if a hand sanitizer or soap kills up to 99.9% of germs, does lathering your hands with huge amounts of soap make any difference vs a simple pump or two of soap?

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In: 40

Answer 1

While soap helps, duration matters more for reasonably clean hands. After 30 seconds of thorough washing, your hands will be reasonably clean, even without soap.

Answer 2

No, you just need a minimum amount of soap to cover all the surface. The important factors are duration and covered area. Even temperature is not that important. But you can rinse, and wash a second time if your hands were very dirty.

Answer 3

It’s important to remember that while the marketing blurb says “99.9% of germs,” that doesn’t mean it kills 99.9% of *all* germs. They only need to show that it works on a specific subset of germs in order to make that claim.

What’s more: https://xkcd.com/1161/

Answer 4

A simple pump or two of soap is enough. More than that will just go to waste. The most important things are time and friction.

Washing your hands gets rid of germs both chemically and physically. The soap or sanitizer kills the germs it contacts (chemical,) but this is not instant. More time = more germs killed. Vigorously rubbing your hands together, with soap and water, washes germs off of your hands and down the drain (physical.)

Recent research shows that the temperature of the water is less important than we once thought.

Answer 5

While quantity of soap doesn’t really have an impact, people in general are absolutely appalling at washing their hands. There’s a reason there’s a dedicated process to follow for hand washing on entering a sterile environment, large amounts of the hands are routinely missed in standard hand washing. If there is more soap, it has to be spread across a larger surface of the hands, so it will reduce your bacterial load, but that is due to reasons unrelated to the actual efficacy of the soap.

Answer 6

More soap makes it easier to spread it across your hands but that’s about it (unless you don’t use enough of course)

Answer 7

“Up to 99.9%” is just legalese for “basically everything but you can’t sue us if you manage to find a single living germ after using our sanitizer”.

You just use enough so that it covers every bit of skin.

Answer 8

It should be noted that hand sanitizer works best when the mix is about 71% alcohol to 29% water, higher alcohol actually makes it sanitize less.