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Study on the Effects and Safety of Ginkgo Biloba Extract in Patients with Cognitive Impairment After COVID-19

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the effects and safety of a treatment for people experiencing cognitive impairment related to post-COVID-19 syndrome. Cognitive impairment refers to difficulties with memory, attention, and thinking skills. Post-COVID-19 syndrome, also known as long COVID, includes symptoms that persist for weeks or months after the initial COVID-19 infection. The treatment being tested is a specific extract from the leaves of the Ginkgo biloba tree, known as EGb 761®. This extract is taken in the form of a 240 mg film-coated tablet.

The purpose of the study is to evaluate how well EGb 761® works compared to a placebo in improving cognitive function in individuals with cognitive impairment due to post-COVID-19 syndrome. Participants in the study will be randomly assigned to receive either the Ginkgo biloba extract or a placebo. The study will last for 12 weeks, during which participants will take the tablets daily. Throughout the study, participants will undergo various tests to assess changes in their cognitive abilities, such as memory and attention, as well as their overall well-being.

Participants will be monitored for any side effects or adverse reactions to the treatment. The study aims to provide valuable information on whether Ginkgo biloba extract can help improve cognitive function in those affected by post-COVID-19 syndrome. This research could potentially lead to new treatment options for individuals experiencing long-term cognitive issues after recovering from COVID-19.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying a history of COVID-19 infection and the presence of cognitive impairment associated with post-COVID-19 syndrome.

    Eligibility is determined based on specific criteria, such as age, diagnosis of post-COVID-19 syndrome, and cognitive problems persisting for at least two months.

  2. Step 2

    Randomization

    Participants are randomly assigned to receive either the Ginkgo biloba extract EGb 761® or a placebo. This process is triple-blind, meaning neither the participants, the healthcare providers, nor the researchers know who receives the actual treatment or the placebo.

  3. Step 3

    Medication administration

    Participants take the assigned medication orally. The Ginkgo biloba extract EGb 761® is administered as a 240 mg film-coated tablet once daily.

    The duration of the medication administration is up to 12 weeks.

  4. Step 4

    Follow-up assessments

    Participants undergo follow-up assessments at Week 6 and Week 12. These assessments measure changes in cognitive function and other symptoms.

    Tests include the digit span forward and backward test, verbal fluency test, and others to evaluate memory and executive functioning.

  5. Step 5

    Questionnaire evaluations

    Participants complete questionnaires at Week 6 and Week 12 to assess anxiety, depression, and other symptoms. These include the Generalized Anxiety Disorder-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9).

    Additional evaluations include the 11-point box scale for vertigo and tinnitus, and other specific questionnaires.

  6. Step 6

    Safety monitoring

    Throughout the trial, participants are monitored for any adverse effects or reactions to the medication. This includes tracking any side effects or health changes.

  7. Step 7

    Completion of trial

    Upon completion of the 12-week period, participants conclude their involvement in the trial. Final assessments are conducted to evaluate the overall impact of the treatment.

Who can join the trial?

6 criteria

  • Must be a male or female outpatient, aged 18 years or older at the time of signing the informed consent form.
  • Must have a diagnosis of Post-COVID-19 Syndrome (PCS) based on the World Health Organization's definition. This means having a history of probable or confirmed COVID-19 infection, with symptoms continuing for at least 3 months from when COVID-19 symptoms started. These symptoms should last for at least 2 months and cannot be explained by another diagnosis. They must affect daily life, as shown by a physician-rated post-COVID functional status scale score between 2 and 4. Symptoms can be new after recovering from the initial COVID-19 illness or continue from the initial illness, and they may come and go or get worse over time.
  • Must have a history of probable or confirmed COVID-19 infection, confirmed by at least one of the following: a positive PCR test at the time of infection, a positive antigen test at the time of infection along with clinical or epidemiological criteria, a physician's diagnosis based on a positive PCR or antigen test along with clinical or epidemiological criteria, presence of specific antibodies (anti-N IgG or anti-S IgG) in unvaccinated participants.
  • Must have ongoing subjective cognitive problems for at least 2 months, related to PCS and starting after the COVID-19 infection.
  • Must have objective cognitive impairment, which means having difficulties in at least one of the following two areas of thinking: memory (tested by the California Verbal Learning Test, with results below the 50th percentile for age and education) and executive functioning (tested by the Trail-Making Test part B, with results below the 50th percentile for age and education).
  • Must have mild to moderate anxiety or depressive symptoms, defined as a Generalized Anxiety Disorder-7 (GAD-7) score between 5 to 14 and/or a Patient Health Questionnaire-9 (PHQ-9) score between 5 to 19.

Who cannot join the trial?

4 criteria

  • Individuals who do not have cognitive impairment related to Post-COVID-19 Syndrome cannot participate. Cognitive impairment means having trouble with memory, learning, concentration, or making decisions.
  • Participants must be within the specified age range for the study. If you are outside this age range, you cannot join.
  • Both males and females can participate, but if you do not identify as either, you may not be eligible.
  • If you belong to a group considered vulnerable, you may not be able to participate. A vulnerable population includes people who might need special protection or care.
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Investigated drugs

Ginkgo Biloba Extract EGb 761: This is a natural extract derived from the leaves of the Ginkgo biloba tree. It is often used to support brain health and improve cognitive function. In this clinical trial, the extract is being tested to see if it can help improve cognitive impairment in people who have experienced post-COVID-19 syndrome. The study aims to determine if this extract can positively affect memory, attention, and other cognitive abilities in participants.

What is already known about the treatment

Ginkgo Biloba Extract EGb 761® – This medication is administered orally in the form of tablets. It is currently being studied in clinical trials for its potential benefits in treating cognitive impairment associated with post-COVID-19 syndrome. The main therapeutic indication is to improve cognitive function in individuals experiencing cognitive difficulties after recovering from COVID-19. At the molecular level, Ginkgo Biloba Extract is believed to enhance blood flow to the brain and possess antioxidant properties, which may protect nerve cells from damage. It is classified as a herbal supplement with potential cognitive-enhancing effects.

Investigated diseases

Cognitive Impairment Associated with Post-COVID-19 Syndrome – This condition involves difficulties with thinking, memory, and concentration that occur after recovering from COVID-19. Individuals may experience problems with attention, processing information, and recalling memories. These cognitive challenges can vary in severity and may affect daily activities and work performance. The impairment is often described as a "brain fog," where mental clarity is reduced. Symptoms can persist for weeks or months after the initial COVID-19 infection. The exact cause of this cognitive impairment is not fully understood, but it is believed to be related to the body's response to the virus.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-517199-39-00Protocol codeD.01.02.3.03Estimated enrolment400 patientsSponsorDr. Willmar Schwabe GmbH & Co. KG

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