Home Ingredients Polygala (Yuan Zhi)
CognitiveMood & Mental Health

Polygala (Yuan Zhi)

Polygala tenuifolia
Evidence Level
Moderate
3 Clinical Trials
5 Documented Benefits
3/5 Evidence Score

Polygala (yuan zhi) is a Chinese herb used as a calming and cognitive tonic, traditionally to calm the spirit and support memory, sleep, and a settled mind. It is a classic herb in formulas for mood and cognition and is studied for neuroprotective and mood-related effects. The prepared root is used within traditional formulas or as an extract, under product or practitioner guidance. Polygala is generally considered safe within traditional practice, though raw polygala can irritate the stomach, so it is usually processed to reduce this; those with ulcers or gastritis should use caution and consult a practitioner or doctor.

Studied Dose BT-11 standardized extract 200-300 mg 3×/day (600-900 mg/day); traditional 3-9 g/day dried root or 200-1,000 mg/day powdered.
Active Compound Tenuigenin (tenuifolin; primary active sapogenin), polygalasaponins (XXXII/PGS32 most studied), tenuifoliside B (acylated oligosaccharide), onjisaponin B, sinapic acid esters.

Benefits

Memory enhancement in healthy adults (BT-11 RCT)

A randomized double-blind placebo-controlled parallel-group study in healthy adults given BT-11 (Polygala tenuifolia root extract) capsules found BT-11 improved verbal and working memory vs placebo. A foundational human trial supporting the cognitive enhancement claim.

Supported by Trial 1, Trial 2

Cognitive enhancement in elderly (BT-11 RCT)

A randomized double-blind placebo-controlled comparison in elderly adults given BT-11 vs placebo found total CERAD scores significantly more increased in the BT-11 group than placebo. This extends the cognitive benefit to an elderly population — directly relevant to age-related cognitive decline.

Supported by Trial 2

Alzheimer's disease (TCM combination evidence)

A systematic review of Polygala tenuifolia + Acorus tatarinowii combination for Alzheimer's disease pooled multiple Chinese RCTs (outcomes: MMSE, ADL, ADAS-cog) and showed efficacy improvements over control. Limited by Chinese RCT methodology concerns and combination-product attribution, but provides supporting context for TCM cognitive use.

Supported by Trial 3

Sedative and anxiolytic activity (traditional)

TCM uses Polygala for insomnia, palpitations, restlessness, and anxiety — alongside cognitive enhancement, an unusual combination of indications. Mechanistically supported by polygalasaponin GABA-modulating activity. Limited human RCT evidence specifically for anxiety/sleep but consistent traditional use across centuries.

Supported by Trial 3, Trial 1

Neuroprotection (preclinical evidence)

Tenuigenin, tenuifolin, polygalasaponins, and onjisaponin B demonstrate β-amyloid reduction, antioxidant effects, neurotransmitter regulation, synaptic function improvement, anti-inflammatory effects, neuronal apoptosis inhibition, and autophagy modulation in animal models of dementia, Alzheimer's, and Parkinson's. The mechanistic foundation is stronger than the human RCT base.

Supported by Trial 1, Trial 3

Mechanism of action

1

Acetylcholinesterase inhibition (cholinergic enhancement)

Polygala tenuifolia extract demonstrates acetylcholinesterase inhibitory activity in vitro — increasing synaptic acetylcholine availability. Mechanism comparable to (but weaker than) donepezil-class Alzheimer's drugs. Supports cognitive enhancement claims via cholinergic pathway involved in encoding new information.

2

BDNF and MAP kinase pathway activation

Polygalasaponin XXXII (PGS32) and other actives activate ERK/CREB pathway leading to elevated brain-derived neurotrophic factor (BDNF) — key for synaptic plasticity, neurogenesis, and cognitive function. Long-term potentiation (LTP) enhancement in dentate gyrus electrophysiology. Mechanism for sustained cognitive benefit beyond acute cholinesterase inhibition.

3

GABA-modulating activity (sedative effects)

Polygalasaponins extract shows GABAergic modulation — anxiolytic and sedative-hypnotic activities in animal models. Mechanism for traditional sedative/anti-anxiety uses. May cause mild sedation in some users — consistent with TCM use for insomnia and 'calming the heart-spirit.'

4

Nerve growth factor (NGF) release enhancement

P. tenuifolia extract enhances NGF release from astroglial cells — supporting neuronal survival, growth, and synaptic maintenance. Combined with BDNF effects, produces broader neurotrophic support relevant to age-related cognitive decline and dementia prevention. Direct human translation limited.

Clinical trials

1
BT-11 Memory in Healthy Adults (Pivotal)

Randomized double-blind placebo-controlled parallel-group study (Lee JY, Kim KY, Shin KY, Won BY, Jung HY, Suh YH 2009, Phytomedicine 16(8):700-704, doi:10.1016/j.phymed.2009.04.001).

Healthy Korean adults received BT-11 (Polygala tenuifolia Willdenow root extract) capsules or placebo 3 times daily for 4 weeks. Korean version of California Verbal Learning Test (K-CVLT) for verbal memory and Self-Ordered Pointing Test (SOPT) for working memory.

BT-11 enhanced memory in healthy humans vs placebo on cognitive testing. Foundational positive trial demonstrating cognitive enhancement effect of standardized P. tenuifolia extract in cognitively normal adults. Translates extensive preclinical animal evidence (scopolamine-/stress-induced amnesia models) to humans.

