{"url":"https://whatshealthyandwhy.com/rehmannia/kidney-adrenal-and-blood-sugar","path":"/rehmannia/kidney-adrenal-and-blood-sugar","alternates":{"json":"https://whatshealthyandwhy.com/api/articles/rehmannia/kidney-adrenal-and-blood-sugar.json","markdown":"https://whatshealthyandwhy.com/rehmannia/kidney-adrenal-and-blood-sugar.md"},"topic":{"slug":"rehmannia","name":"Rehmannia","url":"https://whatshealthyandwhy.com/rehmannia"},"slug":"kidney-adrenal-and-blood-sugar","order":1,"title":"Kidney Support, Blood Sugar, and Adrenal Health","question":"Does Rehmannia help kidney function, blood sugar and adrenal health?","answer":"Rehmannia may reduce urine protein loss in kidney disease when added to standard treatment; blood sugar and adrenal benefits rest mainly on animal studies.","description":"How Rehmannia glutinosa (Di Huang) supports kidney function, regulates blood sugar, modulates inflammation, and helps the adrenal-pituitary axis — with evidence from clinical trials, randomized studies, and mechanistic research","confidence":2,"confidenceNote":"Kidney: one 8-week trial (479 people) on top of irbesartan; skin: one 22-person trial; blood sugar and adrenal claims rest on animal data.","evidenceSummary":{"rctCount":2,"observationalCount":0,"metaAnalysisCount":0,"totalParticipants":"~500","replicated":false,"newestStudyYear":2024},"category":{"categoryTitle":"What's Good For You","categorySlug":"good-for-you","subcategoryName":"Herbs & Spices","subcategorySlug":"herbs","url":"https://whatshealthyandwhy.com/explore/good-for-you/herbs"},"actions":["With kidney disease, ask your nephrologist first; the trial added 400 mg a day of acteosides to irbesartan for 8 weeks [2].","Standardized extracts typically run 500–1,500 mg a day; high doses, especially raw preparations, can cause loose stools."],"cautions":["Use caution in pregnancy and if you take diabetes medicines, since Rehmannia may lower blood sugar further.","Blood sugar and adrenal effects are not proven in people, so do not swap it for prescribed diabetes or steroid treatment.","The kidney result is from 8 weeks of combination therapy; long-term outcomes such as dialysis were not tracked [2]."],"simpleText":"Rehmannia (Rehmannia glutinosa, known in traditional Chinese medicine as Di Huang) is one of the most widely used herbs in the Chinese pharmacopeia, prized for over two thousand years as a kidney and adrenal tonic. Modern pharmacology has identified over 70 active compounds in its root — including iridoid glycosides, polysaccharides, and catalpol — that explain its broad effects on blood sugar regulation, kidney function, and inflammatory signaling. [1] A randomized controlled trial in nearly 500 patients with chronic kidney disease found that Rehmannia acteosides added to standard treatment reduced urinary protein loss significantly more than standard treatment alone. [2] In metabolic research, its polysaccharides lowered blood glucose, total cholesterol, and pro-inflammatory cytokines in diabetic animal models, suggesting potential utility in metabolic syndrome. [3] It remains one of the few traditional herbs where both classical uses and emerging clinical data point in the same direction.","mediumText":"How Rehmannia Works\n\nRehmannia root contains a diverse phytochemical profile, with three main compound classes driving most of its documented health effects: iridoid glycosides (primarily catalpol and acteoside/verbascoside), Rehmannia polysaccharides (RGP), and a range of amino acids and oligosaccharides. Dried and processed (steamed) root — called Shu Di Huang — differs chemically from fresh root (Sheng Di Huang) and is used for different indications in traditional medicine, though both have overlapping benefits.\n\nKidney and Renal Protection\n\nThe best-documented clinical benefit of Rehmannia is its support for kidney function. Its acteosides (phenylpropanoid glycosides) have been shown in clinical trials to reduce proteinuria — protein leaking into urine is an early marker of kidney damage and a predictor of disease progression.