Herb module
Yuan Zhi
MilkwortPolygala tenuifolia
A slightly warm root used to calm the Spirit, support memory, and link Heart and Kidney for a settled mind.
Yuan Zhi is the root of a slender Chinese milkwort and a classic herb for a restless Spirit. Traditional Chinese Medicine uses it to reconnect the Heart and the Kidney and to clear Phlegm that clouds the mind. Zoi includes it in Brain + Mood | Xýlo™ and Heart Meridian™.
Best functions
- Traditionally used to calm the Spirit (Shen) and quiet the Heart
- Used to clear the channel that joins the Heart and the Kidney
- Used to support memory and clear thinking
- Used to expel Phlegm, open the orifices, clear the Lungs, and ease coughing
- Traditionally used to dissipate swellings
Fascinating facts
- The name Yuan Zhi means "far-reaching will," a nod to its traditional role in steadying the mind and strengthening resolve.
- Traditional Chinese Medicine pictures a pathway between the Heart, home of the Spirit, and the Kidney, home of willpower. Yuan Zhi is used to keep that pathway open so the two can communicate.
- The species name "tenuifolia" means "thin-leaved." This small plant has narrow, slender leaves and delicate purple-blue flowers, and the root is the part used.
- Studies suggest Yuan Zhi may help regulate neurotransmitters and influence the stress hormone corticosterone. Research has also looked at its calming and mood-lifting effects.
In Traditional Chinese Medicine
Yuan Zhi is slightly warm in nature, with a bitter and pungent flavor. Traditional Chinese Medicine counts it among the astringent herbs, and it enters the Heart and Lung channels.
Biomedical deep dive
Yuan Zhi Milkwort
From the Zoi Medicinals fact sheets’ Biomedical Details, with lines from Noa’s herb notes marked “Noa’s notes”.
On the fact sheet
- Yuan Zhi (Milkwort, Radix Polygalae) is slightly warm and enters the HT and LU meridians. Calms the Spirit, sedates the Heart and clears the meridian joining the Heart and Kidney, expels Phlegm, opens the orifices, clear the Lungs and stops coughing, reduces abscesses and dissipates swellings. Brain + Mood | Xýlo · Heart Meridian sheets
Key active constituents
- Methyl 3,4,5-trimethoxycinnamate, a Polygala root compound named in a cited heart-rhythm study (Heart Meridian sheet references).
Pharmacology and mechanisms
- The Xýlo sheet says Yuan Zhi has shown anti-anxiety and antidepressant effects in various studies.
- The Xýlo sheet lists Yuan Zhi among herbs with strong anti-inflammatory and neuroprotective (nerve-protecting) properties.
- It has shown nerve regenerative properties and cognitive-enhancing (nootropic) properties.
- The Heart Meridian sheet says Polygalae may help regulate neurotransmitters and stress hormone (corticosterone) levels.
- Tenuigenin promotes BDNF and NGF (growth factors that support nerve cells); neurotrophic and antidepressant effects. Noa’s notes
- Inhibits acetylcholinesterase (the enzyme that breaks down the memory messenger acetylcholine); pro-cognitive in Alzheimer's models. Noa’s notes
- Anxiolytic (calming): modulates the HPA axis (the stress-hormone system) and lowers stress-induced corticosterone. Noa’s notes
What the research says
- A review of the Polygala genus supports anti-anxiety, antidepressant, nerve-regenerating and cognitive effects (Lacaille-Dubois et al., J Ethnopharmacol 2020).
- Radix Polygalae extract showed a rapid-onset antidepressant-like effect in preclinical studies (Shin et al., PLoS One 2014).
- A review covers Radix Polygalae's protective effects in neurological conditions (Jiang et al., Front Psychiatry 2021).
- A Polygala root compound suppressed abnormal electrical triggers in heart muscle cells, suggesting antiarrhythmic potential (Zhao et al., Biol Pharm Bull 2013).
Safety, interactions and cautions
- Every Zoi fact sheet: do not use if pregnant or breastfeeding unless directed by your health care practitioner.
- The Xýlo fact sheet cautions anyone with a medical condition or taking medication to consult their doctor before use.
- Avoid with gastric ulcers or gastritis; its saponins can irritate the stomach lining. Noa’s notes
In these Zoi formulas
- Brain + Mood | Xýlo (#9 on the fact sheet)
- Heart Meridian (#6 on the fact sheet)
