Does soap need to be antibacterial to kill a virus?

Never before has humble hand washing emerged as such a hero. It’s our first line of defence in our battle against coronaviruses like COVID-19. And unlike masks, eye shields or vaccines, soap is something that’s accessible and affordable for most of us.

Respected public health information sources including the Mayo Clinic suggest that antibacterial soaps and hand washes are no more effective than regular soap alternatives at getting rid of COVID-19. The Center for Disease Control also states that alcohol-based hand sanitisers are not effective against all types of germs. And regular soap may be better for our health in the long-term.

How soap and water beat the bad bugs

Using water alone may get rid of visible dirt, but the microscopic nanoparticles of viruses and bacteria get stuck in the crevices of our wrinkles and fingerprints. Here’s where soap comes in.

All soaps – whether they’re liquid, bars, or foams – are made up ‘soap molecules’. These molecules have a dual nature: with both hydrophilic (water-loving) tails and hydrophobic (water-hating) heads. When introduced to water, the water-attracting parts point outward to bond with water, while the tails turn inwards to avoid the water, instead bonding with fats and oils, catching dirt and germs in microscopic bubbles called micelles.

COVID-19 is a coronavirus – meaning it’s encased in a protective fatty coating. Imagine a pin popping a balloon: the water-repelling end of the soap molecule bonds with this coating, stabbing it, and leaving the virus deflated. Soap then lifts the dead virus away from skin within its micelles, so you can wash it away.

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How to get the best results with soap and water

When you lather and scrub hands well with soap for at least 20 seconds, the pin-shaped molecules will penetrate the types of viruses (including coronaviruses like COVID-19) that protect themselves with a fatty membrane.

The New Zealand Government’s COVID-19 website recommends a particular hand washing routine. It involves scrubbing wrists, palms and backs of hands, then interlacing the fingers, making fists around each thumb and rubbing fingertips into palms. Lathering every surface of the hands is the key to lifting them away from skin so they can be washed down the drain. The temperature of the water doesn’t matter either – it can be cold or warm.

The good news is that any soap will kill coronaviruses if you use this method. But if you find your hands are becoming dry or sensitised from all this hand washing, try using a gentle, plant-based soap that’s been specially formulated without fragrance for sensitive skin.

The dangers with antibacterial gels and soaps

Bacteria are quite different to viruses. One problem with soaps that are sold as ‘antibacterial’ is that they’re no more useful in the fight against COVID-19 than any other soap. Antiseptic gels are only effective against the virus if they contain more than 60% alcohol, which can be very drying to skin. And any bacteria that survive these agents can evolve to become resistant to antibacterial products in the future.

Overusing ‘antibacterial’ products containing ingredients like Triclosan is not only potentially harmful in itself, these ingredients can also reduce the good bacteria that live on our skin and in our gut. A lack of diverse gut flora (aka the gut microbiome) is linked to many human diseases, including diabetes, arthritis, autoimmune illnesses and increased allergic reactions and sensitivities. Check out this blog post by Kaytee Boyd, for ways to naturally restore and support a healthy microbiome.