2
BT-11 in Elderly Cognitive Function

Randomized double-blind placebo-controlled comparison (Shin KY, Lee JY, Won BY, Jung HY, Chang KA, Koppula S, Suh YH 2009, Phytother Res 23(11):1561-1564, doi:10.1002/ptr.2802).

Elderly humans randomized to BT-11 (n=28) or placebo (n=25). Used CERAD (Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet) and MMSE assessments.

Total CERAD scores significantly more increased in BT-11-treated group than in placebo group. Demonstrates cognitive enhancement extends to elderly population — most relevant clinical context for age-related cognitive decline applications. Replicates and extends Lee 2009 healthy adult finding.

3
P. tenuifolia + A. tatarinowii in Alzheimer's Evidence Synthesis

Evidence review and pooled analysis (Zhang Y, Tian J, Ni J, Wei M, Li T, Shi J 2024, Front Pharmacol 14:1268000, doi:10.3389/fphar.2023.1268000). PROSPERO registered.

Evidence review of Chinese clinical trials of Polygala tenuifolia + Acorus tatarinowii combination treatment for Alzheimer's disease. 8 databases searched. Outcomes: MMSE, ADL, ADAS-cog. Cochrane risk of bias assessment.

Combination improved cognitive measures (MMSE, ADAS-cog) and functional measures (ADL) in pooled analysis. Limited by methodological quality concerns of Chinese clinical trials and combination-product attribution. Provides evidence review evidence for the most common TCM cognitive combination using Polygala.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated at studied doses; few adverse events in Lee/Shin trials.
Mild GI upset, nausea at high doses — particularly notorious for irritating gastric mucosa due to saponin content.
Mild sedation in some users.
Rare allergic reactions.
Pregnancy: avoid — traditional contraindication, possible uterine effects.
Long-term safety beyond 12 weeks: limited data.

Important Drug interactions

Cholinesterase inhibitors (donepezil, rivastigmine, galantamine): theoretical additive cholinergic effects.
Sedatives/CNS depressants: theoretical additive sedation.
Antidepressants: theoretical interactions; clinical relevance unclear.
Anticoagulants: theoretical mild antiplatelet effect.
Most medications: no significant clinical interactions documented at typical doses.

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Frequently asked questions about Polygala (Yuan Zhi)

What is polygala used for?

Polygala (yuan zhi) is a Chinese herb used as a calming and cognitive tonic, traditionally to calm the spirit and support memory, sleep, and a settled mind. It is a classic herb for mood and cognition in TCM.

What is polygala good for?

It is traditionally used for memory and mental clarity, calming anxiety and supporting sleep, and is studied for neuroprotective and mood-related effects. It is usually used within formulas.

How much polygala should I take?

It is used within traditional formulas or as an extract; follow product or practitioner guidance. The prepared root is the part used.

Is polygala safe?

Within traditional practice it is generally considered safe. Raw polygala can irritate the stomach, so it is usually prepared (processed) to reduce this. Those with ulcers or gastritis should use caution; check with a practitioner or doctor.

What is Polygala?

Polygala (yuan zhi) is a Chinese herb used as a calming and cognitive tonic, traditionally to calm the spirit and support memory, sleep, and a settled mind. It is a classic herb in formulas for mood and cognition and is studied for neuroprotective and mood-related effects.

What is the recommended dosage of Polygala?

The clinically studied dose is BT-11 standardized extract 200-300 mg 3×/day (600-900 mg/day); traditional 3-9 g/day dried root or 200-1,000 mg/day powdered. Always follow the product label and check with a healthcare provider for personal advice.

Is Polygala safe, and does it have side effects?

For most healthy adults, Polygala is well tolerated at studied doses. Reported effects can include: Generally well-tolerated at studied doses; few adverse events in Lee/Shin trials. Mild GI upset, nausea at high doses — particularly notorious for irritating gastric mucosa due to saponin content. It may also interact with some medications. Polygala is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Polygala interact with any medications?

Possible interactions include: Cholinesterase inhibitors (donepezil, rivastigmine, galantamine): theoretical additive cholinergic effects. Sedatives/CNS depressants: theoretical additive sedation. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Polygala?

NutraSmarts rates the evidence for Polygala as Moderate (3 out of 5). It is backed by 3 clinical trials and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Zhao X, Cui Y, Wu P, Zhao P, Zhou Q, Zhang Z, et al. Polygalae Radix: A review of its traditional uses, phytochemistry, pharmacology, toxicology, and pharmacokinetics. Fitoterapia. 2020;147:104759. doi: 10.1016/j.fitote.2020.104759.PubMedUsed to support: A review of Polygalae Radix (Polygala) traditional uses, phytochemistry, and pharmacology, including cognitive and calming actions.
  2. Chen Z, Yang Y, Han Y, Wang X Neuroprotective Effects and Mechanisms of Senegenin, an Effective Compound Originated From the Roots of Polygala Tenuifolia. Frontiers in Pharmacology. 2022;13:937333. doi: 10.3389/fphar.2022.937333.PubMedUsed to support: A study of the neuroprotective mechanisms of senegenin, an active constituent of Polygala, supporting its cognitive positioning.
  3. Hong F, Wang L, Wu SL, Tang HC, Sha O, Wai MSM, et al. A Review of Three Commonly Used Herbs Which Enhance Memory and New Evidences Which Show Their Combination Could Improve Memory in Young Animals. Mini Reviews in Medicinal Chemistry. 2017;17(16):1537-1547. doi: 10.2174/1389557516666160919164352.PubMedUsed to support: A review of memory-enhancing herbs including Polygala, summarizing the cognitive rationale.