\n\nIn the 2014 randomized controlled trial [2], 479 patients with primary chronic glomerulonephritis were divided between standard irbesartan treatment and irbesartan plus Rehmannia glutinosa acteosides (400 mg/day). After 8 weeks:\n- The Rehmannia group reduced 24-hour urinary protein by 36.4% from baseline\n- The irbesartan-only group reduced it by 28.0% (p = 0.028)\n- Glomerular filtration rate, blood pressure, and safety markers were comparable between groups\n\nThe proposed mechanisms include reduction of oxidative stress in renal tubular cells, inhibition of pro-fibrotic signaling (TGF-β1), and anti-inflammatory actions that protect the glomerular filtration barrier. [1] Animal models of 5/6 nephrectomy (surgically induced kidney failure) have shown that Rehmannia extracts slow progressive renal failure, in part by reducing fibrosis and inflammatory infiltration.\n\nBlood Sugar and Metabolic Effects\n\nRehmannia polysaccharides are the primary active compounds for metabolic support. In animal research, oral administration of purified RGP to streptozotocin-induced diabetic mice [3] produced:\n- Significantly reduced fasting blood glucose\n- Lower total cholesterol and triglycerides\n- Increased insulin levels, suggesting preserved or improved pancreatic beta-cell function\n- Reduced vascular inflammation markers (TNF-α, IL-6) in aortic tissue\n- Decreased malondialdehyde (a marker of oxidative stress) and increased antioxidant enzyme activity\n\nThe polysaccharides appear to work through multiple pathways: improving insulin sensitivity at the cellular level, protecting pancreatic beta cells from oxidative damage, and reducing the chronic low-grade inflammation that drives insulin resistance and vascular disease.\n\nA review of Korean clinical and experimental publications [4] confirmed this metabolic activity across multiple study designs, with consistent findings on blood glucose reduction and antioxidant effects across both in vitro and clinical data points.\n\nAdrenal and HPA Axis Support\n\nRehmannia has a traditional reputation as an adrenal tonic — specifically for supporting the body under conditions of prolonged stress or glucocorticoid exposure. The pharmacological basis for this is the ability of Rehmannia constituents to modulate the hypothalamic-pituitary-adrenal (HPA) axis.\n\nAnimal research has shown that Rehmannia antagonizes the suppressive effects of chronic glucocorticoid administration on HPA function — essentially helping the axis recover from cortisol-induced feedback suppression. This is clinically relevant for people tapering off steroid medications, where HPA recovery is often slow. The active compounds appear to stimulate adrenocortical activity and restore normal cortisol pulsatility after suppression. [1]\n\nRehmannia is also classified in TCM as a \"Yin tonic\" — used specifically for conditions characterized by excessive heat, dryness, night sweats, and low back weakness, which map loosely onto adrenal depletion states in functional medicine frameworks.\n\nAnti-inflammatory and Antioxidant Actions\n\nCatalpol, one of the primary iridoid glycosides in Rehmannia, has broad anti-inflammatory effects: it inhibits NF-κB signaling, reduces production of TNF-α and IL-1β, and scavenges reactive oxygen species. These effects are evident across the kidney, nervous system, and vascular tissue. [1]\n\nThe Korean review [4] summarized findings from 30 publications covering antioxidant effects, blood glucose reduction, and cardiovascular protective effects, concluding that Rehmanniae Radix is effective for various inflammatory and metabolic conditions.\n\nSkin and Anti-aging Effects\n\nA 2024 double-blind, randomized, placebo-controlled trial [5] in women aged 18–35 with moderate-to-severe acne found that oral supplementation with Rehmannia glutinosa leaf extract (100 mg/day) for 56 days:\n- Reduced acne severity scores by 21.7% vs 14.2% in the placebo group\n- Improved skin hydration and quality-of-life measures\n- Produced benefits visible as early as 28 days\n\nThis adds a skin health dimension to Rehmannia's profile — the anti-inflammatory and antioxidant properties of its leaf compounds appear to have systemic effects on skin inflammatory conditions, not just the traditional root-based indications.