of IgA nephropathy [1].
- On the other side, a 2024 case report describes acute kidney injury with interstitial nephritis in a 17-year-old after chronic intake of a three-plant mixture containing wormwood [2].
- The trial preparation was thujone-free. An ordinary wormwood supplement is not, which means the trial does not describe what is on most shelves.
What IgA Nephropathy Is, and Why Proteinuria Is the Target
IgA nephropathy is the most common primary glomerular disease worldwide. Immunoglobulin A deposits in the glomeruli, the kidney’s filtering units, and the resulting inflammation damages the filter. Protein that should stay in the blood leaks into the urine.
Proteinuria is not just a marker of that damage; it is a driver of further damage and the strongest predictor of progression to kidney failure. Reducing it is the central goal of treatment, which is why blockade of the renin-angiotensin system is standard care.
That standard-of-care detail is what makes the trial design so consequential. Everyone in the study was already on the treatment known to reduce proteinuria, and stayed on it. Any additional change has to be interpreted against that background.
The Trial, in Its Own Terms
Ten patients were enrolled, all with biopsy-proven IgA nephropathy, normal kidney function, and a history of at least three months of proteinuria between 500 and 3,500 mg per day despite ongoing dual renin-angiotensin system blockade. In other words, these were people whose proteinuria had not responded adequately to the best available treatment [1].
They received 1.8 grams per day of a thujone-free wormwood preparation for six months, without stopping their existing medication. Urine protein-creatinine ratio and blood pressure were assessed monthly, and follow-up continued for a further six months after the supplement was withdrawn [1].
Urine protein-creatinine ratio fell from 2,340 plus or minus 530 mg/g at baseline to 315 plus or minus 200 mg/g at the end of supplementation, a highly significant change, and remained stable through the supplement-free follow-up. Mean arterial blood pressure showed a moderate but significant decrease. Estimated glomerular filtration rate and endogenous creatinine clearance were unchanged throughout [1].
Taken at face value that is a large effect in a population defined by not responding to treatment, and the persistence after withdrawal is unusual enough to be interesting.
The Four Reasons to Hold That Result Loosely
The authors published this as a pilot uncontrolled trial, and the phrase is doing real work. Four limitations follow directly from the design.
No control group. Ten patients all received the supplement and all were compared only to their own baseline. IgA nephropathy proteinuria varies substantially over time on its own. Without a parallel group, spontaneous fluctuation and the intervention are indistinguishable.
Concurrent treatment continued. Everyone remained on dual renin-angiotensin system blockade for the entire study [1]. Any lag or cumulative effect from that ongoing therapy sits inside the observed change.
Ten patients. At that size a small number of individual responses drives the group mean, and the confidence around any estimate is wide.
Kidney function did not move. eGFR and creatinine clearance were unchanged [1]. Reduced proteinuria is a meaningful surrogate, but this trial did not demonstrate preserved kidney function, and it was not long enough to.
The right reading is that this is a hypothesis-generating result that justified a proper randomized controlled trial. That trial does not appear to have been run in the fifteen years since.
The Detail That Breaks the Transfer to Supplements
One specification in the methods matters more than anything else on this page for a reader deciding what to buy.
The preparation used was thujone-free [1].
Thujone is the monoterpene ketone that defines wormwood’s safety profile, modulating GABA type A receptors and producing dose-dependent seizures in animals above threshold concentrations [3]. It is also, for most consumers, the compound a wormwood product is implicitly sold on, and the reason wormwood is used in short courses rather than continuously.
A thujone-free preparation at 1.8 grams per day for six months is therefore a different substance and a different exposure than a standard wormwood extract. Taking an ordinary wormwood supplement for six months to chase this result would mean six months of thujone exposure the trial participants did not have, in pursuit of an effect the trial cannot attribute to any single compound.
Anyone reasoning from this study to a purchase needs to check that the product matches the preparation tested, which our guide to reading wormwood labels and our article on third-party testing both cover. In practice, thujone-free wormwood is a specific and uncommon product category.
The Evidence Pointing the Other Way
A 2024 report in Case Reports in Nephrology describes a 17-year-old patient with severe acute renal failure, together with oesophagitis, erosive gastritis, and an inflammatory anaemia, with no obvious cause identified on investigation [2].
Once other explanations were excluded, the syndrome was attributed to chronic intake of a mixture of three medicinal plants: Artemisia absinthium, Marrubium vulgare, and Centaurium erythraea. Renal biopsy showed interstitial nephritis without antibody deposits, and the authors reported it as the first documented case of acute kidney injury linked to these three plants [2].
The obvious limitation is that three plants were taken together and none can be individually implicated. Wormwood may have had nothing to do with it.
The reason it belongs beside the trial is symmetry of evidence quality. Both are small, neither can establish causation, and they point in opposite directions on the same organ. Anyone citing the proteinuria result as a reason to take wormwood for kidney health is applying a standard of evidence that would equally require them to take the interstitial nephritis report seriously as a reason not to. The case reports are covered in more detail in our article on published wormwood poisoning cases.
The consistent conclusion from both papers is the same one the case-report authors reached: these preparations are widely assumed to be safe on the basis of weak evidence, and that assumption has not been tested.
A Note on the Evidence
The kidney evidence for wormwood consists of one uncontrolled 10-patient pilot trial with no control group and one case report of harm. Neither design can establish cause and effect, and they point in opposite directions.
Frequently Asked Questions
What did the IgA nephropathy trial find?
Urine protein-creatinine ratio fell from 2,340 to 315 mg/g over six months of supplementation and stayed down through a further six months without the supplement [1]. That is a large change, in 10 patients, with no control group.
Why does the lack of a control group matter so much?
IgA nephropathy fluctuates on its own, and all 10 patients stayed on renin-angiotensin system blockade throughout. Without a comparison group there is no way to separate the supplement from the ongoing treatment or from natural variation [1].
What kind of wormwood was used in the trial?
A thujone-free preparation at 1.8 grams per day [1]. That is an important detail: thujone-free is not what a standard wormwood supplement is, so the trial does not transfer to an ordinary product.
Has wormwood been linked to kidney damage?
One 2024 case report describes a 17-year-old with severe acute renal failure and biopsy-confirmed interstitial nephritis after chronic intake of a mixture containing wormwood and two other plants [2]. Three plants together means none can be individually blamed.
Should someone with kidney disease take wormwood?
That decision belongs with a nephrologist. Reduced kidney function changes how substances are cleared, the trial evidence is one uncontrolled pilot, and there is a published report of renal harm on the other side.
Why was wormwood tested for this at all?
The rationale was TNF-alpha. That cytokine is implicated in the disease process of IgA nephropathy, and earlier laboratory and clinical observations suggested wormwood could lower TNF-alpha levels [1].
References
- Krebs S et al. Wormwood (Artemisia absinthium) for poorly responsive early-stage IgA nephropathy: a pilot uncontrolled trial. American Journal of Kidney Diseases (2010). PMID 20843592
- Selles A et al. Acute Kidney Injury Following the Ingestion of a Medicinal Plants Mixture: A Case Report. Case Reports in Nephrology (2024). PMID 39735399
- Lachenmeier DW. Wormwood (Artemisia absinthium L.), a curious plant with both neurotoxic and neuroprotective properties? Journal of Ethnopharmacology (2010). PMID 20542104
These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease. Content is for informational purposes only and is not medical advice; consult a qualified healthcare provider before starting any supplement. As an Amazon Associate we earn from qualifying purchases.
