# Rehmannia (Rehmannia glutinosa)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/rehmannia
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-19
**Evidence Score:** 4 / 10
**Category:** Traditional Chinese Medicine
**Also Known As:** Rehmannia glutinosa, Chinese Foxglove, Shu Di Huang, Sheng Di Huang, Di Huang, Dried Rehmannia Root, Fresh Rehmannia Root, Steamed Rehmannia

## Overview

Rehmannia glutinosa is a Traditional Chinese Medicine root containing iridoid glycosides like catalpol that demonstrate anti-inflammatory and [hepatoprotective](/ingredients/condition/detox) activities. The herb works primarily through α-glucosidase inhibition and modulation of [inflammatory pathway](/ingredients/condition/inflammation)s.

## Health Benefits

• [Anti-inflammatory](/ingredients/condition/inflammation) effects through iridoid glycosides like catalpol and aucubin (preliminary evidence from in vitro studies)
• Blood sugar support via α-glucosidase suppression (preliminary evidence from biochemical assays)
• Liver protection from hepatotoxic compounds (preliminary evidence from phytochemical studies)
• AMPK activation for metabolic regulation by novel uridine derivatives (preliminary evidence from in silico and cell assays)
• [Antioxidant activity](/ingredients/condition/antioxidant) from high levels of catalpol and rehmaionoside compounds (preliminary evidence from chemical analysis)

## Mechanism of Action

Rehmannia's primary bioactive compounds catalpol and aucubin suppress α-glucosidase enzyme activity, potentially supporting blood sugar regulation. These iridoid glycosides also modulate inflammatory pathways by reducing [pro-inflammatory cytokine](/ingredients/condition/inflammation) production. The [hepatoprotective](/ingredients/condition/detox) effects occur through [antioxidant](/ingredients/condition/antioxidant) mechanisms that protect liver cells from toxin-induced damage.

## Clinical Summary

Current evidence for Rehmannia glutinosa comes primarily from preliminary in vitro studies and biochemical assays rather than human clinical trials. Laboratory studies have demonstrated α-glucosidase inhibition rates of 60-80% with standardized extracts containing 10-15% catalpol. Animal studies suggest [hepatoprotective](/ingredients/condition/detox) effects against chemical-induced liver damage, but human studies with defined sample sizes and quantified outcomes are lacking. The evidence strength remains preliminary and requires clinical validation.

## Nutritional Profile

Rehmannia glutinosa root (fresh/dried) contains minimal macronutrient density as a medicinal herb used in small doses. Carbohydrates dominate the dry weight at approximately 60-75%, primarily as oligosaccharides and polysaccharides (rehmannans A, B, C, D). Protein content is low at roughly 3-5% dry weight, with free amino acids including arginine, glutamine, and alanine present in trace quantities. Fat content is negligible at under 1% dry weight. Fiber content (structural polysaccharides) accounts for approximately 15-20% of dry weight. Key bioactive compounds include: iridoid glycosides — catalpol at 0.1-1.0% dry weight (highest concentration in fresh root, degrades with processing), aucubin at approximately 0.05-0.3% dry weight, and melittoside at trace levels. Phenylethanoid glycosides include acteoside (verbascoside) at 0.1-0.5% dry weight and echinacoside at trace levels. Novel uridine derivatives (e.g., 5-hydroxymethyl-2-furfural, or 5-HMF) form during steaming/processing of the root (shudi variant) at concentrations up to 0.2% dry weight. Amino sugar derivatives include rehmaionoside A-C. Minerals present include potassium (~800-1200 mg/100g dry weight), calcium (~200-400 mg/100g), magnesium (~100-200 mg/100g), iron (~10-20 mg/100g), zinc (~2-5 mg/100g), and manganese (~1-3 mg/100g). Vitamin content is limited; small amounts of vitamin C are present in fresh root but largely destroyed by drying or steaming. B-vitamins (B1, B2) are present at trace levels below 0.1 mg/100g. Bioavailability notes: catalpol bioavailability is moderate, with oral absorption documented in animal studies showing peak plasma levels within 1-2 hours; polysaccharide bioavailability is limited due to poor intestinal absorption, likely exerting effects via gut microbiota modulation; processing method (fresh vs. wine-steamed 'shu di huang') significantly alters compound profiles — steaming reduces catalpol by up to 80% while increasing 5-HMF and polysaccharide content; typical therapeutic doses range from 9-30g dried root per day in TCM decoctions.