\n\nForms and Dosage\n\nRehmannia is available in several forms with different indications:\n\n- Fresh or dried root (Sheng Di Huang): cooling, anti-inflammatory, used for acute heat conditions — 9–30 g/day in decoctions (traditional TCM dosing)\n- Prepared/steamed root (Shu Di Huang): nourishing and warming, used as a long-term tonic for kidney and blood deficiency — 9–30 g/day in formulas\n- Standardized extracts: typically 500–1,500 mg/day of dried extract equivalent; acteoside content varies\n- Polysaccharide extracts: most research uses doses equivalent to 300–600 mg of purified polysaccharide\n\nRehmannia is commonly used in traditional Chinese medicine as part of compound formulas — the classic \"Six Flavor Rehmannia\" formula (Liu Wei Di Huang Wan) contains Rehmannia as the chief herb alongside five others addressing kidney and liver Yin deficiency.\n\nIt is generally well tolerated at therapeutic doses. Some people experience loose stools or digestive discomfort at high doses, particularly with the raw preparation. Caution applies in pregnancy and in people taking hypoglycemic medications, given its blood sugar-lowering activity.\n\nSee our Astragalus page for a complementary TCM tonic with strong evidence for immune function and kidney protection. See our Adaptogen overview for broader context on HPA axis support herbs.","deepText":"Evidence Review\n\nZhang, Li & Jia 2008 — Comprehensive Pharmacological Review\n\nThis landmark review in the Journal of Ethnopharmacology [1] remains the most cited English-language synthesis of Rehmannia's chemistry and pharmacology. The authors analyzed more than 70 identified compounds and mapped their biological activities across organ systems.\n\nKey pharmacological actions documented:\n\nBlood system: Rehmannia polysaccharides promote hematopoiesis — the production of blood cells — and protect bone marrow from suppression. This is consistent with its traditional use for blood deficiency syndromes.\n\nImmune system: Both stimulatory and modulatory effects were documented, including activation of macrophages, enhancement of T-cell and NK-cell activity, and anti-inflammatory cytokine modulation. The net effect is immunomodulatory rather than simply immunostimulatory.\n\nEndocrine system: Catalpol and other constituents influence insulin secretion, adrenocortical function, and thyroid hormone metabolism. The review confirmed HPA axis modulation, specifically antagonism of glucocorticoid-induced suppression.\n\nCardiovascular system: Cardioprotective effects include hypotensive activity (reduction of blood pressure), reduced lipid peroxidation, and protection against atherosclerosis in animal models.\n\nNervous system: Catalpol has neuroprotective properties — in models of neurodegeneration, it reduced neuronal death and preserved acetylcholine neurotransmitter levels, suggesting potential relevance in cognitive aging.\n\nThe authors noted that despite the breadth of preclinical evidence, rigorous large-scale clinical trials were limited at the time of publication, and called for more work to establish dose-response relationships and pharmacokinetic profiles in humans.\n\nQiu et al. 2014 — Randomized Controlled Trial in Chronic Glomerulonephritis\n\nPublished in Phytotherapy Research [2], this trial is the strongest human evidence for Rehmannia's kidney-protective effects. The study enrolled 479 patients diagnosed with primary chronic glomerulonephritis (CGN) — a common cause of progressive kidney disease — and randomized them to:\n- Treatment group: Rehmannia glutinosa acteosides 400 mg/day + irbesartan 150 mg/day\n- Control group: irbesartan 150 mg/day alone\n\nDuration: 8 weeks. Primary endpoint: 24-hour urinary protein.\n\nResults:\n- Treatment group: 36.42% reduction in 24-h proteinuria from baseline (p < 0.001 vs baseline)\n- Control group: 27.97% reduction (p < 0.001 vs baseline)\n- Between-group difference: p = 0.0278, statistically significant\n- No significant between-group differences in adverse events, liver enzymes, electrolytes, or blood pressure\n\nThe 36 vs 28% difference in proteinuria reduction represents a clinically meaningful additive benefit. Urinary protein is a direct marker of glomerular damage and a predictor of disease progression to end-stage renal failure. The study's large sample size (479 patients) and randomized design make this one of the better-quality trials available for a traditional Chinese herb in a specific clinical population.\n\nLimitations include the relatively short 8-week duration, the use of combination therapy rather than Rehmannia alone, and the absence of long-term follow-up on hard outcomes like doubling of serum creatinine or dialysis initiation.