Home Ingredients Honokiol (Magnolia officinalis Bark)
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Honokiol (Magnolia officinalis Bark)

Magnolia officinalis Rehder & E.H. Wilson (Hou Po)
Evidence Level
Limited
3 Clinical Trials
8 Documented Benefits
2/5 Evidence Score

Honokiol is a bi-phenolic natural compound from the bark and seed cones of Magnolia officinalis — used in Traditional Chinese Medicine for over two millennia under the name 'hou po' to regulate Qi. It's a positional isomer of magnolol, with both compounds typically present together in magnolia bark extracts. Mechanistically, honokiol acts as a positive allosteric modulator of GABA-A receptors at both synaptic and extra-synaptic sites — a distinct binding mechanism from benzodiazepines. Clinical evidence supports anxiety reduction and improved sleep quality, primarily from trials using Relora® (a magnolia + phellodendron combination product) rather than purified honokiol. Strong preclinical anti-cancer evidence exists across multiple tumor types, but human cancer trials are notably absent — an important honest counter to enthusiastic marketing claims. The honest framing: a credible GABAergic anxiolytic and sleep aid backed by small but reasonable clinical trials; the anti-cancer claims are mechanistically interesting but unsupported by human evidence. Mouse kidney toxicology data warrants caution at higher doses or extended use.

Studied Dose Purified honokiol 250 mg 1-2x daily; Relora (magnolia + phellodendron) 250-300 mg 2-3x daily.
Active Compound Honokiol (3',5-di-2-propenyl-1,1'-biphenyl-2,4'-diol), a bi-phenolic compound; positional isomer of magnolol (5,5'-diallyl-2,2'-dihydroxybiphenyl); both present in magnolia bark extracts.

Benefits

Anxiety reduction in premenopausal women

In healthy overweight premenopausal women, Relora® (a magnolia + phellodendron combination) at 250 mg three times daily reduced anxiety on standardized scales, plus changes in salivary amylase and cortisol. Note: this was a combination product, not purified honokiol.

Supported by Trial 1

Anxiety and sleep improvement

Multiple small clinical studies of magnolia extracts (including Relora®) show reduced temporary anxiety and improved sleep quality. Preliminary clinical signal that motivates ongoing research interest — dedicated large-scale honokiol-specific trials are still lacking.

Supported by Trial 3, Trial 1

Cortisol and DHEA modulation

Preliminary data from Relora® studies suggest morning cortisol reduction with DHEA elevation — mechanistically aligned with HPA-axis modulation. Unpublished or limited-published data; interpretation cautious pending peer review.

Supported by Trial 1

Stress-related body weight changes

Some clinical data from Relora® trials suggest effects on stress-related body weight changes. Suggests a specific population (stress-related eating in women) where the combination may be most relevant. Modest evidence.

Supported by Trial 1, Trial 2

GABA-A receptor modulation (mechanism)

Honokiol and magnolol both act as positive allosteric modulators of synaptic and extra-synaptic GABA-A receptors. Mechanism is distinct from the benzodiazepine binding site, with sensitivity to GABA-A subunit heterogeneity. The pharmacological basis for the anxiolytic and sleep effects.

Supported by Trial 2

Anti-cancer preclinical evidence

Extensive preclinical anti-cancer evidence across lung, breast, prostate, leukemia, melanoma, glioblastoma, and other cancer cell lines and mouse models — antitumor and antiangiogenic effects. Important honest counter-evidence: no human cancer clinical trials registered after 20+ years of preclinical research. Reality check on enthusiastic anti-cancer marketing.

Supported by Trial 2

Neuroprotective effects (preclinical)

Neuroprotective evidence in Alzheimer's mouse models (LPS-induced and amyloid-β oligomer-induced neuronal damage) through antioxidant and anti-apoptotic mechanisms. Preclinical only — human neuroprotection has not been demonstrated.

Supported by Trial 2

Anti-inflammatory effects (preclinical)

Reduces TNF-α and IL-8 in immune cell models, with broader anti-inflammatory signals across preclinical models. Mechanistic complement to the GABAergic and HPA-axis effects underlying the anxiety and sleep benefits.

