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Honokiol Protects Hearing From Chemotherapy Drug Cisplatin In Mice

A compound from magnolia bark preserved hearing in tumor-bearing mice given chemotherapy, pointing to a possible way to protect hearing during cancer treatment.

By Dr. Axe Editorial Team · October 18, 2026 · 1 source · Watch

Honokiol, a compound derived from magnolia bark, protected the inner ear from cisplatin chemotherapy damage in a mouse study published in October 2026 in Pharmaceuticals, with 10 mg/kg emerging as the optimal dose for preserving hearing and survival.

10mg/kg optimal dose

5sirtuins activated

Researchers tested honokiol, a compound from magnolia bark, in adult female mice carrying a tumor-causing oncogene that produced spontaneous tumors around 70.8 days of age on average. The mice received three two-week cycles of low-dose cisplatin chemotherapy (4 mg/kg per day for four days each cycle, given by injection), a regimen designed to mimic human chemotherapy protocols. Honokiol, at doses ranging from 5 to 20 mg/kg, was given one hour before each cisplatin dose. Cisplatin caused hearing loss concentrated in the high-frequency range of 24 to 32 kHz, measured by auditory brainstem response thresholds (a hearing test that measures the ear's electrical response to sound). Honokiol reduced this damage, and 10 mg/kg best balanced hearing protection with animal survival. Fluorescence staining showed increased signal for five sirtuin proteins (sirtuins 1, 2, 3, 5 and 7) in the cochlea of honokiol-treated mice, and a gene-expression test confirmed a measurable increase specifically in sirtuin 3 messenger RNA.

Sirtuins are enzymes inside cells that help manage oxidative stress, a type of cellular damage linked to chemotherapy's toxic effects on the ear. The study authors report that honokiol's hearing protection coincided with increased activity across the sirtuin family, with sirtuin 3 showing confirmed genetic upregulation, suggesting these enzymes play a role in shielding the inner ear's sound-sensing cells from cisplatin's damage.

Optimal Honokiol Dose

Pharmaceuticals, 2026, Thomas et al.

This is one tumor-bearing mouse model, and findings in mice do not establish what happens in people on chemotherapy. The abstract does not give hearing-threshold numbers by dose group or describe adverse effects from honokiol itself, and human studies have not been done.

Dr. Axe’s Take

My view: Cisplatin-induced hearing loss is one of the most frustrating side effects of chemotherapy, and this mouse study offers a real mechanistic lead: honokiol switching on sirtuins, the cell's defense against oxidative stress, right where chemotherapy damages hearing. Magnolia bark extract containing honokiol has a long history in traditional Chinese medicine, but this is animal data at specific lab doses, not a green light for self-treating during chemo. Anyone on cisplatin should keep taking their prescribed regimen and talk with their oncologist before adding honokiol, given how early this research is.

— Dr. Axe

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Study summary

Who: Tumor-bearing adult female mice, developing tumors at an average age of about 71 days
Design: Animal study, three two-week chemotherapy cycles with honokiol pretreatment versus cisplatin alone
Dose: Cisplatin 4 mg/kg/day for 4 days per cycle; honokiol 5-20 mg/kg, with 10 mg/kg optimal
Primary result: Honokiol reduced high-frequency (24-32 kHz) hearing loss from cisplatin and improved survival at 10 mg/kg
Secondary: Sirtuins 1, 2, 3, 5 and 7 showed increased fluorescence signal in the cochlea; sirtuin 3 mRNA was significantly upregulated by RT-qPCR
Funding / conflicts: Funders listed in the journal record: Hearing Health Foundation; American Hearing Research Foundation; Department of Otolaryngology, Feinberg School of Medicine at Northwestern University; National Institutes of Health. Conflicts not reported in the abstract.
Date: Oct 12, 2026