Inclusion Criteria:  Adults of either gender aged 18 to 65 years inclusive. Patients within 4-12 weeks of the confirmed COVID-19 onset . Symptoms of asthenia that appeared during or after an acute new coronavirus infection (COVID-19), persisting from 4 to 12 weeks from the onset of coronavirus infection. Presence of asthenia (≥36 on the FSS scale). Patients who agreed to use a reliable method of contraception during the study (for men and women with reproductive potential). Presence of a signed information sheet and informed consent form for participation in a clinical trial.  Exclusion Criteria:  History / suspicion of cancer of any localization (with the exception of benign neoplasms). More than 75% of lung tissue damage during the period of COVID-19 disease (CT 4). Cerebrovascular diseases with the development of moderate to severe cognitive impairments. Uncontrolled arterial hypertension characterized by the following blood tension values: systolic blood pressure > 180 mm Hg and/or diastolic blood pressure > 110 mm Hg. Myocardial infarction, stroke in the previous 6 months. Nervous system disorders with persistent neurological impairment. Autoimmune diseases. Decompensated diseases of the cardiovascular system, liver, kidney, gastrointestinal tract, and metabolic, respiratory, endocrine or hematological diseases, peripheral vascular disorders. Any severe comorbidity which, in the opinion of the investigator, may affect patient participation in the clinical trial. Hypersensitivity to any of the components of the study drug. Hereditary lactose intolerance, lactose malabsorption, including congenital or acquired lactase or other disaccharidase deficiency, galactosemia. Pregnancy, breast-feeding; childbirth less than 3 months prior to the inclusion in the trial, unwillingness to use contraceptive methods during the trial (for men and women with reproductive potential). Patients, who, from the investigator's point of view, will not comply with study observation requirements or study drug administration procedures.. Prior history of mental illness, alcoholism or drug abuse, that the investigator's opinion, will interfere with successful study procedures. Use of any medications listed in "Prohibited concomitant treatment" within 1 week before enrollment. Participation in other clinical studies within 3 months prior to enrollment in the study. Patients who are related to any of the on-site research personnel directly involved in the conduct of the trial or are an immediate relative of the study investigator. "Immediate relative" means husband, wife, parent, son, daughter, brother, or sister (regardless of whether they are natural or adopted). Participants who work for OOO "NPF "MATERIA MEDICA HOLDING" (i.e. the company's employees, temporary contract workers, designated officials responsible for carrying out the research or any immediate relatives of the aforementioned).