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16 Health Benefits of Magnolia Bark + Dosage, Side Effects

Written by Will Hunter, BA (Psychology) | Last updated:
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology) | Written by Will Hunter, BA (Psychology) | Last updated:

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Magnolia bark is a staple of traditional Chinese medicine and is used today for a variety of health benefits ranging from the treatment of depression and insomnia to enhancing cancer drug therapy. The bark possesses anti-inflammatory, calming, and antioxidant effects. Read on to find out the benefits, dosage, and side effects of taking magnolia bark.

What is Magnolia Tree/Bark?

The magnolia tree (Magnolia officinalis), known as Houpu in Chinese medicine, is found in Southeast Asia. It was traditionally used to treat gastrointestinal (GI) disorders, anxiety, depression, nervous disorders, asthma, and allergic diseases.

The magnolia tree has a fragrant aroma and bright flowers. During the summer, the root and bark from the trees are harvested, dried, slightly boiled, and let to turn a purple-brown color. After being softened by steaming and rolling, this bitter and fragrant extract is used in medicine and dietary supplements for its various health benefits [1].

Magnolia bark extract is often used in combination with Phellodendron bark extract in a supplement called Relora that is used for anxiety [2, 1].


Magnolol and honokiol are lignans that are the major active components of magnolia bark extract. Various alkaloids (aporphine and benzylisoquinoline derivatives) and volatile oils (consisting of sesquiterpenoid alcohols, α-, β-, and γ-eudesmol) make up the rest of the extract [1].

Mechanism of Action

Honokiol maintains sodium-potassium channel activity that is vital for communications between neurons [3].

Honokiol prevents glucose intolerance, which otherwise would severely damage neuron cells because they require a high amount of energy to function [4].

Honokiol prevents the formation of necrotic tissue in rat brains by stopping neutrophil (immune cells that kill damaged cells and harmful pathogens) activity and neutralizing reactive oxygen species such as hydrogen peroxide [4].

Honokiol prevents neurotoxicity by inhibiting the production of nitric oxide by an enzyme called nNOS. This enzyme depends on calcium, which is allowed into cells by a glutamate (a neurotransmitter) receptor called the NMDA receptor. However, if too much calcium is taken in by the cells, this leads to the production of pro-oxidants like superoxide and peroxynitrite and ends in cell death [5, 6, 7, 8, 4, 9].

Honokiol and magnolol block glutamate receptors in mice, preventing glutamate from binding to them. This prevents the glutamate-activated NMDA receptor from being activated too much, preventing seizures and premature cell death. Overstimulation of NMDA receptors is associated with many neurological disorders including epilepsy, stroke, mood disorders, and Alzheimer’s [10, 11, 4].

By stimulating the GABA-A receptor, honokiol produces a relaxing and calming effect. Honokiol also binds to the benzodiazepine site of the GABA-A receptor of neurons, impacting sleep cycles and helping with insomnia [12, 4, 13].

Honokiol also activates genes controlled by the molecule Nrf2, which protects against oxidative stress [14].

Health Benefits

1) May Help with Depression

Honokiol and magnolol produced antidepressant effects in and improved the energy levels of mice by increasing their serotonin and noradrenaline levels in the prefrontal cortex [15].

Serotonin is a neurotransmitter that allows for rapid signaling between neurons in the brain. Psychological disorders such as depression, mania, and anxiety are often linked to low levels of serotonin [16, 17]

Noradrenaline (norepinephrine) is a neurotransmitter that is heavily involved with the onset of depression. Low levels of noradrenaline can cause decreased energy, inability to concentrate, decreased alertness, and decreased cognitive abilities. Noradrenaline is also involved in regulating emotions [18].

2) May Help with Anxiety

Honokiol has been shown in animal studies to reduce anxiety with fewer side effects than diazepam, a drug commonly prescribed for anxiety disorders. Honokiol increases GABA levels, which helps decrease anxiety [4, 13].

