What concentration of alcohol is most effective in an Alcohol-based Hand Rub (ABHR)?

The most effective concentration of alcohol in an Alcohol-based Hand Rub (ABHR) is between 60-95%. This range is critical for ensuring that the hand sanitizer effectively inactivates a broad spectrum of pathogens, including bacteria and viruses. Alcohols at this concentration achieve the optimal balance of antimicrobial efficacy and safety for skin use.

A concentration of 60% alcohol is generally considered the minimum effective level for antimicrobial action, while concentrations approaching 95% offer strong germicidal activity. However, solutions with very high concentrations of alcohol (close to 100%) can result in reduced effectiveness due to rapid evaporation and insufficient time for the alcohol to penetrate the cell membranes of microorganisms.

This range ensures that the alcohol remains wet on the hands long enough to effectively kill pathogens. Additionally, the presence of water in the formula helps facilitate the denaturation of proteins in the microorganisms, enhancing the overall antimicrobial effect. Hence, the choice of 60-95% is substantiated by both scientific data and clinical practice guidelines.