Ginkgo Biloba for Post-COVID Brain Fog and Tinnitus

Cognitive impairment is a frequent and debilitating feature of post-COVID-19 syndrome (PCS), with no established treatments targeting its underlying causes. A new clinical trial, the EGb COCOS study, will test whether a specific Ginkgo (Ginkgo biloba extract) biloba extract can address the neurobiological mechanisms driving this cognitive dysfunction.

The Challenge of Post-COVID Cognitive Impairment

For many individuals with PCS, often called long COVID, cognitive problems like brain fog, memory lapses, and poor concentration are among the most disruptive symptoms. Research by Jordi A. Matias-Guiu, Katrin Arélin, Paula Jiménez Serrano, and others points to specific pathological changes in the brain. These include chronic neuroinflammation, dysfunction in the brain’s microcirculation, and impaired energy production in neurons. Since no therapies directly modify these processes, current management is limited to symptom relief. This leaves a significant gap in patient care.

EGb 761®: A Multi-Target Botanical Extract

The investigational treatment, EGb 761®, is not a generic ginkgo supplement. It is a specific, standardized dry extract from Ginkgo biloba leaves with a defined pharmacological profile. Preclinical and clinical studies show it has three key properties relevant to PCS pathology: it reduces neuroinflammation, improves cerebral microcirculation, and supports mitochondrial function in neurons. The authors note that clinical efficacy for cognitive impairment in other conditions, like age-related cognitive decline, has been demonstrated. Because its known actions align with the suspected causes of post-COVID cognitive issues, the researchers propose it as a rational candidate for treatment.

Initial case series have reported significant cognitive improvement in PCS patients after six months of EGb 761® treatment. These observations provided the impetus for designing a rigorous, controlled trial.

Design of the EGb COCOS Clinical Trial

The EGb COCOS study is a prospective, multicenter, randomized, placebo-controlled, and triple-blind trial. It plans to enroll 400 participants aged 18 or older who have a history of SARS-CoV-2 infection and a diagnosis of PCS. Eligible patients must have cognitive symptoms persisting for at least two months, objective evidence of cognitive impairment, and mild-to-moderate anxiety or depressive symptoms.

Participants will be randomly assigned to receive either 240 mg of EGb 761® or a matching placebo, taken once daily for 12 weeks. The triple-blind design ensures that the participants, the care providers, and the researchers assessing outcomes will not know who is receiving the active treatment.

Measuring a Range of Patient-Centered Outcomes

The study will assess the extract’s impact on four key areas: cognitive performance, neuropsychiatric symptoms (anxiety and depression), neurosensory symptoms, and overall functional outcomes. The inclusion of neurosensory outcomes is particularly relevant for a hearing health audience, as it means the trial will track symptoms like tinnitus and hyperacusis, which are common in PCS. This broad assessment approach recognizes that PCS affects multiple, interconnected brain networks.

The researchers state the analysis will be exploratory, as there are no universally validated primary endpoints for PCS cognitive trials yet. Safety will be monitored by recording all adverse events and serious adverse events.

Implications for Hearing and Sound Sensitivity Disorders

The potential connection between this trial and hearing health is direct. Tinnitus and hyperacusis are neurosensory symptoms frequently reported in PCS and are believed to share underlying mechanisms with cognitive dysfunction, such as central nervous system hyperactivity and neuroinflammation. If EGb 761® demonstrates efficacy in calming neuroinflammation and improving cerebral circulation, benefits may extend beyond memory and focus to these auditory symptoms.

This aligns with a growing research focus on the brain’s role in hearing disorders. For instance, investigations into glymphatic system function using DTI-ALPS analysis explore how waste clearance in the brain relates to conditions like tinnitus. A treatment that improves overall brain health and vascular function could positively influence these systems. Furthermore, the trial’s measurement of anxiety and depression is critical, given the strong comorbidity between tinnitus, hyperacusis, and mental health conditions.

A Practical, Patient-Focused Approach

For individuals struggling with the cognitive and sensory after-effects of COVID-19, this trial represents a concrete step toward a potential treatment. The 12-week duration and focus on measurable, daily-life outcomes are designed to provide clear, practical evidence. It also highlights the importance of integrated care; cognitive impairment rarely exists in isolation and is often accompanied by mood changes and sensory disturbances like tinnitus.

The intersection of cognitive and auditory symptoms in PCS also underscores the importance of holistic management. While awaiting disease-modifying treatments, managing contributing factors remains essential. For example, cognitive behavioral therapy for insomnia (CBT-I) has shown that addressing sleep and mood can improve long-term outcomes, and principles of good sleep hygiene are a foundational part of managing any chronic neurological condition.

Awaiting the Evidence

The EGb COCOS trial, registered as CTIS2024-517199-39-00, is now underway. Its results, expected in the coming years, will provide the first high-quality evidence on whether EGb 761® is an effective intervention for cognitive impairment in PCS. If positive, it would offer a treatment option that targets the proposed biological roots of the problem, not just its symptoms. For the hearing health community, it may also offer valuable insights into managing the tinnitus and hyperacusis that so often travel alongside cognitive dysfunction in post-COVID syndrome.

Source: Matias-Guiu, J. A., Arélin, K., & Jiménez Serrano, P. (2026). EGb 761 ® for cognitive impairment in post-COVID-19 syndrome: study protocol of the EGb COCOS trial. Frontiers in Human Neuroscience.