3) May Help Prevent Cavities

A cell study showed that magnolol and honokiol, key components of magnolia bark, have significant antimicrobial activity against the bacteria Streptococcus mutans. S. mutans can be harmful to oral health, as it creates an acidic environment that makes plaque buildup possible, which destroys enamel and leads to the formation of cavities [19, 20].

4) May Reduce Inflammation

Cytokines are the signaling molecules of the immune system that impact the severity of inflammation, which contributes to swelling, pain, and other typical side effects of inflammation.

In a study involving magnolia bark extract administered to cells involved with the initial immune response (activated fibroblasts and monocytes), the extract effectively lowered the number of proinflammatory cytokines IL-6, IL-8, MMP-2, and MMP-9 [21].

5) May Protect Against Brain Damage from Seizures

Honokiol helped prevent and reduce the severity of seizures and reduced impairments in the movement of mice by blocking NMDA receptors [22].

6) May Prevent Memory Loss and Learning Impairments

Scopolamine is an anti-nausea drug that causes memory and learning impairments. Honokiol improved spatial learning and memory function in mice given scopolamine and reduced levels of the proinflammatory cytokines IL-1β while increasing levels of the anti-inflammatory cytokine IL-10 [23].

An alcohol extract of magnolia bark helped prevent memory loss caused by bacterial lipopolysaccharides in mice. Lipopolysaccharides are a toxin found in Gram-negative bacteria that activates the cells that protect the brain from attack from pathogens (microglia) by triggering the release of cytokines.

Chronically-activated microglia cause oxidative stress, leading to neuron damage and death. Eventually, these effects may contribute to the onset of neurodegenerative diseases like Alzheimer’s disease [24, 25].

7) May Help Reduce Pain Caused by Inflammation

Honokiol and magnolol reduced pain caused by drug-induced inflammation in mice but did not reduce pain caused by heat or force [26].

Glutamate and glutamate receptors, as well as the inflammatory molecules substance P and prostaglandin E2, are known to increase the sensitivity to pain. One study found that honokiol and magnolol prevented inflammatory pain in mice injected with glutamate [11].

8) May Help Prevent and Fight Cancer

Honokiol inhibits the activity of the proteins Nf-kB and STAT3 (transcription factors), which prevent cancer cell communication and tumor spread and growth. Also, by preventing the activation of STAT3, honokiol decreases the activation of the signaling molecules c-Src and EFGR, which are often abundant in cancer cells [27].

Honokiol applied to the skin of mice resulted in an 80% decrease in benign tumor size and a 62% decrease in the progression of benign tumors to malignant tumors [27].

Mice with lung cancer that were treated with honokiol and radiation saw a 78% reduction in tumor volume. This combination was more effective than either honokiol or radiation alone [28].

Honokiol prevented the growth of various types of breast cancer cells and also made drug treatment more effective by blocking the production of P-glycoprotein, a protein that pumps foreign substances out of cells, which reduces the effectiveness of chemotherapy [27].

Mice containing human ovarian cancer cells that were treated twice weekly with honokiol saw an 88% inhibition in tumor growth and an increased lifespan [29].

Honokiol containing human prostate cancer cells administered orally to mice increased the amount of cell death (apoptosis) at tumor sites and slowed the growth of cancer [30].

A cell study involving human colorectal cancer cells found that honokiol led to increased cell death at tumor sites and prevented tumor growth [31].

Honokiol caused cell death in human gastric cancer cells in a cell study and in mice with gastric cancer. It also decreased the production of key molecules involved in tumor growth (Peroxisome proliferator-activated receptor-gamma (PPAR-gamma), COX-2 and 15-lipoxygenase (LOX)-1) [32].

A cell study on human pancreatic cancer cells found that honokiol caused cancer cell death and increased the effectiveness of the chemotherapeutic drug gemcitabine [33].

9) Helps with Symptoms of Menopause

In a study of 934 women experiencing menopause, tablets containing a combination of magnolia extract and a soy-based supplement were given once a night for 12 weeks. The women experienced improvements in insomnia, anxiety, depression, and libido [34].

