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Rehmannia Root

Also known as: Rehmannia root, Chinese foxglove root, Rehmannia glutinosa

Overview

Rehmannia root, derived from the dried root of Rehmannia glutinosa, is a prominent herb in Traditional Chinese Medicine (TCM). It is available in raw or processed forms, with processed forms often preferred for specific therapeutic effects. Traditionally, it has been used for a range of conditions including gynecological issues, diabetes, diabetic nephropathy, and perimenopausal syndrome, as well as for general vitality. The herb's therapeutic properties are attributed to a complex mixture of bioactive compounds, primarily iridoid glycosides like catalpol, along with phenylethanoid glycosides and nucleosides. While research maturity is moderate with a growing number of randomized controlled trials and meta-analyses, particularly in Chinese populations, high-quality Western RCTs are still limited. The evidence quality varies, with existing systematic reviews often including studies with moderate risk of bias and heterogeneity.

Benefits

Rehmannia root offers several evidence-based benefits. For perimenopausal syndrome (PMS), particularly in breast cancer patients, a 2025 systematic review and meta-analysis of 17 RCTs (n=1,139) found that Chinese herbal medicine (CHM) containing Rehmannia glutinosa significantly improved menopausal symptoms, immune markers (CD4/CD8 ratio), and Karnofsky performance scores compared to Western medicine controls. Processed Rehmannia root has shown potential to improve ovarian hypofunction, diminished ovarian reserve, and premature ovarian insufficiency, likely by modulating glycoside compounds that affect ovarian aging pathways. In the context of diabetic nephropathy, catalpol, a key active compound, demonstrated protective effects in animal models by improving renal function and reducing oxidative stress and inflammation, suggesting its potential for managing diabetes-related kidney disease. While network pharmacology studies suggest multi-target effects on anxiety-related pathways, clinical evidence for anxiety disorders is currently lacking.

How it works

The therapeutic actions of Rehmannia root are primarily mediated by its main bioactive compound, catalpol, which exhibits anti-inflammatory, antioxidant, and immunomodulatory effects. Rehmannia root modulates immune cell populations, specifically increasing CD4+ T cells and improving the CD4/CD8 ratio, which is beneficial for immune function. It also influences gonadal hormone levels and affects signaling pathways crucial for ovarian function and in the progression of diabetic nephropathy. Molecular docking studies indicate that active compounds within Rehmannia root, such as stigmasterol and beta-sitosterol, interact with targets like nitric oxide synthase 3 (NOS3), suggesting roles in vascular and neural function. The processing of the root significantly alters its glycoside profiles, which in turn impacts its pharmacological activity and bioavailability, leading to different therapeutic outcomes.

Side effects

Rehmannia root is generally well tolerated, with meta-analyses of clinical trials reporting no severe adverse events. When side effects do occur, they are typically rare and mild, primarily involving gastrointestinal discomfort. While no significant drug interactions or contraindications have been firmly established, caution is advised for pregnant or breastfeeding women due to limited research in these populations. The safety of Rehmannia root in long-term use also requires further investigation to fully understand any potential cumulative effects. Overall, its safety profile appears favorable in the studied clinical contexts, particularly when used as part of multi-herb formulas.

Dosage

Dosage guidelines for Rehmannia root are not yet standardized, as clinical trials often incorporate it as part of multi-herb formulas rather than as an isolated extract. Traditional use and research frequently utilize processed forms of the root in decoctions or extracts, with standardization sometimes based on catalpol content. The specific minimum effective doses are not well-defined, and the timing and form (raw versus processed) can significantly influence both efficacy and safety. For gynecological indications, processed forms are generally preferred. Due to the variability in formulations and the lack of standardized single-ingredient dosing, it is advisable to follow the recommendations of a qualified healthcare practitioner or the specific instructions provided with a standardized product.

FAQs

Is Rehmannia root safe for breast cancer patients?

Yes, clinical data in breast cancer patients with perimenopausal syndrome indicate that Rehmannia root, often as part of Chinese herbal medicine, is safe and effective without severe adverse effects.

How quickly do benefits appear?

Symptom improvements, particularly in perimenopausal syndrome, have been observed within typical trial durations, which generally range from several weeks to a few months.

Can Rehmannia root be used alone?

Most of the existing evidence supports the use of Rehmannia root in combination with other herbs within Traditional Chinese Medicine formulas, rather than as a single isolated agent.

Research Sources

https://pmc.ncbi.nlm.nih.gov/articles/PMC12251504/ – This systematic review and meta-analysis of 17 RCTs (n=1,139) found that Chinese herbal medicine containing Rehmannia glutinosa significantly improved menopausal symptoms (Kupperman index MD -12.79, p<0.01), immune markers, and performance status in breast cancer patients with perimenopausal syndrome, with no severe adverse events. The study highlights the efficacy and safety of Rehmannia-containing formulas in this specific population, though it notes some heterogeneity and a predominance of Chinese trials.
https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2024.1426972/full – This narrative review discusses how the processing of Rehmannia root alters its glycoside content, which in turn impacts its pharmacological activity. It explores potential mechanisms by which iridoid glycosides from Rehmannia may improve ovarian function, particularly in conditions like diminished ovarian reserve and premature ovarian insufficiency, primarily based on preclinical and pharmacological data.
https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2023.1192694/full – This systematic review and meta-analysis of 12 animal studies (n=231) demonstrated that catalpol, a major active compound in Rehmannia root, improved markers of diabetic nephropathy, reduced oxidative stress, and decreased inflammation in animal models. The findings suggest a protective role for catalpol in diabetes-related kidney disease, though the translation of these animal findings to human clinical outcomes remains uncertain.
https://apm.amegroups.org/article/view/65991/html – This article discusses network pharmacology studies suggesting multi-target effects of Rehmannia root compounds, such as stigmasterol and beta-sitosterol, on molecular pathways related to anxiety. It also mentions molecular docking studies indicating interactions with targets like nitric oxide synthase 3 (NOS3), relevant to vascular and neural function, providing insights into potential mechanisms of action beyond its traditional uses.
https://pubmed.ncbi.nlm.nih.gov/40628433/ – This PubMed entry corresponds to the same systematic review and meta-analysis by Kong et al. (2025) that found Chinese herbal medicine with Rehmannia glutinosa significantly improved menopausal symptoms, immune markers, and performance status in breast cancer patients with perimenopausal syndrome, confirming its safety and efficacy in this group.