Rehmannia
Useful mainly for people using traditional Chinese medicine formulas and accepting limited modern evidence.
Quick decision guide
May help most
people using traditional Chinese medicine formulas and accepting limited modern evidence
Common dosing range
500–1,500 mg/day standardized extract; 9–30 g/day dried prepared root in TCM decoctions
When to expect effects
Weeks
Watch out for
Raw (unprepared) form is 'cold' in TCM and more likely to cause loose stools; human evidence is limited
What is it
Rehmannia refers to Rehmannia glutinosa (Chinese foxglove, dihuang), a perennial flowering plant in the Orobanchaceae family whose root is one of the most widely used herbs in traditional Chinese medicine. Three forms are distinguished in TCM and supplements: fresh (xian dihuang), dried/raw (sheng dihuang), and steamed/prepared (shu dihuang or radix rehmanniae preparata); the steamed form is darker, sweeter, and considered tonic for blood and yin. Key constituents include iridoid glycosides (catalpol and rehmannioside A-D), phenylethanoid glycosides (acteoside/verbascoside, echinacoside), polysaccharides, and stachyose. Rehmannia is a principal ingredient in classical formulas such as Liu Wei Di Huang Wan.
Is it worth it for you?
Use this as a quick fit check, not a diagnosis.
Worth considering if…
Probably skip if…
Evidence at a glance
| Goal | Effect | Best fit | Time |
|---|---|---|---|
type 2 diabetes (adjunct) Mixed Evidence | Modest / uncertain | adults using TCM formulas alongside standard diabetes care | Weeks |
anti-inflammatory and autoimmune support Mixed Evidence | Unclear | research-interested users; not a routine indication | Unclear |
type 2 diabetes (adjunct)
- Effect
- Modest / uncertain
- Best fit
- adults using TCM formulas alongside standard diabetes care
- Time
- Weeks
anti-inflammatory and autoimmune support
- Effect
- Unclear
- Best fit
- research-interested users; not a routine indication
- Time
- Unclear
Evidence for 2 uses
AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.
type 2 diabetes (adjunct)
Biomarker supportSome small trials, often of multi-herb formulas containing rehmannia, report modest improvements in glycemic markers, with preclinical work pointing to iridoid glycosides such as catalpol. It is difficult to attribute effects to rehmannia specifically rather than the whole formula. Endpoints are glucose biomarkers, not diabetes complications.
Bottom line: Rehmannia-containing formulas may modestly affect glucose markers, but the evidence is weak and formula-dependent.
Evidence is mixed
Most data come from multi-herb formulas, so rehmannia's individual contribution and reproducibility are unclear.
anti-inflammatory and autoimmune support
Mechanism onlyIridoid and phenylethanoid glycosides in rehmannia (catalpol, acteoside) show anti-inflammatory and immune-modulating activity in lab and animal models. Human clinical evidence for autoimmune or inflammatory conditions is essentially absent. This is a mechanistic rationale only.
Bottom line: Anti-inflammatory effects are preclinical and mechanistic, with no established human benefit.
How to take it
What to track
Safety
Know the common side effects, key cautions, and who should avoid it.
Common side effects
Who should avoid it
- People with low digestive function (especially raw form)
- Pregnant or breastfeeding women (raw form; prepared form only per traditional guidance)
- Those on anticoagulants or antidiabetic drugs without supervision (theoretical)
Pregnancy & breastfeeding
Not established; traditional sources use the prepared form in some pregnancy formulas but caution against the raw form.
Interactions
Theoretical effect suggested by preclinical data; not well documented clinically
Possible additive glucose lowering suggested by preclinical data
Choosing a product
What to look for on the label — and what to be skeptical of.
Look for…
Be skeptical of…
References by claim
Track Rehmannia with Pilora
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Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.