Hand sanitiser is highly effective in killing a broad spectrum of bacteria and viruses, including many that cause illnesses. However, while hand sanitiser is a valuable tool, it may not be as effective as thorough hand washing in some situations. Hand washing with soap and water for at least 20 seconds is recommended when your hands are visibly dirty or contaminated with certain substances.

The longevity of hand sanitiser on your hands depends on several factors, including the product's alcohol content and the volume applied. In general, a standard hand sanitiser with at least 60% alcohol should remain effective for about 20 seconds to a minute after application. During this time, it needs to stay wet on your hands to be effective. Once it has evaporated or dried on your skin, its germ-killing effectiveness diminishes. If you feel your hands have become dry or if you've touched potentially contaminated surfaces, it's advisable to reapply hand sanitiser.

In most cases, washing your hands with soap and water after using hand sanitiser is not necessary. Hand sanitiser is designed to kill germs and reduce the risk of infection when soap and water are unavailable. However, there may be situations where hand washing is still recommended. For instance, if your hands are visibly dirty, contaminated with certain chemicals, or if you've been in contact with someone who is sick, it's advisable to wash your hands thoroughly with soap and water. Otherwise, using hand sanitiser can be an effective and convenient way to maintain hand hygiene when you're on the go.