Hand hygiene is an important part of the fight against COVID-19, but homebrew hand sanitisers can do more harm than good.

Since the outbreak of COVID-19, more people are buying hand sanitisers than ever before. As one of the most sought after panic buy products, most shops and pharmacies are selling out as soon as they get a chance to restock. The result of this, however, has been a trend of people making homemade hand sanitisers with limited knowledge of what works against the virus or how to produce safe hand hygiene products.

How do hand sanitisers vary?
Broadly, there are two types of sanitisers to be aware of: alcohol-based and alcohol-free. Industry-standard alcohol-free sanitisers contain substitute chemicals that are just as effective in eliminating all microbes, including Coronavirus. The effectiveness of hand sanitisers will, however, vary dependent on the ratio and strength of their chemicals so this should be considered when making a purchase.

Are all alcohol-based hand sanitisers the same?
Alcohol is present within hand sanitisers in two forms that should be looked out for: Isopropanol Alcohol (IPA) and Denatured Ethanol (DE). Both of these types of alcohol are able to protect against the virus. There will also usually be a percentage found on any hand sanitisers, however, that is important. This percentage tells you the volume of alcohol present within the hand sanitiser. According to the CDC’s Hand Hygiene Recommendations, sanitisers should have contain more than 60% ethanol or 70% isopropanol to protect effectively against the virus.

While it may feel intuitive to go for as high an alcohol volume as possible, those that are very high in alcohol content can actually be ineffective. This is because, the higher the alcohol content in sanitisers, the quicker they evaporate when applied to skin.

Why not make my own hand sanitiser?
While self-isolation can inspire people’s DIY spirit, it is important to remember that there is a reason why hand sanitiser companies exist in the first place. From damaging or cracking skin after use (making them more susceptible to infection), to cross-contamination, making your own can hand sanitiser can cause more problems than it solves. IPA and DE also present a significant safety risk when handled outside a controlled environment, being highly flammable substances.

There is also the risk that popular homemade sanitiser recipes are actually not going to protect against the virus. One such recipe, popularised here on the Verge, requires 91 percent rubbing alcohol and one part aloe vera gel. This recipe should produce something with theoretically 60.6% alcohol content. According to CDC guidelines, however, an IPA-based hand sanitiser should contain at least 70% to be effective against COVID-19.

Keeping hands sanitised
Local newsagents along with online cleaning product suppliers that are still stocking hand sanitisers, such as Cleanroom Supplies, can both be effective alternatives to making regular trips to the supermarket. While in the home, it is also important to remember that soap and warm water are effective for protecting against COVID-19, meaning that you can save your hand sanitiser for whenever you need to make a journey. As the CDC highlight in their hand sanitiser factsheet, however, you must make sure that your hands are clean and washed before using any hand sanitiser.