10) May Help with Insomnia

Honokiol promoted NREM, or dreamless sleep, in mice. Magnolol increased both NREM and REM sleep episodes by increasing the amount of GABA released from neurons in the brain. Magnolia extract overall was found to exhibit a relaxing effect [35].

In a study of 89 menopausal women, magnolia extract combined with a magnesium supplement helped alleviate sleep disturbances [36].

11) May Help with Weight Loss

Magnolia bark extract decreased body fat mass in mice. Honokiol significantly lowered triglyceride and cholesterol levels and decreased insulin resistance, preventing fat storage [37].

12) May Help Lower High Blood Pressure

Honokiol significantly relaxed aortas and reduced blood pressure in rats with high blood pressure [38].

13) May Help with Asthma

A cell study done on immune cell production showed that magnolia extract can block the type 4 allergic reaction (delayed response type caused by the overactivity of T lymphocytes, which are involved in the adaptive immune system). Magnolol and honokiol provide a relaxing effect that dilates bronchial vessels in the lungs, allowing for easier breathing, as seen in a study involving pig trachea contraction and relaxation [1].

In a study of 148 mild and moderate asthma patients taking corticosteroids for their condition, the magnolia extract was effective in improving asthma control and preventing extreme attacks [39].

14) May Help with Symptoms of Enlarged Prostate

In a cell study, prostate gland tissue treated with honokiol reduced smooth muscle contraction and prevented excessive cell growth, indicating magnolia extract may help with symptoms of enlarged prostate in men [40].

15) May Treat Diabetes

Magnolol and honokiol reduced fasting blood sugar levels, increased sugar tolerance of cells, and increased insulin levels all without causing weight gain in type 2 diabetic rats [1].

16) May Help Delay Progression of Alzheimer’s Disease

Magnolol and honokiol decreased neuron death by protecting them from high calcium levels and inhibiting caspase, an enzyme that breaks down muscle-specific proteins and causes cell death.

Magnolol and honokiol limited the activity of the B-secretase enzyme, which is overactive in Alzheimer’s disease patients and leads to the formation of amyloid plaque buildup [41, 1].

Limitations & Caveats

While the research strongly supports the use of magnolia bark in benefiting multiple conditions and diseases, most of it has been conducted in rodents. Therefore, caution is warranted when applying this information for use in humans.

Side Effects & Precautions

Side Effects

At high doses (greater than 9 g), excessive bleeding or neurotoxicity can occur [4, 42].

Those with a bleeding disorder or clotting disorder are not recommended to take magnolia supplements. This includes those who have hemorrhages or patients with disorders such as hemophilia or von Willebrand’s deficiency [4].

Multiple animal studies reported no change in diet, appetite, weight, or other body activities. No mutations were observed and toxicity tests done over 90 days reported no mortalities [27].


Menopausal women taking magnolia supplements to help with insomnia, anxiety, and depression may experience constipation, breast tension, blood loss, and stomach pain [34].

Drug Interactions

Patients taking anticoagulants such as Coumadin or Lovenox should not take magnolia bark extract as it reduces blood clotting [4].



Dietary supplements often contain magnolia bark extract in doses between 200 mg to 800 mg taken daily [1].

User Experiences

One user noted that they fell asleep much quicker and had better sleep.

Another user experienced better sleep and lowered anxiety levels. However, they noted that the effect diminished after a couple of days.

Some users report headaches and drowsiness.


Want Better Ways to Improve Your Mood?

If you’re interested in natural and targeted ways of improving your mood, we recommend checking out SelfDecode’s Mood DNA Wellness Report. It gives genetic-based diet, lifestyle and supplement tips that can help improve your mood. The recommendations are personalized based on your genes.

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About the Author

Will Hunter

BA (Psychology)
Will received his BA in Psychology from the University of California, Los Angeles. 
Will's main passion is learning how to optimize physical and mental performance through diet, supplement, and lifestyle interventions. He focuses on systems thinking to leverage technology and information and help you get the most out of your body and brain.

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