Polydatin, also known as piceid, is a natural glycoside form of resveratrol found in plants such as Polygonum cuspidatum (Japanese knotweed). Scientific research over the past decade has explored its potential effects on the kidney system, primarily through preclinical studies. Several animal models have demonstrated that polydatin exerts protective effects against various forms of kidney injury, such as ischemia-reperfusion injury, drug-induced nephrotoxicity (e.g., cisplatin), and diabetic nephropathy. The proposed mechanisms include antioxidant activity, reduction of inflammation, inhibition of apoptosis, and modulation of signaling pathways involved in fibrosis and oxidative stress.

For example, studies in rats have shown that polydatin administration can decrease markers of oxidative stress in renal tissues and reduce histological damage following induced kidney injury. Some cell culture studies suggest that polydatin may inhibit pathways leading to fibrosis, a common outcome of chronic kidney disease. However, despite these promising findings in non-human models, there is a lack of robust clinical trial data in humans. There are no large-scale, peer-reviewed human studies that confirm efficacy or safety for kidney support.

Thus, while there is some scientific rationale and preclinical evidence for the use of polydatin in supporting kidney health, the overall strength of evidence is limited and rated as moderate to low (2/5) due to the absence of clinical validation in humans.