Lactic acid could offer antibacterial effects for healthy hand skin barrier

12 Jan 2022 --- Low pH, higher temperature of hands and increased amount of lactic acid (found in sweat) resulted in more substantial skin barrier against Escherichia coli (E. coli) bacteria, finds The Personal Health Care Product Research Laboratory, Biological Science Research Laboratory, and Analytical Science Research Laboratory of Kao Corporation.

The potential for this finding has a dual effect: improved skincare using lactic acid and protecting individuals and others from harmful bacteria. Although Kao only tested E. coli bacteria, it shows the potential for pairing health and safety with care and beauty in the industry.

Kao states that it will use the findings to create technologies that will predict better hand barrier functions, including products to maintain it.

This stands out especially during the COVID-19 pandemic, as lockdowns have caused an increase in care for health and beauty. Sanitizing hands is part of daily routines that need to be reconsidered in terms of care. 

Antibacterial personal care products have had an average annual growth of 49% these past five years, according to Innova Market Insights. 

Additionally, lactic acid has already been shown to have a positive effect on immunity. 

Lactic acid is naturally found on hands which already acts as a barrier to various bacteria and viruses. Enhancing this process by increasing lactic acid will boost natural skin protection. This has no side effects, unlike hand sanitizers which cause dry skin and destroy good bacteria that protects the skin. Kao is producing new hygiene practices by strengthening skin barriers against bacteria and viruses. 

Kao builds on previous findings
The study, now published in Skin Research and Technology, builds on the findings of prior research that suggested lactic acid improves the skin barrier. In the new investigation, Kao applied lactic acid onto the hands of 106 healthy males and females aged between 20-60 years. 

After applying lactic acid, E. coli bacteria in a solution was spread onto the hands. The researchers measured the decrease in E. coli bacteria after one minute of application.

A model study was also conducted using test tubes. Using the same concept carried out on human hands, researchers used the same bacteria and acid to confirm results.

When lactic acid meets E. coli bacteria, it breaks down the bacterial cell membrane, takes over the cell and destroys it, eventually killing E. coli bacteria. This means that infections will not spread as quickly to others by touch.

The lactic acid’s effect was studied at temperatures between 20 and 40°C. The higher the temperature, the more effective the breakdown of cell membranes. 

Edited by Venya Patel