Hankkija FFI has successfully promoted the use of resin acids in farm animal feeds since 2014. The improved performance of broiler chickens, sows and piglets has been scientifically proven, as are the associated favorable changes in the immunological status and microbiota of these animals.

Now the resin acids are proving to be even more versatile antimicrobial molecules than previously anticipated. The efficacy of a resin-based product against enveloped viruses was recently proven in a peer-reviewed scientific article (Bell et al., 2021). The study was conducted at the Queen’s University Belfast, Northern Ireland, in the research group of professor John McGrath, in collaboration with Hankkija FFI and Forchem Oy.

This time, the intended application was not farm animal feeds, but rather the use of resin acid-containing soap, rosin soap, in surface disinfectants, soaps or hand gels. As we have so well learned during the Covid-19 pandemic, preventing viral infections by high level of hygiene is very important not only for the individual but also for the community.   

The study of Bell et al. (2021) proved that rosin soap effectively inactivates human enveloped viruses such as influenza A virus, respiratory syncytial virus, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also called Covid-19.

The efficacy of rosin soap was studied by treating the virus particles with rosin soap at different concentrations, times and ambient temperatures, and then testing the ability of the treated viruses to infect cultured cells. 

An astonishing 100,000-fold reduction in infectivity of influenza A virus was obtained with a 5-min contact time of 2.5% rosin soap solution with the virus. The effect was similar at temperatures of 4°, room temperature, and 37°C, and for contact times of 5, 15 and 30 min. For the RSV and Covid-19, the authors stated that rosin soap at 2.5% brought essentially all infectivity to below the limit of detection, suggesting nearly complete inhibition of infectivity.

According to the authors, the ability of rosin soap to inactivate enveloped viruses is likely based on their ability to disrupt the phospholipid layer of the viral envelope. The envelope has a role in the ability of the viruses to enter their target cells. Without an intact envelope, SARS-CoV-2 and other enveloped viruses lose their infectivity.

In conclusion, the study suggested that rosin soap is very effective against enveloped viruses such as Influenza A virus and the Covid-19 virus. The potential of resin acids against farm animal viruses remains to be investigated.


Stephen H. Bell, Derek J. Fairley, Hannele Kettunen, Juhani Vuorenmaa, Juha Orte, Connor G. G. Bamford, John W. McGrath (2021) Rosin Soap Exhibits Virucidal Activity. Microbiol Spectrum, 9(3): e01091-21. doi: 10.1128/spectrum.01091-21