As a cosmetic chemist, a big part of my job is making sure we make safe products.
In order to make safe products I've developed a particular set of skills. Skills acquired over a long career. I find harmful microbes, and I kill them. Endlessly, you might even say gleefully, and with the utmost attention to detail, and the relevant science.
COVID-19 corona virus is spreading, and will likely reach pandemic levels soon. Health officials are urging people to practice good "hand hygene" by washing your hands frequently with soap and water, or using a hand sanitizer to help limit the spread of the disease. There seems to be a shortage of hand sanitizers, cleaning products, and disinfectants in a lot of places so people are starting to improvise.
Last night on Facebook I saw an article from a usually reputable source that gave a recipe for an all-natural DIY hand sanitizer using vodka. The CDC recommends that any hand sanitizer needs to be at least 60% alcohol to be effective. Regular vodka is only 40% alcohol. It will not fully sanitize anything. I spoke up immediately, as did a lot of other people. The post has been pulled, but unfortunately the article was shared thousands of times. I’ve seen ineffective recipes in countless places, and it’s dangerous.
60% is the minimum amount of alcohol required in hand sanitizers, and you’d think the more the merrier, and be tempted to use the 91% rubbing alcohol, but it’s not as effective. Sanitizers rely on contact time in order to be effective, and they need a little bit of water to help denature the proteins, penetrate the membranes of whatever you’re trying to kill, and it increases the contact time because it dries slower. The sanitizing “sweet spot” is a product containing 60-70% alcohol.
There are a few different kinds of alcohol, but in the DIY hand sanitizer realm there are really two that count: ethanol- the kind that you can drink, and isopropyl alcohol- a.k.a. Rubbing alcohol (the kind you can only drink once). They’re interchangeable in DIY hand sanitizer recipes, but I think ethanol is a little nicer to your skin, and safer if you have small kids that could potentially ingest it. It is, however, much more costly, and high proof vodka may not be available where you live. Regular old isopropyl rubbing alcohol from the drug or discount store will work just fine.
With all that in mind I came up with a few recipes based on what I could find here in my very tiny town with limited shopping options. Each one is formulated to give you a final alcohol concentration of at least 60%. If you’re using water to dilute the alcohol make sure it’s very clean so you don’t contaminate your sanitizer. Distilled water is pretty easy to find in the US, and is about $1 a gallon.
½ cup (120 ml) 70% isopropyl alcohol or 151 proof vodka
1 Tablespoon (15 ml) aloe vera gel OR distilled water
6 Tablespoons(98 ml) 91% isopropyl rubbing alcohol or 180 proof vodka
2 Tablespoons (30 ml) aloe vera gel or distilled water
You can add a few drops of essential oil to make it smell nice, but it’s really mainly just for scent. I can’t find a single good scholarly article about using essential oils to kill the corona virus. I know there are a lot that have great anti-microbial properties, but without good research I can’t in good conscience recommend them to fight the corona virus.
Thanks for reading this! Please share this as widely as you can to keep everyone safe, and from wasting their time on ineffective recipes. Stay healthy!