Magnolia Bark (Honokiol)
Honokiol is a bioactive lignan from magnolia bark, used in traditional medicine and supplements for anxiety, stress and sleep. It positively modulates GABA-A receptors at a site distinct from benzodiazepines and shows anxiolytic and sleep-promoting effects in animals. Human evidence is limited to small studies and combination products, largely for stress and cortisol.
01 Overview
Magnolia bark contains honokiol and magnolol. Preclinical work shows honokiol enhances GABA-A receptor currents, promotes non-REM sleep and reduces anxiety-like behaviour, with an anxiolytic profile said to carry less sedation and motor impairment than benzodiazepines in animals.
Human data are thin: most trials use magnolia combined with other botanicals (for example with Phellodendron) for stress and perceived cortisol effects. It is generally well tolerated in short-term use, though robust safety and efficacy data are lacking.
02 Mechanism
Honokiol acts as a positive allosteric modulator of GABA-A receptors at a benzodiazepine-independent site, enhancing chloride currents; it also has antioxidant and anti-inflammatory actions.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Stress / sleep (extract) | 200–400 mg/day | Oral | Magnolia bark extract; honokiol content varies by product. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| AnxiolysisReduces anxiety-like behaviour via GABA-A modulation in preclinical models. | Moderate in animals | Preclinical | |
| Improved sleep / relaxationReported easier sleep and reduced tension; supported mainly by animal data and small combination studies. | Reported | Anecdotal |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| DrowsinessSedation, particularly at higher doses or with other depressants. | Mild | Uncommon | Anecdotal | |
| Gastrointestinal upsetOccasional nausea or stomach discomfort. | Mild | Rare | Anecdotal |