Honokiol: Benefits, Key Mechanisms, and the Side Effects of Potent Magnolia Bark Extract

Sept 21, 2023 | Written by Scott Sherr, MD and Marion Hall | Reviewed by Marion Hall

person by a magnolia tree

Honokiol is a natural compound derived from the bark and seed cones of the Magnolia tree. It has a long history of use in traditional medicine, particularly in East Asia. It has gained significant attention in recent years due to its potential therapeutic properties, especially as an allosteric modulator of GABA receptors (i.e., a compound that increases GABA in the brain). 

Honokiol's History

The synthesis of honokiol began in the 1990s when researchers started exploring its chemical structure and properties. Through various extraction and purification techniques, scientists were able to isolate and synthesize honokiol in a laboratory setting. This breakthrough allowed for further investigation into its potential applications.

How Honokiol Works

One of the key mechanisms of honokiol is its interaction with GABA receptors in the brain. GABA receptors are responsible for regulating the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), which plays a crucial role in reducing neuronal excitability.

It is believed that honokiol acts as a positive allosteric modulator of GABA receptors, meaning that it enhances the receptor's response to GABA. This interaction can lead to increased GABAergic neurotransmission, promoting relaxation and reducing anxiety.

Furthermore, honokiol has been found to increase the activity of the enzyme glutamic acid decarboxylase (GAD), which is responsible for synthesizing GABA. By increasing GAD activity, honokiol can potentially boost GABA production, further enhancing its calming effects.

Several studies have investigated the interaction between honokiol and GABA receptors. One study published in Neuropharmacology found that honokiol increased GABAergic neurotransmission in the hippocampus, a brain region involved in memory and emotions. Another study published in Psychopharmacology demonstrated that honokiol exerted anxiolytic effects through its interaction with GABA receptors.

In addition to its effects on GABA receptors, honokiol also interacts with other receptors in the brain, such as those of serotonin and dopamine. These interactions contribute to its anxiolytic, antidepressant, and neuroprotective properties.

The more active form of honokiol, dihydrohonokiol-beta (DHHB), has similar effects to honokiol but has a greater affinity for the allosteric site on the GABA receptor.

Health Benefits of Honokiol

Several clinical studies have investigated the potential therapeutic benefits of honokiol and its antidepressant-like effects in both humans and animals. These studies have shown promising results in various areas. 

Anxiety and Stress Reduction of Honokiol

A study published in the Journal of Ethnopharmacology found that honokiol exhibited anxiolytic effects in mice, reducing anxiety-like behaviors. Another clinical trial conducted on humans showed that honokiol supplementation reduced anxiety symptoms and improved overall well-being.

Anticancer Properties of Honokiol

Research on honokiol suggests that magnolia bark possesses potent anticancer properties. A study found that honokiol may inhibit the growth of various cancer cells, including breast, lung, prostate, and colon cancer. Honokiol's ability to induce apoptosis (programmed cell death) and inhibit angiogenesis (formation of new blood vessels) makes it a promising candidate for cancer treatment.

Neuroprotective Effects of Magnolia Bark

Studies suggest that honokiol and magnolol, the latter another compound found in the bark of Magnolia officinalis, have neuroprotective effects, making them potentially beneficial for neurodegenerative disorders such as Alzheimer's and Parkinson's disease. The administration of honokiol has been found to protect neurons from oxidative stress, reduce inflammation, and enhance cognitive function.

Honokiol Safety and the Side Effects of Magnolia Bark

Despite the many health benefits of magnolia bark, several studies have also highlighted its potential drawbacks. These studies suggest that at very high doses, honokiol may have potential neurotoxicity, raising concerns about its impact on the nervous system. Beyond that, at elevated concentrations, honokiol may lead to gastrointestinal disturbances and hepatotoxicity, potentially causing liver damage.

These findings emphasize the importance of carefully considering dosages and monitoring honokiol's use in clinical applications to mitigate potential adverse reactions. As with any medicinal compound, make sure to do your research and ask your doctor before use to avoid negative reactions to any medications you may currently be taking!


What is honokiol?

Honokiol is a natural compound extracted from the bark and seed cones of the Magnolia tree, specifically Magnolia officinalis. It's been used in traditional Chinese medicine for centuries and has gained attention due to its potential health benefits.

What is honokiol good for?

Honokiol and its counterpart magnolol have several potential benefits. They are believed to interact with GABA receptors in the brain, promoting relaxation and reducing anxiety. The use of magnolia bark, including honokiol, also extends to its possible neuroprotective properties.

Is honokiol safe to take?

As a dietary supplement, honokiol is generally considered safe to take. However, like any supplement, it may have side effects. Always consult your healthcare provider before starting any new supplement regimen.

Does honokiol help with sleep?

Yes, one of the effects of honokiol is promoting relaxation, which can aid in improving sleep quality. Its potential sedative properties are often attributed to its interaction with GABA receptors.

Is honokiol a sedative?

While honokiol isn't classified as a sedative, one of the benefits of magnolia bark extract, which includes honokiol, is its calming effect. This effect of magnolol and honokiol is often associated with better sleep and reduced anxiety.


Honokiol shows great potential as a natural compound with various therapeutic benefits, especially as a positive allosteric modulator of the GABA receptor. When there is more GABA, the brain is more relaxed, less stressed, calms (and sleeps) easier, and much more. 

Have you tried honokiol? Would you like to? Then check out Tro Zzz, our buccal troche formulated for sleep, which has honokiol as one of its main ingredients!



  1.  Liou KT, Lin SM, Huang SS, Chih CL, Tsai SK. Honokiol ameliorates cerebral infarction from ischemia-reperfusion injury in rats. Planta Med. 2003;69(2):130-134. doi: 10.1055/s-2003-37707
  2. Sarrica A, Kirika N, Romeo M, Salmona M, Diomede L. Safety and Toxicology of Magnolol and Honokiol. Planta Med. 2018;84(16):1151-1164. doi: 10.1055/a-0642-1966
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  4. Woodbury A, Yu SP, Wei L, García P. Neuro-modulating effects of honokiol: a review. Front Neurol. 2013;4:130. Published 2013 Sep 11. doi: 10.3389/fneur.2013.00130
  5. Xu Y et al. Honokiol improves cognitive impairment by inhibiting ferroptosis and activating the Nrf2/ARE signaling pathway in a mouse model of Alzheimer's disease. Journal of Molecular Neuroscience 2019;68(2):263-275.
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