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Limited evidenceSleep & relaxation

Honokiol

A biphenyl compound from magnolia bark with a clear sedative mechanism in animals. No human trial has tested isolated honokiol for sleep or anxiety; the only clinical data come from whole magnolia bark blends.

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What the science says

  • Promotes non-REM sleep in animals Limited evidence

    A controlled mouse study showed that honokiol increases non-rapid-eye-movement sleep and shortens sleep latency, and that the effect is blocked by flumazenil, indicating action at the benzodiazepine site of the GABA-A receptor. This is a well-characterised mechanism but was demonstrated only in rodents.

  • Stress and cortisol in humans Limited evidence

    A small pilot double-blind placebo-controlled trial in healthy women found modest reductions in self-reported stress with a proprietary magnolia and phellodendron bark extract. The product was a multi-ingredient blend rather than isolated honokiol, so the contribution of honokiol itself cannot be separated.

  • Anxiety reduction Limited evidence

    No randomised trial has measured validated anxiety scales with purified honokiol in people. The anxiolytic reputation is extrapolated from receptor binding data and rodent behavioural models.

Dosage & safety

Studied doseNo established human dose for isolated honokiol. Magnolia bark extracts used in human studies supplied roughly 250–750 mg per day of combined bark extract; supplements standardised to honokiol commonly list 100–250 mg per day as a label dose.
SafetyHuman safety data are limited to short pilot trials of bark blends, where side effects were mild. Because honokiol acts at the benzodiazepine site, do not combine it with alcohol, benzodiazepines, z-drugs or other sedatives, and do not drive after taking it until you know how it affects you. Avoid in pregnancy and breastfeeding; caution with anticoagulants given reported antiplatelet activity.

How to take it

TimingEvening only, 30-60 minutes before bed - the sedative effect makes daytime dosing a poor idea.
With food?With or without food, though honokiol is fat-soluble and a meal containing fat likely improves absorption.
Worth knowingTreat the first dose like a new sleep medication: take it on a night when you have nowhere to be the next morning.

Interactions

With medications

  • benzodiazepines, z-drugs, opioids, sedating antihistamines and alcohol

    Honokiol potentiates GABA-A receptors at the benzodiazepine site, so sedation and impairment are additive. do not combine, and do not drive after taking it until you know how it affects you

  • warfarin, direct oral anticoagulants and antiplatelets

    Antiplatelet activity has been reported for magnolia bark constituents, adding to bleeding risk. tell your prescriber before starting and stop two weeks before surgery

With other supplements

  • valerian, kava, melatonin and other sedative supplements

    Additive sedation through overlapping GABAergic mechanisms. use one at a time

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does honokiol help you sleep?

Honokiol has limited evidence: in mice it increased non-REM sleep and shortened sleep latency through the benzodiazepine site of the GABA-A receptor, but no human trial has tested isolated honokiol for sleep.

Does honokiol reduce stress or anxiety?

The only human data come from a small pilot trial in which a magnolia and phellodendron bark blend modestly reduced self-reported stress in healthy women, so honokiol's own contribution is unknown. No randomised trial has measured anxiety with purified honokiol.

Is honokiol safe to take with sleeping pills?

No. Honokiol acts at the same benzodiazepine site of the GABA-A receptor, so do not combine it with benzodiazepines, z-drugs, opioids, sedating antihistamines or alcohol, and do not drive after taking it until you know how it affects you.

How much honokiol should I take?

There is no established human dose for isolated honokiol; supplements commonly list 100-250 mg per day, and human studies of magnolia bark extracts used roughly 250-750 mg per day of combined extract. Take it only in the evening.

Scientific references

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