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Umifenovir is an influenza antiviral registered in Russia and China; laboratory work shows it interferes with the membrane fusion step that lets influenza enter a cell, but the clinical trials behind its use are almost all domestic and no regulator in the European Union or the United States has ever approved it.
- Influenza antiviral registered across Russia and China
- Locks influenza haemagglutinin in laboratory work
- Blocks the membrane fusion step in vitro
- A real and specific effect in the dish
- Harm looks low in practice
- Twenty years of use across two large markets
- The mechanism against influenza is real and structurally solved: X-ray crystal structures of arbidol bound to H3N2 and H7N9 haemagglutinin show it wedges into a hydrophobic cavity at the protomer interface in the HA stem and locks the prefusion conformation, preventing the pH-triggered rearrangement that drives membrane fusion [1]. Mechanism is not the weak point.
- There is NO Cochrane review of umifenovir or arbidol for influenza or for COVID-19. Cochrane's only contact with the drug is as a comparator arm in one of 25 trials in its favipiravir review. Any claim of a favourable Cochrane assessment of arbidol is false.
- The Western meta-analytic verdict on COVID-19 is negative. Huang et al. pooled 12 studies and 1,052 patients and concluded there is 'no evidence to support the use of umifenovir for improving patient-important outcomes'; no effect on nucleic acid negative conversion time, day-7 negativity, composite endpoint, fever alleviation, cough alleviation or length of stay [2].
- Amani et al. pooled 16 studies and reached the same conclusion, and additionally found arbidol was associated with MORE adverse events than non-antiviral treatment (RR 2.24, 95% CI 1.06-4.73) [3].
- Where arbidol looks favourable it is only against another failed drug: it beat lopinavir/ritonavir on day-7 and day-14 PCR conversion and mortality [4], which is a comparison to a comparator that itself showed no clinical or virological benefit. This is the single most important caveat to state.
- Umifenovir is registered and heavily used in Russia and China. It has never been approved by the FDA or the EMA and appears in no Western influenza or COVID-19 treatment guideline.
Mechanism
In vitro it intercalates into membrane lipids and binds a hydrophobic pocket in influenza haemagglutinin, stabilising the protein so the low pH conformational change that drives endosomal fusion cannot happen and the virus stays trapped. Whether that in vitro effect produces a meaningful clinical benefit at achievable human concentrations is exactly what the international evidence does not settle.
receptor fingerprint
Influenza A haemagglutinin (HA), trimer stem hydrophobic cavity at the protomer interfaceFusion inhibitor; binds and acts as 'molecular glue' stabilising the prefusion HA conformation
Cell membrane lipid bilayer / endosomal membraneNon-specific membrane interaction and intercalation
SARS-CoV-2 spike / ACE2 interactionProposed inhibition (computational and docking work only)
Safetyrisks and cautions, not medical advice
a registered antiviral medicine rather than a supplement, whose efficacy has not been established to international standards, so taking it in place of a treatment that works is the practical hazard
Subjective profileweighing the evidence above
An in vitro mechanism can be elegant and still not matter, and this is the textbook case. Locking influenza haemagglutinin so it cannot make the low pH conformational change is a real and specific effect in a dish; twenty years of domestic sales have not produced the independent trial that would show it shortens an illness in a person. Harm looks low, so the practical risk is not toxicity but substitution. Taking it through a genuine influenza in someone elderly, pregnant or chronically ill, in place of care that has been shown to work, is where an unproven drug becomes a dangerous one.
Where to buy
Suppliers
Vendors carrying Umifenovir, with live product details and codes. Links are affiliate links that support the wiki at no cost to you.
RUPharma🌐
Umifenovir
Research
- 2017first citedStructural basis of influenza virus fusion inhibition by the antiviral drug Arbidol
- 2020meta-analysisEfficacy and safety of umifenovir for coronavirus disease 2019 (COVID-19): A systematic review…
- 2021most recentEfficacy and safety of arbidol (umifenovir) in patients with COVID-19: A systematic review and…
- 1.Structural basis of influenza virus fusion inhibition by the antiviral drug Arbidol
- 2.Efficacy and safety of umifenovir for coronavirus disease 2019 (COVID-19): A systematic review and meta-analysis
- 3.Efficacy and safety of arbidol (umifenovir) in patients with COVID-19: A systematic review and meta-analysis
- 4.Meta-analysis of arbidol versus lopinavir/ritonavir in the treatment of coronavirus disease 2019
- 5.Antiviral Therapeutic Approaches for SARS-CoV-2 Infection: A Systematic Review
5 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
Notes and cautions
- There is no boxed warning because no Western regulator has assessed the drug.
- Umifenovir is generally reported as well tolerated, with the largest COVID-19 meta-analysis finding no significant excess of adverse events versus control (RR 1.29, 95% CI 0.57-2.92) [2]; however, a second and larger meta-analysis found the opposite, a significant excess against non-antiviral treatment (RR 2.24, 95% CI 1.06-4.73) [3], and the two should be presented together rather than choosing the more flattering one.
- Reported adverse effects are mild and mostly gastrointestinal, with transient transaminase elevation.
- The realistic risk here is not toxicity but substitution; using an unproven antiviral in place of a therapy with demonstrated benefit.