Mulberry leaves, fruit, and bark show consistent kidney-protective effects across dozens of laboratory and animal studies, particularly in models of diabetes-related kidney damage, high uric acid, and drug-induced kidney injury. The catch is that virtually all of this evidence comes from rodents and cell cultures, not human clinical trials. No one has yet run a large, controlled study in people to confirm that eating mulberry fruit or drinking mulberry leaf tea reliably improves kidney function. What exists is a surprisingly deep body of preclinical research pointing in a favorable direction, with a few important safety caveats that deserve attention.
Diabetic Kidney Damage Is Where the Evidence Runs Deepest
The largest cluster of mulberry-kidney research focuses on diabetic nephropathy, the progressive kidney deterioration that affects a significant share of people with diabetes. In diabetic rats, mulberry leaf tea reduced blood glucose, improved insulin sensitivity, and lessened markers of chronic kidney damage. The researchers attributed these effects to compounds abundant in mulberry leaves, including a sugar-metabolism inhibitor called 1-deoxynojirimycin (1-DNJ), along with flavonoids, polyphenols, and polysaccharides.1Journal of Functional Foods. Mulberry leaf tea alleviates diabetic nephropathy by inhibiting PKC signaling and modulating intestinal flora A separate study using black mulberry fruit extract in diabetic rats found improvements in markers of oxidative damage and reduced scarring of the kidney’s filtering units.2Oxford Academic. Black mulberry fruit extract alleviates streptozotocin-induced diabetic nephropathy in rats: targeting TNF-α inflammatory pathway
Alkaloids extracted from mulberry twigs (sold in China as an approved diabetes drug called SZ-A) also reduced blood glucose, 24-hour urinary protein excretion, and the albumin-to-creatinine ratio in diabetic animals, all indicators of improving kidney function.3PubMed. Morus alba L. (Sangzhi) alkaloids alleviate diabetic nephropathy by suppressing endoplasmic reticulum stress and modulating AMPK-associated phosphatidylethanolamine content Meanwhile, a study using mulberry leaf extract in diabetic mice showed reduced glomerular damage and less tubule fibrosis compared to untreated diabetic controls, though the reduction in urinary albumin did not reach statistical significance at all doses tested.4Phytomedicine Plus. Protective effects of Morus alba Linn leaf extract on streptozotocin-induced diabetic nephropathy in mice model
A systematic review and meta-analysis pooling preclinical studies on mulberry leaf polysaccharides found that treated animals had significantly lower serum creatinine, blood urea nitrogen, 24-hour urinary protein, and urinary microalbumin compared to controls. The analysis also tied these polysaccharides to delayed kidney fibrosis, reduced inflammatory activity, and regulation of insulin-related pathways.5PubMed Central. Preclinical Evidence of Mulberry Leaf Polysaccharides on Diabetic Kidney Disease: a Systematic Review and Meta-Analysis That meta-analysis is probably the strongest piece of evidence in the entire mulberry-kidney literature, because it synthesizes multiple animal studies rather than relying on any single experiment. But “strongest preclinical evidence” is still not human evidence.
Uric Acid, Gout, and Kidney Strain
High uric acid puts stress on the kidneys and, over time, can contribute to kidney disease and gout. Several mulberry studies have zeroed in on this problem. Mulberry fruit extract suppressed xanthine oxidase, the enzyme primarily responsible for producing uric acid, while also adjusting the expression of urate transport proteins in the kidney to help flush uric acid out more efficiently.6PubMed. Mulberry (Fructus mori) extract alleviates hyperuricemia by regulating urate transporters and modulating the gut microbiota Mulberry leaf extract likewise inhibited xanthine oxidase and reduced hepatic uric acid production while downregulating a kidney transporter that normally reabsorbs uric acid back into the blood.7Food Science and Human Wellness. Integrative study of the anti-hyperuricemic mechanism of mulberry leaf extract: network pharmacology and animal model validation
The compound mulberroside A, found naturally in mulberry branches, reduced serum uric acid in hyperuricemic mice, increased uric acid excretion in urine, and improved markers of kidney function including creatinine clearance. It did this by turning down transporters that pull uric acid back into the body and turning up transporters that push it out.8PubMed. Mulberroside a possesses potent uricosuric and nephroprotective effects in hyperuricemic mice A broader extract from mulberry twigs produced a similar pattern: lower serum urate, higher urinary urate excretion, lower blood urea nitrogen and creatinine, and improved kidney function overall in hyperuricemic mice.9Journal of Ethnopharmacology. Uricosuric and nephroprotective properties of Ramulus Mori ethanol extract in hyperuricemic mice
This dual action, reducing production of uric acid and increasing its excretion, is the same two-pronged strategy that prescription drugs for gout use. That mulberry compounds hit both prongs in animal models is one of the more compelling findings in the literature. Whether the effect is strong enough to matter clinically in a person drinking mulberry tea or eating mulberry fruit is an open question.
