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Soap: The COVID-19 Killer

Many governments and organizations have stressed the importance of washing your hands frequently to reduce the spread of COVID-19. But not many people actually think about how soap and/or hand sanitizer can get rid of this virus. In this article, we'll cover how this works, as well as how you should properly wash your hands.

Image is courtesy of Ketut Subiyanto via Pexels

What is Soap?

Soaps (and other household cleaning items) consist of biosurfactants, which are compounds made by some bacteria and plants. They are composed of a polar, and thus hydrophilic (water-loving) head and hydrophobic (water-repelling) tails. The presence of both hydrophilic and hydrophobic properties makes them amphipathic, similar to phospholipids found in cell membranes.

Based on these biosurfactants' environment, they can form different types of structures and pack together into different shapes through interactions of hydrophobic tails. A particularly common example of this is the micelle, pictured below:

Individual biosurfactant compounds making up a micelle structure (Simply Science)

How Soap Works on COVID-19

Firstly, we need a basic understanding of how COVID-19 functions as an infectious agent. This virus has a lipid membrane and spike (also known as S) proteins on its surface. These proteins can bind to a receptor on the human cell membrane called the ACE2 receptor. And it is this binding that allows fusion between the human and virus membranes, leading to the entry of the virus.

Soap's hydrophobic region interacts with the virus's membrane to break it down and disable it from fusing. This causes the contents of the virus capsule to spill out, which are then immediately contained within a micelle shell formed by the hydrophobic tails of the soap particles.

Additionally, soap can cling to dirt and carry it away. This happens because the hydrophobic tails can attach to the dirt and form a micelle around it. Simultaneously, the hydrophilic heads bind to the water, allowing for the trapped dirt particles to be easily removed.

How biosurfactants get rid of dirt and, more specifically, breakdown COVID-19

(Smith et al. 2020)

Soap vs. Hand Sanitizer

One of the main differences between soap and hand sanitizer is that soap is made of biosurfactants, whereas hand sanitizer uses alcohol. This alcohol can be detrimental if used too often, as it can cause discoloration and damage to the skin. Additionally, hand sanitizer doesn't actually remove all of the germs and can be ineffective if your hands are dirty. Soap, on the other hand, has benefits over hand sanitizer as it has the ability to lather, which helps remove substances.

Because of all of the above reasons, the CDC states that soap and water is a better method of washing your hands than hand sanitizer is.

How to properly wash your hands

Now that you know how soap works and how important it is, do you know how to wash your hands properly? Most people rub their palms together and go over the back of their hands, but this can miss some important areas, including under and around the nails, the thumbs, and between the fingers. To reach these areas, it's important to gather your fingers together and rub the surfaces of your fingernails within the palm of your opposite hand. Also, make sure to rub your thumbs between your fingers and interlock your fingers several times when washing your hands. For a visual guide, visit this Youtube video


Hand soap is one of the main defences against COVID-19, as it uses ingredients that trap the virus particles and remove them from your hands. However, you may not have access to a sink and some soap, making hand sanitizer your next best option. As long as you remember to cleanse your hands as often as possible, you will help fight this pandemic!


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Article Authors: Vanessa Wong, Valerie Shirobokov

Article Editor: Edie Whittington