Revitalizing Senses: Evaluating Cerebrolysin’s Effectiveness in Treating Persistent Chemosensory Dysfunctions Post-COVID-19


In the wake of the COVID-19 pandemic, a significant number of patients have been plagued by persistent smell and taste disorders, namely anosmia and ageusia. This study evaluates the effectiveness of Cerebrolysin—a neurotrophic factor (NTF)—combined with sensory training in treating these conditions. The trial demonstrates promising results, highlighting Cerebrolysin’s potential in facilitating sensory recovery.


Persistent chemosensory dysfunctions post-COVID-19 significantly deteriorate quality of life, with many patients experiencing long-lasting symptoms despite recovering from the initial viral infection. This randomized clinical trial investigates the therapeutic potential of Cerebrolysin, known for its neuroregenerative properties, in conjunction with olfactory and gustatory training exercises.

Research Design and Methods

The study enrolled 250 patients suffering from prolonged smell and taste disorders post-COVID-19, categorized into two groups. Group 1, consisting of 150 patients, received 5 ml of Cerebrolysin intramuscularly daily for five days a week, along with sensory training, for a duration of 8 to 24 weeks. Group 2, with 100 patients, engaged only in sensory training. Patient outcomes were evaluated using clinical questionnaires, Sniffin’ sticks (odor tests), taste strips (taste tests), flavor identification tests, and global rating scales.


Patients exhibited persistent sensory disorders for an average duration of 11.7 months, with symptoms ranging from 6 to 24 months. Notably, 66.8% of patients developed parosmia a few months (average 3.6 months) after initial anosmia. Complete recovery was observed in 61.5% of patients in Group 1 who received Cerebrolysin therapy, with an additional 17% showing partial recovery. In contrast, patients in Group 2, who only underwent training, did not experience any recovery. These results underscore Cerebrolysin’s efficacy in not only enhancing sensory recovery but also in significantly improving the cure rate to over 60%.


The findings from this trial suggest that Cerebrolysin can significantly improve the recovery rate of chemosensory functions in patients with post-COVID-19 sensory losses. This effect is attributed to Cerebrolysin’s capability to initiate neuronal regeneration and reorganize sensory epithelia, marking it as a viable treatment option for managing persistent olfactory and gustatory dysfunctions.

Trial Registration

This trial was registered under the identifier NCT04830943, underscoring its adherence to ethical standards and scientific rigor.

Ethics, Declarations, and Data Availability

The study protocol was approved by the medical research ethics committees of the Faculty of Medicine, Assiut University, under the ID: COVID-NGF/AUH_SAH/2020. All participants provided written informed consent. Data from the study are available upon request through the principal investigator’s ORCID link, ensuring transparency and accessibility for further research.

Author Contributions

Sherifa Ahmed Hamed was instrumental in the overall design, implementation, and analysis of the trial, and took the lead in manuscript preparation. Mohamed Azzam Abdel-Razek Ahmed contributed significantly to patient evaluation and data verification, ensuring the integrity of the results.

APPENDIX – Cerebrolysin: A Detailed Overview

Cerebrolysin is a neuropeptide preparation derived from pig brain proteins, specifically designed to aid in neurological recovery. It is primarily utilized for the treatment of stroke, Alzheimer’s disease, and other types of cognitive impairment. The drug operates on a multifaceted mechanism involving neuroprotection, neuroplasticity, and neurogenesis, which contribute to its therapeutic effects.

Composition and Properties

Cerebrolysin contains low-molecular weight peptides and amino acids which can cross the blood-brain barrier. These peptides exert their effects directly on the central nervous system, promoting neuronal growth and survival. The exact composition of Cerebrolysin, which is a complex mix of biologically active peptides, plays a crucial role in its efficacy.

Indications and Usage

Cerebrolysin is used as adjunct therapy for conditions such as:

  • Alzheimer’s disease: It helps in cognitive preservation and slowing the progression of symptoms.
  • Stroke: Cerebrolysin is employed to enhance recovery post-stroke, improving motor functions and overall patient outcomes.
  • Traumatic brain injury (TBI): The medication supports brain repair mechanisms, potentially reducing long-term neurological deficits.
  • General cognitive impairment: It offers symptomatic relief and functional improvements in various forms of brain degeneration.

Clinical Efficacy and Studies

Several clinical studies have demonstrated the effectiveness of Cerebrolysin:

  • In Alzheimer’s disease, it has shown to improve cognitive function and patient quality of life, particularly in early and moderate stages.
  • For stroke recovery, Cerebrolysin has been noted to improve functional outcomes when administered early, with benefits in motor function and independence.
  • In TBI cases, it supports brain recovery processes, potentially minimizing cognitive and functional deficits.

For instance, a registry study to assess the safety and effectiveness of Cerebrolysin in routine treatment of acute ischemic stroke involved over 1800 participants and highlighted positive outcomes in the management of stroke​ (Home –​.

Dosage and Administration

Cerebrolysin is administered via intravenous or intramuscular injections. The dosage and duration of the treatment depend on the severity and type of the neurological condition. Treatment protocols can vary significantly, from intensive daily treatments to periodic maintenance doses.

Safety and Side Effects

While generally well-tolerated, Cerebrolysin can cause side effects such as headaches, dizziness, agitation, and hypersensitivity reactions. Its use is contraindicated in patients with epilepsy and renal impairment due to potential complications​ (Cerebrolysin)​​​.

Mechanism of Action

The primary action of Cerebrolysin is to enhance neurotrophic activity in the brain which supports neuronal growth and repair. It mimics the action of endogenous neurotrophic factors that regulate neuron development, survival, and differentiation. Moreover, its neuroprotective properties prevent neuronal damage from metabolic toxins and oxidative stress.

Cerebrolysin represents a significant advancement in the treatment of neurological disorders, offering hope for improved outcomes in conditions where treatment options were previously limited. Its role in enhancing neuroplasticity and facilitating recovery in various neurodegenerative and acute neurological conditions makes it a valuable tool in neurology and rehabilitation medicine.

For more detailed information on Cerebrolysin and related studies, please refer to specialized medical resources and clinical trial registries.

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