Protection Against Drug-Induced and Acute Kidney Injury
Some of the most practically interesting mulberry research involves cisplatin, a widely used chemotherapy drug notorious for damaging kidneys. Bioactive compounds isolated from mulberry fruit protected kidney cells against cisplatin-induced damage in laboratory cultures by reducing the activity of stress-signaling and cell-death pathways.10PubMed Central. Beneficial Effects of Bioactive Compounds in Mulberry Fruits against Cisplatin-Induced Nephrotoxicity In a whole-animal study, the flavonoid-rich fraction of mulberry leaf extract significantly reduced the spikes in blood urea nitrogen and creatinine that cisplatin typically causes and prevented structural damage to the kidney tissue, though a crude hydroalcoholic extract was not effective, suggesting that the protective compounds need to be concentrated or isolated.11PubMed Central. Protective effects of the Morus alba L. leaf extracts on cisplatin-induced nephrotoxicity in rat
Beyond chemotherapy, a 2025 study examined mulberrin, a flavonoid from mulberry, in a model of ischemia-reperfusion injury, the kind of acute damage kidneys suffer when blood supply is temporarily cut off (during surgery or a blood pressure crash, for example). Mulberrin improved kidney function, reduced cell death, and restored markers of cellular energy production. The mechanism involved activating a protein called Sirt3 that controls the cell’s antioxidant defenses; when the researchers silenced Sirt3, mulberrin’s protective effect disappeared.12PubMed Central. Mulberrin Alleviates Renal Ischemia–Reperfusion by Inhibiting Ferroptosis and Oxidative Stress Through Sirt3 Activation This is the kind of clean mechanistic work that builds a plausible case for how mulberry compounds act, even though it remains far from a clinical application.
Kidney Scarring and Fibrosis
Regardless of what initially harms the kidneys, chronic damage tends to end the same way: fibrosis, where scar tissue replaces functional kidney tissue. Several mulberry studies have targeted this process directly. Chlorogenic acid-rich mulberry leaf extract significantly reduced collagen deposition in a rat model of kidney obstruction, cutting the fibrotic area roughly in half compared to untreated animals. Expression of key fibrosis drivers like TGF-β1 also dropped sharply.13PubMed. Chlorogenic acid-rich Morus alba leaf alleviated renal fibrosis through the regulation of transforming growth factor-beta 1 (TGF-β1) and fibroblast growth factor-2 (FGF-2), and extracellular matrix deposition
Mulberry leaf bioactives modulated a receptor called PPARγ in diabetic rat kidneys, which in turn influenced inflammatory markers tied to nephropathy progression.14PubMed. Morus alba Leaf Bioactives Modulate Peroxisome Proliferator Activated Receptor γ in the Kidney of Diabetic Rat and Impart Beneficial Effect A study combining different mulberry leaf active components found that specific ratios of mulberry flavonoids and alkaloids relieved metabolic disorders and kidney damage in diabetic rats through the same TGF-β/Smads fibrosis pathway, suggesting that the combination worked as well as isolated components.15PubMed. Combination of mulberry leaf active components possessed synergetic effect on SD rats with diabetic nephropathy by mediating metabolism, Wnt/β-catenin and TGF-β/Smads signaling pathway A separate formulation using mulberry root bark combined with a traditional Chinese herbal blend, delivered as nanoparticles, also reduced the fibrotic area in rat kidneys by dampening TGF-β1 expression.16Nanoscience and Nanotechnology Letters. Efficacy of Cortex Mori–Liuwei Dihuang Nanoparticle Pills on Renal Interstitial Fibrosis via TGF-β/Smad Signaling
The consistency here is striking. Study after study in different labs, using different parts of the mulberry plant, finds reduced expression of TGF-β and related signaling molecules in the kidney. That pathway is central to kidney scarring in humans too, which is one reason researchers keep investigating mulberry as a candidate renoprotective agent. But consistency in rodent results does not always predict human outcomes, and many promising natural compounds have fizzled in clinical trials.
Kidney Stones and a Dose-Dependent Surprise
One study on black mulberry (Morus nigra) extract and kidney stone formation produced a result that anyone interested in mulberry for kidney health should know about. At lower concentrations, the extract reduced formation of calcium oxalate crystals (the most common type of kidney stone component) in both their monohydrate and dihydrate forms. It also showed a diuretic effect, which would generally be favorable for stone prevention. But at the highest concentration tested, crystal formation actually increased significantly.17PubMed. Dose-Dependent Dual Effect of Morus nigra L. Extract on Urinary Parameters of Hypertensive Rats
This dose-dependent reversal matters. It suggests that moderate mulberry consumption could help prevent stones, but concentrated supplements or extracts taken in large amounts might backfire. The study was conducted in hypertensive rats, so the exact doses that trigger the switch in humans are unknown. Still, it is a useful caution against the more-is-better mindset that often surrounds natural remedies.