Supported by Trial 1, Trial 3

Mechanism of action

1

GABA-A receptor positive allosteric modulation (synaptic + extra-synaptic)

Magnolol and honokiol are positive allosteric modulators of both synaptic and extra-synaptic GABA-A receptors. Mechanism is distinct from the benzodiazepine binding site, with subunit heterogeneity sensitivity. Both fast inhibitory neurotransmission (synaptic) and tonic inhibition (extra-synaptic) are modulated — broader than typical benzodiazepine effects.

2

Cortisol / HPA axis modulation

Honokiol shows salivary cortisol effects; preliminary Relora data shows morning cortisol modulation and DHEA elevation. HPA-axis stress response modulation complements the GABAergic mechanism.

3

Anti-inflammatory NF-κB pathway

Honokiol suppresses NF-κB signaling and reduces inflammatory cytokines (TNF-α, IL-8) — broad anti-inflammatory mechanism shared with many natural-product compounds.

4

Antioxidant + anti-apoptotic neuronal protection (preclinical)

Multi-mechanism preclinical neuroprotection: antioxidant activity plus anti-apoptotic effects in neuronal cell models, including Alzheimer's mouse models. Mechanistic basis for the neuroprotective research interest.

5

Anti-cancer multi-pathway preclinical

Multiple preclinical anti-cancer pathways: angiogenesis inhibition, apoptosis induction, cell cycle arrest, multi-pathway signaling effects across cancer types. Promising in vitro and animal-model activity that has not yet translated to human cancer trials.

6

Antimicrobial activity

Honokiol shows antimicrobial activity in vitro against various pathogens. Auxiliary mechanism beyond the central GABAergic and HPA-axis effects.

Clinical trials

1
Relora® Anxiety + Sleep Clinical Trial

Randomized parallel placebo-controlled 6-week trial in healthy overweight premenopausal women using Relora® 250 mg capsules three times daily.

Premenopausal women

Randomized parallel placebo-controlled 6-week trial in healthy overweight premenopausal women using Relora® 250 mg capsules three times daily. Anxiety reduction via Spielberger State-Trait inventory plus salivary amylase and cortisol; sleep quality and latency improved per Likert/VAS. Combination product (Magnolia officinalis + Phellodendron amurense) — not purified honokiol.

2
Alexeev — Magnolol + Honokiol GABA-A Mechanism Characterization

Clinical evidence on Honokiol (Magnolia officinalis Bark) for the indications and outcomes described.

Clinical population described in trial publication.

Alexeev et al. (Neuropharmacology) — characterized magnolol and honokiol as positive allosteric modulators of both synaptic and extra-synaptic GABA-A receptors. Mechanism distinct from the benzodiazepine binding site; subunit heterogeneity sensitivity. Foundational pharmacology paper supporting the anxiolytic and sleep clinical findings.

3
+ — Magnolia Anxiety/Sleep Aggregate

Two clinical studies (and) finding magnolia extracts reduce temporary anxiety and improve sleep.

Clinical population described in trial publication.

Two clinical studies (and) finding magnolia extracts reduce temporary anxiety and improve sleep. Aggregate small-trial clinical signal supporting the mild anxiety/sleep adjunct positioning.

Side effects and drug interactions

Common Potential side effects

Generally well-tolerated at typical doses.
GI upset (rare).
Heartburn, trembling hands, sexual dysfunction, thyroid dysfunction reported in 4 patients across Relora studies (n=58 postmenopausal women, 6 weeks) — causality unclear (honokiol vs berberine vs combination).
Toxicology concern: methanol extract of M. officinalis (2 mg/day honokiol equivalent for 3 months in mice) showed changes IN kidney function clinical parameters + kidney ULTRASTRUCTURE alterations. Clinical translation uncertain. Other animal toxicology studies have not reported significant safety concerns.
Pregnancy/lactation: avoid (limited safety data).
Very high doses: theoretical hepatotoxicity, GI disturbances, neurotoxicity per limited evidence.
NO ongoing clinicaltrials.gov registered honokiol trials in the US — limited modern clinical safety data.
Long-term safety: limited human data beyond 6-week trials.

Important Drug interactions

Benzodiazepines: theoretical synergistic effects (both GABA-A modulators, different sites) — caution.
Alcohol: theoretical additive sedation — avoid combination.
Anticoagulants: theoretical mild antiplatelet effect.
Antihypertensives: theoretical mild effects.
Most medications: caution due to limited modern PK/interaction data.
Other CNS depressants: theoretical additive sedation.

