Coronavirus: How hand sanitisers protect against infections – Compound Interest

There are a few criteria that hand sanitisers need to meet to be most effective. Alcohol-based sanitisers are more effective than their non-alcohol-based counterparts. However, the alcohol percentage by volume needs to be at least 60%. Below this, they’re less likely to kill the bacteria and viruses on your hands.

The potency of alcohol-based hand sanitisers increases with the percentage by volume of alcohol. So higher percentages are likely to be better. However, very high concentrations (above 95%) are less effective. This is because proteins aren’t denatured as easily when there isn’t water around.

Another key factor is the volume of hand sanitiser used. It needs to be enough to cover all areas of both hands — otherwise, you’re leaving areas where viruses and bacteria could continue to linger. To properly coat your hands, you need to use about 3 millilitres of sanitiser (approximately a palmful).


CompoundChem is a site authored by Andy Brunning, a chemistry educator in the UK.

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