Which Part of the Mulberry Plant Matters
One complication for anyone trying to translate this research into practical decisions is that different studies use different parts of the plant. Mulberry leaves are the most studied for kidney benefits, particularly in the context of diabetes and uric acid. Mulberry fruit (both white and black species) has been tested for cisplatin protection and anti-stone effects. Mulberry twig bark and root bark appear in uric acid and fibrosis studies. The bioactive compounds overlap but are not identical across plant parts. Leaves are rich in flavonoids, 1-DNJ, chlorogenic acid, and polysaccharides. Fruit contains anthocyanins and cyanidin glycosides. Twigs and root bark contain stilbenes like mulberroside A and oxyresveratrol.
Mulberry leaf tea is by far the most accessible form for everyday consumption, and it happens to be the form with the broadest evidence base for kidney-related effects. Mulberry fruit is widely eaten fresh, dried, or as juice. Concentrated extracts and supplements vary enormously in composition and dose, and the kidney stone finding above is a reminder that concentration matters.
A Real Drug Interaction to Take Seriously
If you take cyclosporine, a common immunosuppressant used after organ transplants and for autoimmune conditions, mulberry may be a genuine problem. A study in rats found that a single dose of mulberry reduced the blood levels of cyclosporine by more than half, and repeated dosing still cut levels substantially. The mechanism involved mulberry boosting the activity of enzymes and transport proteins that break down or pump out cyclosporine before it can work.18Journal of Agricultural and Food Chemistry. Potential Risk of Mulberry-Drug Interaction: Modulation on P-Glycoprotein and Cytochrome P450 3A Cyclosporine has a narrow therapeutic window, meaning even modest changes in blood levels can lead to organ rejection (if too low) or toxicity (if too high). The same enzyme pathways mulberry affects, P-glycoprotein and CYP3A, are involved in processing many other drugs as well. If you are on medications metabolized by these pathways, mentioning mulberry consumption to your prescriber is worth the conversation.
Contamination Risks You Would Not Expect
Mulberry trees are remarkably good at absorbing heavy metals from soil and air, which is sometimes a virtue (they are used for environmental remediation) and sometimes a hazard for anyone eating the fruit or leaves. A study of mulberry trees grown in an urban setting in Iran found that the fruit was contaminated with aluminum, nickel, arsenic, cadmium, and lead at levels well above international safety limits, with aluminum and cadmium running three to six times over permissible levels and lead about four times over.19Archives of Hygiene Sciences. Potential Health Risk of Heavy Metals Accumulation in Cultivated Mulberry in Urban Landscapes of Arak, Iran: A Case Study Cadmium and lead are especially harmful to the kidneys over time. A separate study near chromite mining areas in Pakistan similarly found elevated heavy metal concentrations in local food crops including white mulberry.20PubMed. Health risk assessment from contaminated foodstuffs: a field study in chromite mining-affected areas northern Pakistan
The irony is real: a plant whose compounds protect kidneys in controlled experiments could contribute to kidney damage if grown in contaminated soil near roads, factories, or mines. This does not apply to all mulberry products, but it does mean that sourcing matters. Mulberry from agricultural regions with clean soil and water is a different proposition from fruit picked off a tree beside a busy highway.
What Would It Take to Move from Animal Studies to Real Recommendations
The gap between where mulberry-kidney research stands and what it would need to support dietary recommendations is wide. The animal work is broad, mechanistically coherent, and largely consistent across labs and mulberry species. That is more than many herbal remedies can claim. But the history of translational medicine is littered with compounds that looked great in rodents and did nothing, or worse, in people. Antioxidants are a classic example: spectacular in cell and animal models, disappointing in most large human trials.
What the field needs are dose-finding studies in people (to determine how much mulberry consumption actually changes relevant biomarkers like serum creatinine, uric acid, or urinary albumin), followed by randomized controlled trials of reasonable duration. Some early-stage clinical work on mulberry and blood sugar already exists in the diabetes space, but kidney-specific endpoints have not been the primary focus. Until that work is done, the honest assessment is that mulberry is a promising but unproven candidate for kidney health, and eating mulberry or drinking mulberry leaf tea is unlikely to cause harm for most people at normal dietary amounts. It just cannot yet be recommended as a treatment or prevention strategy for any specific kidney condition.
Mulberry Leaf Tea in Traditional Medicine Systems
Mulberry leaf has been used in traditional Chinese, Korean, and Japanese medicine for centuries, primarily for blood sugar regulation but also for what classical texts describe as “nourishing the liver and kidneys.” In traditional Chinese medicine, different parts of the mulberry tree are considered distinct medicinal substances: the leaf (Sang Ye), the twig (Sang Zhi), the fruit (Sang Shen), and the root bark (Sang Bai Pi) each have their own classical indications. The root bark, in particular, has been traditionally used for its diuretic properties. While traditional use is not evidence of efficacy in a modern biomedical sense, it is worth noting that the traditional indications overlap with exactly the areas where preclinical research is now finding activity. That overlap is not coincidental; it is part of the reason mulberry attracted so much research attention in the first place, particularly in East Asian research institutions where traditional pharmacopeias serve as a starting point for drug discovery.