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Do Soaps Really Kill The Viruses? If So, How?

Team StoryWeavers|February 07, 2022, 13:17 IST|

Parents, doctors and even soap advertisements all advise us to wash our hands with soap after we come home and before we eat. Washing our hands with soap is a vital hygiene practice, especially during flu seasons. The reason behind this practice is the soap’s ability to “kill” germs.

It’s astonishing that a thing as mundane as soap can be our best defense against the deadliest of viruses. So, what gives soaps the ability to shield us against germs? And do they really “kill” the virus?

What is soap?

Soap is a slippery thing we use to wash our hands. Right… but chemically speaking, soaps are made of some kind of fat or oil, water and some kind of alkaline substance, such as a type of salt. Alkaline means opposite to acidic. When the fat and the alkaline ingredient are mixed together with the help of some water, there is a chemical reaction, called saponification. Soap is the result!

When did humans start using soaps?

Box for Amigo del Obrero (Worker’s Friend) soap from the 20th century. Photo by: Museo del Objeto del Objeto

Ancient humans have been making soaps for thousands of years using animal fat and wood ash. It probably began with an accident thousands of years ago. According to one legend, rain washed the fat and ash from frequent animal sacrifices into a nearby river, where they formed a lather with a remarkable ability to clean skin and clothes. 

Perhaps the inspiration had a vegetal origin in the frothy solutions produced by boiling or mashing certain plants. However it may have happened, the ancient discovery of soap altered human history. Although our ancestors could not have foreseen it, soap would ultimately become one of our most effective defenses against invisible pathogens.

The Chemistry of Soap

All soaps are essentially surfactants (surface-active agents) and are made of amphiphilic molecules. This means that they have two parts: a hydrophilic (water-loving) head and a hydrophobic (water-hating) tail.

These molecules, when suspended in water, alternately float about as solitary units, interact with other molecules in the solution and assemble themselves into little bubbles called micelles, with heads pointing outward and tails tucked inside.

How does soap work?

To understand how soaps destroy germs, you must first understand how they work under regular circumstances. With that in mind, let’s take a look at how soaps and detergents wash clothes so effectively.

Detergents can easily remove dirt and grease on clothes due to the action of the amphiphilic molecules. When you mix detergent into the water, the polar head orients itself towards the water phase. Whereas, in order to run away from water molecules, the hydrophobic tail orients itself towards non-polar molecules, such as oils.

The hydrophobic tail attaches itself to the dirt and oil stains to prevent contact with water. At the same time, the hydrophilic head links itself to the water molecule. The soap then yanks the oil off the surface by orienting itself in a circular structure around oil particles, known as micelles. These micelles escort the oil molecules to the surface of the water. Here, the lather of the soap traps the dirt and oil, allowing it to rinse away with water.

However, what does this have to do with viruses?

How do soaps break down viruses?

In a manner of speaking, viruses are similar to oil molecules. How, you ask? Well, the virus is essentially genetic material wrapped in a protective layer, called the envelope. These envelopes are made of fats or, scientifically speaking, lipid bilayers. They also contain a very integral part of the virus: protein spikes. These spike proteins latch on to the receptors present on the host cells, allowing the virus to infect them.

Viruses with a lipoprotein envelope include the Ebola virus, H1N1 influenza virus, herpes and the currently trending- coronavirus, just to name a few.

Just as in the case of washing grease stains off clothes, soap molecules attach themselves to the virus and other germs. When you wash your hands with soap and water, the hydrophobic tail of the soap starts looking for an area to get away from the water molecules. When they find the virus, the soap molecules start surrounding it. The hydrophobic tail sticks to the lipid bilayer wall of the virus and plucks it out from a given surface, such as your skin.

It doesn’t stop there. The hydrophobic tail further penetrates the virus, seeking to further get away from the water. Just like popping a bubble with a pin, the tail pops open the outer wall of the virus. This splits the virus apart, causing its contents to release into the soapy water. The remains of the virus rinse away when you wash your hands.

Do soaps “kill” the virus?

Well, yes and no. Soaps simply tear the virus apart and remove it from the surface.

Think of this as the soap giving the virus a good rub-a-dub-dub. So much so that at the end of it, the virus still technically remains, but only in pieces, without cell walls and spike proteins. 

But, if there is no cell wall holding the contents of the virus together, is that even really a living virus? So, yes, in a way you can say that soaps kill the virus. 

So, wash those hands kids!

People typically think of soap as gentle and soothing, but from the perspective of microorganisms, it is often extremely destructive. A drop of ordinary soap diluted in water is sufficient to rupture and kill many types of bacteria and viruses, including the new coronavirus that is currently circling the globe.

Contrary to what many believe, soaps are much more effective in killing germs than alcohol-based sanitizers. Don’t get us wrong, sanitizers do kill viruses and germs, but they cannot wash the virus away. Instead, they leave behind sterile dirt and dead viruses on your hands.

Hand sanitizers can be a good substitute for soap and water. However, when possible, one must opt for soap and water to clean the hands.


About the Author

Raza has been writing since 2008, be it fiction, poetry, or articles on science, politics, and history. He believes that words can change the world, and he uses them to inspire and empower people through his writing. When he is not working, he is watching nature documentaries or playing with his cats.

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