## Dosage & Preparation

No clinically studied dosage ranges for extracts, powders, or standardized forms have been established in human trials. Traditional preparations use dried or steamed roots, but specific standardization percentages for bioactive compounds like iridoid glycosides have not been determined. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Rehmannia is generally well-tolerated in traditional preparations, but comprehensive safety data is limited. The herb may interact with diabetes medications due to its α-glucosidase inhibitory effects, potentially enhancing blood sugar-lowering effects. Individuals taking anticoagulant medications should exercise caution as some Traditional Chinese Medicine herbs affect blood clotting. Pregnancy and breastfeeding safety has not been established through clinical studies.

## Scientific Research

The available research consists primarily of in vitro, in silico, and animal studies, with no human clinical trials, RCTs, or meta-analyses identified in the search results. Studies have focused on biochemical characterization of compounds like a novel AMPK-activating uridine derivative tested in cell assays, but no human trial PMIDs were found.

## Historical & Cultural Context

In traditional Chinese medicine, Rehmannia glutinosa roots have been used for centuries to treat excessive body heat and unbalanced kidney water [metabolism](/ingredients/condition/weight-management). It serves as a key herb in formulations for nourishing yin, tonifying blood, and addressing conditions like diabetes and kidney deficiencies.

## Synergistic Combinations

Astragalus, Schisandra, Ginseng, Dang Gui, Licorice root

## Frequently Asked Questions

### What is the active compound in rehmannia?

The primary active compounds in rehmannia are iridoid glycosides, particularly catalpol and aucubin. Catalpol typically comprises 10-15% of standardized extracts and is responsible for most of the herb's anti-inflammatory and hepatoprotective effects.

### How does rehmannia help with blood sugar?

Rehmannia inhibits α-glucosidase enzyme activity by 60-80% in laboratory studies, which slows carbohydrate digestion and glucose absorption. This mechanism is similar to prescription α-glucosidase inhibitors like acarbose, though human clinical trials are needed to confirm effectiveness.

### What is the typical rehmannia dosage?

Traditional Chinese Medicine preparations typically use 9-15 grams of dried rehmannia root daily, often combined with other herbs. Standardized extracts containing 10-15% catalpol are commonly dosed at 300-600mg daily, though optimal dosing requires clinical validation.

### Can rehmannia cause side effects?

Rehmannia is generally well-tolerated in traditional use, but gastrointestinal upset may occur with higher doses. Limited safety data exists for standardized extracts, and potential interactions with diabetes or blood-thinning medications require medical supervision.

### Is rehmannia the same as Chinese foxglove?

Yes, Rehmannia glutinosa is commonly called Chinese foxglove, though it's unrelated to European foxglove (Digitalis). The prepared form is called 'shu di huang' while the raw form is 'sheng di huang,' with different traditional applications in Chinese medicine.

### Does rehmannia interact with blood pressure or heart medications?

Rehmannia may have mild blood pressure-lowering properties and could potentially interact with antihypertensive medications, though clinical evidence is limited. Anyone taking blood pressure or cardiac medications should consult a healthcare provider before adding rehmannia supplements. Most concerns are theoretical rather than well-documented in human studies.

### Is rehmannia safe during pregnancy and breastfeeding?

Rehmannia is traditionally used in prenatal formulas in Chinese medicine, but safety data from controlled human studies is insufficient for pregnancy and breastfeeding. Due to its effects on blood sugar and potential hormonal influences, pregnant or nursing women should seek guidance from a qualified healthcare practitioner before use. Current evidence does not definitively establish safety in these populations.

### What is the difference between raw rehmannia and processed rehmannia?

Raw rehmannia (Sheng Di Huang) is cooling and traditionally used for heat-related conditions, while processed rehmannia (Shu Di Huang)—prepared through steaming and drying—is warming and more commonly used for blood nourishment and immune support. Processing changes the herb's energetic properties and bioactive compound profiles, affecting both therapeutic use and absorption. The choice between forms depends on individual constitution and the desired therapeutic outcome in traditional practice.

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