Psilocybin, the psychedelic compound found in certain mushrooms, may help protect peripheral nerves from chemotherapy-related damage, according to promising new laboratory research.
The study, published in Science, found that administering psilocybin before chemotherapy prevented several signs of chemotherapy-induced peripheral neuropathy in mice. Treated animals retained touch sensation, experienced less abnormal sensitivity to cold and pressure, and showed reduced damage to sensory nerve endings.
Researchers also reported that psilocybin did not weaken chemotherapy’s antitumour activity in the experimental models. However, the findings remain preclinical. The compound has not yet been proven safe or effective for preventing nerve damage in cancer patients.
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Why Chemotherapy-Related Nerve Damage is a Major Concern
Chemotherapy-induced peripheral neuropathy, or CIPN, occurs when cancer medicines damage nerves outside the brain and spinal cord. It is particularly associated with platinum-based drugs such as cisplatin and oxaliplatin and taxanes, including paclitaxel and docetaxel.
Symptoms generally begin in the fingers and toes and may spread into the hands, feet, arms or legs. Patients can experience burning pain, tingling, numbness, cold sensitivity, muscle weakness and difficulty maintaining balance. Reduced sensation may also prevent people from noticing injuries or temperature changes.
The US National Cancer Institute’s information on peripheral neuropathy explains that nerve damage can interfere with walking, holding objects and completing routine activities.
A systematic review involving 4,179 patients estimated that neuropathy affected approximately 68% of patients during the first month after chemotherapy. Around 30% continued to experience symptoms six months or longer after treatment.
Severe neuropathy can also disrupt cancer care. Doctors may need to reduce a chemotherapy dose, postpone a treatment cycle or discontinue the medicine responsible for the damage.
How Psilocybin Protected Sensory Nerves in Mice
Researchers tested psilocybin in mouse models treated with cisplatin, paclitaxel, and docetaxel. In one experiment, mice received two psilocybin doses before their first cisplatin treatment, one nine days before chemotherapy and another two days beforehand.
The animals receiving psilocybin developed significantly fewer neuropathy-related symptoms than untreated mice. Protection continued during repeated chemotherapy exposure, including experiments covering as many as six treatment cycles.
Importantly, the findings indicated more than temporary pain relief. Researchers examined nerve endings in the animals’ skin and found that psilocybin helped preserve their physical structure. The treated mice also maintained sensory functions that chemotherapy would ordinarily impair.
This distinction matters because conventional pain medicines may reduce discomfort without preventing the underlying nerve injury. Psilocybin appeared to act as a neuroprotective treatment, helping stop damage before it became established.
How Psilocybin May Keep Nerve Cells Functioning
The proposed biological mechanism involves mitochondria, the structures that supply cells with usable energy.
Peripheral nerve fibres can extend over considerable distances. Mitochondria must therefore travel through these fibres to deliver energy to nerve endings in the hands, feet and other distant areas. Chemotherapy can disrupt this internal transport system, leaving nerve endings without sufficient energy.
In the experiments, cisplatin reduced mitochondrial motility and depleted adenosine triphosphate (ATP) levels within nerve projections. ATP is the primary molecule cells use to store and transfer energy.
Psilocybin preserved mitochondrial movement, allowing energy supplies to continue reaching vulnerable parts of the nerve. This may explain why sensory nerve endings remained functional despite exposure to chemotherapy.
Researchers connected the effect to the serotonin 5-HT2A receptor, which is also involved in psilocybin’s psychedelic effects. Blocking the receptor removed the compound’s nerve protection.
A non-hallucinogenic experimental compound targeting the same receptor produced similar benefits in mice. The result raises the possibility of developing future medicines that protect nerves without causing an intense psychedelic experience.
Current Treatments Cannot Reliably Prevent Neuropathy
Doctors currently have limited options for preventing chemotherapy-induced peripheral neuropathy. Management generally involves monitoring symptoms, modifying chemotherapy when necessary and helping patients cope with pain or functional problems.
The American Society of Clinical Oncology guideline does not recommend any medicine for the routine prevention of CIPN. Duloxetine may provide limited relief for some patients with established painful neuropathy, but it does not repair damaged nerves.
A preventive treatment would therefore represent an important advance. Protecting nerve endings before chemotherapy to prevent lasting injury could help patients preserve mobility, independence, and quality of life while completing their planned cancer treatment.
Human Trial Will Test Whether the Findings Translate
NeuroGuard, a Phase 2 human study, will investigate the laboratory findings.
According to the NeuroGuard clinical trial record, researchers plan to examine psilocybin in adults receiving neurotoxic chemotherapy for breast, colorectal, and head and neck cancers.
The study will compare a therapeutic psilocybin dose with control approaches, including standard supportive care and a low subperceptual dose. Researchers will evaluate sensory symptoms, pain, physical functioning, safety, quality of life and whether patients can receive chemotherapy as scheduled.
A successful Phase 2 trial would provide important evidence, but larger studies would still be required to establish appropriate dosing, long-term safety and which patients could receive the treatment.
Psilocybin is Not an Approved Treatment
Patients should not use psychedelic mushrooms or unregulated psilocybin products before or during chemotherapy, based on this study.
Psilocybin can cause hallucinations, anxiety, panic, nausea, confusion, impaired judgement and temporary increases in blood pressure or heart rate. It may also be unsuitable for people with certain psychiatric or cardiovascular conditions or those taking medicines that affect serotonin.
Research-grade psilocybin administered under medical supervision is fundamentally different from consuming mushrooms with uncertain potency or composition.
For now, the study provides an encouraging scientific lead rather than an available therapy. Its broader value may ultimately lie in identifying a biological pathway that researchers can target with psilocybin or future non-hallucinogenic medicines. Whether that approach can safely protect cancer patients will depend on the results of controlled human trials.