\n\nZhou et al. 2015 — Rehmannia Polysaccharide in Diabetic Models\n\nPublished in the Journal of Ethnopharmacology [3], this study examined purified Rehmannia glutinosa polysaccharide (RGP) in streptozotocin (STZ)-induced diabetic mice — a well-established model of type 1-like diabetes.\n\nThe design compared diabetic untreated mice, diabetic mice receiving RGP (50, 100, or 200 mg/kg/day), and healthy controls over 4 weeks of oral treatment.\n\nKey outcomes at the 200 mg/kg dose:\n- Blood glucose: significantly reduced vs untreated diabetic mice; approached but did not reach normal control levels\n- Total cholesterol: significantly reduced (dyslipidemia is a major complication of diabetes)\n- Triglycerides: significantly reduced\n- TNF-α and IL-6 (vascular inflammation markers): significantly reduced, suggesting attenuation of the chronic low-grade inflammation driving diabetic vascular disease\n- Superoxide dismutase (SOD) activity: significantly increased, indicating improved antioxidant defense\n- Malondialdehyde: significantly reduced, indicating less oxidative damage to lipids\n\nInsulin levels in the RGP group were significantly higher than the untreated diabetic group, suggesting partial preservation or restoration of beta-cell function.\n\nThe researchers proposed that RGP acts through multiple mechanisms: direct antioxidant activity protecting islet cells, anti-inflammatory cytokine suppression reducing islet inflammation, and possible enhancement of insulin signaling in peripheral tissues.\n\nLimitations: this is an animal study using an induction model of diabetes rather than type 2 diabetes, and the dose required to demonstrate effects in mice does not translate directly to human doses. Human clinical trials specifically testing Rehmannia polysaccharide for blood sugar management have not yet been published.\n\nKim, Yook & Kim 2017 — Review of Korean Clinical Publications\n\nPublished in the Journal of Pharmacopuncture [4], this review systematically examined 30 Korean-language publications on Rehmanniae Radix published through 2017 — a body of literature largely unavailable to English-language researchers. …","deepTruncated":true,"references":[{"id":"1","title":"Rehmannia glutinosa: review of botany, chemistry and pharmacology","authors":"Zhang RX, Li MX, Jia ZP","year":2008,"journal":"Journal of Ethnopharmacology","pmid":"18407446","url":"https://pubmed.ncbi.nlm.nih.gov/18407446/"},{"id":"2","title":"Treatment of primary chronic glomerulonephritis with Rehmannia glutinosa acteosides in combination with the angiotensin receptor blocker irbesartan: a randomized controlled trial","authors":"Qiu H, Fu P, Fan W, Zuo C, Feng P, et al.","year":2014,"journal":"Phytotherapy Research","pmid":"23519822","url":"https://pubmed.ncbi.nlm.nih.gov/23519822/"},{"id":"3","title":"Rehmannia glutinosa (Gaertn.) DC. polysaccharide ameliorates hyperglycemia, hyperlipemia and vascular inflammation in streptozotocin-induced diabetic mice","authors":"Zhou J, Xu G, Yan J, Li K, Bai Z, Cheng W, Huang K","year":2015,"journal":"Journal of Ethnopharmacology","pmid":"25698243","url":"https://pubmed.ncbi.nlm.nih.gov/25698243/"},{"id":"4","title":"Rehmanniae Radix, an Effective Treatment for Patients with Various Inflammatory and Metabolic Diseases: Results from a Review of Korean Publications","authors":"Kim SH, Yook TH, Kim JU","year":2017,"journal":"Journal of Pharmacopuncture","pmid":"30087783","url":"https://pubmed.ncbi.nlm.nih.gov/30087783/"},{"id":"5","title":"Assessment of the Effect of Rehmannia glutinosa Leaf Extract in Maintaining Skin Health: A Proof-of-Concept, Double-Blind, Randomized, Placebo-Controlled Clinical Trial","authors":"Srivastava S, Huang SF, Jagtap MS","year":2024,"journal":"Clinical, Cosmetic and Investigational Dermatology","pmid":"38651075","url":"https://pubmed.ncbi.nlm.nih.gov/38651075/"}],"wordCount":2138,"source":{"path":"src/content/topics/rehmannia/kidney-adrenal-and-blood-sugar.md"},"citeAs":"“Does Rehmannia help kidney function, blood sugar and adrenal health?.” What's Healthy and Why. https://whatshealthyandwhy.com/rehmannia/kidney-adrenal-and-blood-sugar","notice":"General information backed by peer-reviewed research, not medical advice."}