Limited evidenceBrain & cognition

Uncaria Rhynchophylla (Gou Teng)

A Chinese herb used traditionally for tremor, convulsions and hypertension, and best known in the West as an ingredient of the Kampo formula yokukansan. As a single herb, its human evidence is essentially absent.

Evidence last reviewed: August 2026

What the science says

Neuroprotective activity is preclinical only Limited evidence
Pharmacological reviews describe rhynchophylline and related indole alkaloids acting on NMDA receptors, calcium channels and neuroinflammation in cell and rodent models. No randomized trial has tested the isolated herb for calm, memory or neuroprotection in humans.
Human use comes from multi-herb formulas Limited evidence
Nearly all clinical data involving this herb come from combination prescriptions such as yokukansan, where its individual contribution cannot be separated. Ethnopharmacological reviews note this gap explicitly.

Dosage & safety

Studied doseTraditional decoctions use 3–12 g of the dried hooked stem per day, added late in cooking. No supplement dose has been validated in trials.

SafetyHuman safety data are limited. Alkaloids in the plant can lower blood pressure and may interact with antihypertensives and sedatives. Avoid in pregnancy and while breastfeeding.

Scientific references

Uncaria rhynchophylla: an ethnopharmacological review integrating traditional Chinese medicine uses with phytochemical and pharmacological evidence
Liu T, Ren W, Geng X — Front Pharmacol, 2026
Uncaria rhynchophylla and its Major Constituents on Central Nervous System: A Review on Their Pharmacological Actions
Yang W, Ip SP, Liu L — Curr Vasc Pharmacol, 2020

Where to buy

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