You can find hand sanitiser everywhere these days: in shopping streets, at cash registers and now also at all VUB campuses and exam locations. But what’s the correct way to use hand sanitiser? And can hand sanitiser damage your skin if you use it too much? We took our questions to emeritus professor Vera Rogiers from the In Vitro Toxicology and Dermato-Cosmetology department.

Text: Linda A. Thompson

The thing that makes hand sanitiser disinfecting is the amount of alcohol it contains. Hand sanitiser contains a minimum of 70% alcohol and a maximum of 90 %. “Hand sanitiser should also contain water so that the alcohol can do its work properly,” Rogiers explains. “A hand sanitiser that consists of 100% alcohol isn’t better, quite the opposite.”

In addition to alcohol and water, alcohol also contains a 2 to 3% amount of glycerin. This glycerin is an absolute must, Rogiers explains, since it ensures the skin is left hydrated. Without glycerin, hand sanitiser would be really hard on the skin.

Destroying virus particles

‘Disinfecting’ means removing or destroying virus particles and bacteria. How does this process work exactly? Virus particles have a layer of fat to which proteins are attached, Rogiers explains. When you use hand sanitiser, the strong alcohol in the hand sanitiser dissolves these fats and denatures the proteins. Denaturation means that the proteins lose their structure. The result is that the virus particle is destroyed.

For a hand sanitiser to be effective, you have to use it the way you would a traditional hand wash product. In other words, wash for 20 to 30 seconds, rinse between your fingers, don’t neglect your thumbs or fingertips, and so on. Rogiers points out that you also have to let the hand sanitiser dry naturally. “There’s no point to using hand sanitiser if you then immediately wipe it off with paper – you have to give the hand sanitiser the time to dissolve the fat layer around the virus particle and in this way destroy it.”

You have to give the hand sanitiser the time to dissolve the fat layer around the virus particle and in this way destroy it. - Vera Rogiers

Sanitisers, liquids and wipes

In addition to hand sanitiser, you can also find liquid hand sanitiser and disinfectant wipes in supermarkets and pharmacies. What is the difference between all these products? “When it comes to their effectiveness, there is no difference,” Rogiers explains. “It’s just that hand sanitiser is a bit easier to use since it contains a thickening agent. As a result, it’s easier to rub out the hand sanitiser without it escaping through your fingers – which does happen with the liquid version.” Alcohol-containing disinfectant wipes also work the exact the same way hand sanitiser does. But their solid form makes them the ideal solution to wipe down flat surfaces that have been touched by others like doorknobs, arm rests and keyboards.

Hand sanitiser versus soap

You should keep in mind, however, that it’s best to wash your hands with a handwash product under running water. You should only resort to a disinfectant hand sanitiser when this isn’t possible. “If you disinfect your hands every time, you’ll remove the good micro-organisms on your skin and cause your skin to become completely imbalanced,” Rogiers explains. The result is that your hands will quickly become irritated with eczema and chapped skin.“And such hands are more accessible to the virus because the virus particles can more easily penetrate them.”

If you disinfect your hands every time, you’ll remove the good micro-organisms on your skin and cause your skin to become completely imbalanced. - Vera Rogiers

So wash your hands with ‘soap’ whenever possible. Or, rather, wash them with syndet products, Rogiers clarifies. “We now keep getting the message that we should wash our hands with soap, but soap is a legally protected term that refers to a particular substance. Real soap is for instance the Sunlight soap that you used to find in many homes. Real soap is harsh. This means that soap is just about the worst thing you could use if you have to regularly wash your hands. Instead, you should use ‘syndets’ or synthetic detergents – for instance, sulfosuccinates and isethionates. Examples are the Dove you can buy in supermarkets and the Eucerin bars sold in pharmacies.”

Antibiotic resistance

You sometimes also hear that disinfectant hand sanitisers are deteriorating our resistance to antibiotics. Does this mean that using hand sanitiser can be risky in the long run? Nope, says Rogiers. “It’s true that there are concerns that resistance may develop due to large-scale use of disinfectants, but these concerns are not over use of alcohol, but over inappropriate use of antibacterial disinfectants like chlorhexidine (found in Hibiscrub), Povidone-iodine (found in iso-Betadine) and chloroxylenol (found in Dettol Medical). Because we’re getting the message that it’s important to disinfect to combat the spread of the coronavirus, people are now resorting to all sorts of antibacterial disinfectants. But this means that you’ll constantly be removing all sorts of bacteria that don’t at all need to be removed. Antibacterial disinfectants have moreover not been proven to have an effect on viruses.”

Antibacterial disinfectants have moreover not been proven to have an effect on viruses. - Vera Rogiers

Steer clear of perfumes

The outbreak of the coronavirus has exploded the demand for hand sanitisers, and some manufacturers are now trying to seduce consumers with hand sanitisers with perfumes, essential oils and plant ingredients. Think before you buy these, Rogiers says. “We know that fragrance compounds and perfumes are the lead driver of allergic reactions and that they can provoke eczema. So stay away from such products because using them will increase your risk for all sorts of allergies.”

Fragrance compounds and perfumes are the lead driver of allergic reactions and that they can provoke eczema. So stay away from such products. - Vera Rogiers

No scientific breakthroughs have been made in the area of hand sanitiser in the last few decades and no new developments are on the horizon either. It’s simple, Rogiers stresses. If your aim is to kill virus particles, your hand sanitiser only needs three ingredients. “Enough alcohol, water and bit of glycerin to protect your hands. Everything else is a luxury you don’t need and one that will do more damage than good.”

And one final tip: don’t leave your hand sanitiser or liquid in the car. Hand sanitiser can become flammable at high temperatures.

BIO – emeritus Prof. Dr Vera Rogiers

Rogiers for years led the In Vitro Toxicology and Dermato-Cosmetology department. She is a leading authority when it comes to the use of alternative methods as a substitute for lab animals in toxicology in dermato-cosmetic product applications.

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