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Frequently asked questions about Honokiol (Magnolia officinalis Bark)

What is honokiol used for?

Honokiol is a key active compound from magnolia bark, used for relaxation, stress and sleep support, and studied for antioxidant, brain, and cellular-health effects. It promotes calm partly by supporting GABA activity.

What is honokiol good for?

It is used for easing stress and supporting sleep and a calm mind (it is the more calming of magnolia's compounds), and is studied for neuroprotective and antioxidant support. It is often delivered via magnolia bark extracts.

How much honokiol should I take?

It is dosed via standardized magnolia bark extracts; follow product labeling. For stress and sleep, it is often taken in the evening.

Is honokiol safe?

It is generally well tolerated. Because it is calming, it may add to sedatives and alcohol, so use caution combining them. Pregnant women should avoid it, and those on medication should check with a doctor.

What is Honokiol?

Honokiol is a bi-phenolic natural compound from the bark and seed cones of Magnolia officinalis — used in Traditional Chinese Medicine for over two millennia under the name 'hou po' to regulate Qi. It's a positional isomer of magnolol, with both compounds typically present together in magnolia bark extracts.

What is the recommended dosage of Honokiol?

The clinically studied dose is Purified honokiol 250 mg 1-2x daily; Relora (magnolia + phellodendron) 250-300 mg 2-3x daily. Always follow the product label and check with a healthcare provider for personal advice.

Is Honokiol safe, and does it have side effects?

For most healthy adults, Honokiol is well tolerated at studied doses. Reported effects can include: Generally well-tolerated at typical doses. GI upset (rare). It may also interact with some medications. Honokiol is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Honokiol interact with any medications?

Possible interactions include: Benzodiazepines: theoretical synergistic effects (both GABA-A modulators, different sites) — caution. Alcohol: theoretical additive sedation — avoid combination. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Honokiol?

NutraSmarts rates the evidence for Honokiol as Limited (2 out of 5). It is backed by 3 clinical trials and 3 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(3 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Talbott SM, Talbott JA, Pugh M Effect of Magnolia officinalis and Phellodendron amurense (Relora®) on cortisol and psychological mood state in moderately stressed subjects Journal of the International Society of Sports Nutrition. 2013;10(1):37. doi:10.1186/1550-2783-10-37.PubMedUsed to support: 4-week double-blind RCT of Relora® (standardized Magnolia officinalis + Phellodendron amurense extract containing honokiol/magnolol) in moderately stressed adults: salivary cortisol exposure significantly lower (−18%, p<0.05) vs placebo; stress −11%, depression −20%, anger −42%, global mood +11%. Note: this paper studies the Relora® blend containing honokiol as the primary active, not isolated honokiol.
  2. Kalman DS, Feldman S, Feldman R, Schwartz HI, Krieger DR, Garrison R Effect of a proprietary Magnolia and Phellodendron extract on stress levels in healthy women: a pilot, double-blind, placebo-controlled clinical trial Nutrition Journal. 2008;7:11. doi:10.1186/1475-2891-7-11.PubMedUsed to support: Pilot double-blind RCT of Relora® (Magnolia officinalis + Phellodendron amurense blend, primary active honokiol/magnolol) in healthy women: significantly reduced transitory/state anxiety (Spielberger state, p<0.05) vs placebo. Note: this paper studies the Relora® blend containing honokiol, not isolated honokiol; honokiol is the key active constituent of Magnolia officinalis bark.
  3. Qu WM, Yue XF, Sun Y, Fan K, Chen CR, Hou YP, Urade Y, Huang ZL Honokiol promotes non-rapid eye movement sleep via the benzodiazepine site of the GABA(A) receptor in mice British Journal of Pharmacology. 2012;167(3):587-598. doi:10.1111/j.1476-5381.2012.02010.x.PubMedUsed to support: In vivo (mouse) and in vitro electrophysiology study: honokiol promoted NREM sleep by modulating the benzodiazepine-binding site on GABA(A) receptors; flumazenil blocked the effect. Supports GABA-A receptor modulation mechanism underlying anxiety and sleep benefits. Note: animal/in vitro mechanism study, included as genuine mechanistic basis.