Polygala tenuifolia (Yuan Zhi)
What it is
A TCM herb classified as a Shen (spirit) calming and intelligence-boosting remedy for over 2,000 years. Contains tenuifolin and onjisaponins that cross the blood-brain barrier and enhance BDNF expression in animal models. A 2024 small RCT found 100 mg/day improved verbal memory in healthy older adults. May cause GI irritation at higher doses. Traditional formulas pair it with Acorus and Poria.
Dose
100–300 mg/day root extract standardised to tenuifolin; traditional decoction 3–9 g/day
Time of day & tips
Start at 100 mg/day to assess GI tolerance. Take with food. Traditional practice wraps the root in licorice to reduce stomach irritation. Allow 4–8 weeks for nootropic effects.
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