Polygala tenuifolia Root Extract


Polygalae Radix | Yuan zhi | Onji


Supports cognitive function*
Supports a healthy stress response*
Supports sleep*
Supports mood*


In Traditional Chinese Medicine, Polygala tenuifolia root is one of the most used herbs to support the brain and central nervous system. Traditionally it was often used to reduce forgetfulness and support brain performance during aging (i.e., it’s what we’d consider a nootropic today). It was also commonly used in formulas to support sleep and promote a calmer, more balanced mood. Preclinical research suggests it supports brain protection and repair processes and molecules (such as BDNF and NGF), counters chronic stress, supports sleep, and influences both adenosine signaling—a molecule involved in the sleep homeostatic drive—and GABA signaling—a neurotransmitter involved with relaxation at night and sleep. The roots have several bioactive compounds thought to be relatively unique to this plant including tenuigenin, tenuifolin, yuanzhi-1, tenuifolisides, and tenuifolioses.


Polygala tenuifolia root extract is a 10:1 extract, which means that 10 parts of the root are used to create 1 part of the extract. This concentrates the active compounds, so less of the herb is needed.

Polygala tenuifolia root extract is Non-GMO and Vegan.


Because preclinical research suggests the potential for adaptogenic properties of Polygala tenuifolia, we consider dosing to follow hormetic principles similar to herbal adaptogens (see Neurohacker Dosing Principles). Herbal adaptogens tend to have a hormetic zone (or range) where there’s a favorable biological response. It’s important to be in this zone; it’s just as important not to be above it. Based on human studies and traditional uses, we’d consider the dose range for concentrated extracts to be about 100-300 mg daily (about 1-3 grams of crude root powder). Our goal with P. tenuifolia, as with all ingredient choices, is to select the appropriate dose keeping in mind both the ingredient and the other ingredients being used in a formulation. In other words, if we are also supplying other adaptogens and nootropic extracts, we are likely to dose P. tenuifolia towards the lower end of the range. 


Brain function

Supports learning and memory [1–4]

Supports sleep [5–7]

Supports glutamate decarboxylase (GAD) activity [8]

Supports GABA-Glutamate signaling [6,8–10]

Supports adenosine signaling [11]

Supports adrenergic signaling [3,5,6]

Supports dopamine signaling [3,12]

Downregulates acetylcholinesterase (AChE) activity [3,4,13]

Downregulates monoamine oxidase (MAO) [4]

Supports brain-derived neurotrophic factor (BDNF) [14,15]

Supports synaptic transmission in the hippocampus [15]

Supports long-term potentiation (LTP)/synaptic plasticity [13,15]

Supports the proliferation and differentiation of neural stem cells [16,17]

Supports neuroprotective functions

Protects against neurotoxic agents [18–20]

Protects from cognitive impairments [15,18–23]

Supports antioxidant defenses [4,13,20,24]


Supports healthy behavioral and physiological responses to stress [7,10,14]

Gut microbiota

Supports the composition of the gut microbiota [25]

Immune System

Supports adaptive immunity [26]

Supports macrophage functions [27]

Healthy aging and longevity

Supports mitochondrial function [22]


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