Recipes for homemade hand sanitizer concoctions have been multiplying online but experts are warning that many of the DIY solutions are ineffective — even harmful.

"You don't want anyone making up their homemade hand sanitizers that might have a component that's going to lead to some kind of toxic reaction on their hands," said Dr. Alyson Kelvin, an assistant professor at Dalhousie University in Halifax and a member of the Canadian Centre for Vaccinology.

"We don't need any more people in the hospitals right now."

Shortages of hand sanitizer have prompted some Canadian distilleries to make their own. (CBC/Sophia Harris)

Commercial hand sanitizing liquid has been hard to find in recent weeks as news of the spread of the COVID-19 virus has prompted Canadians to empty store shelves.

Health Canada — which considers alcohol-based hand sanitizers to be natural health products — authorizes the products that can be sold in Canada and assigns each one an eight-digit Natural Product Number, displayed on the product's label.

But faced with the shortage of hand sanitizing solutions and other equipment needed to fight the COVID-19 virus, such as masks, gowns and swabs, Health Canada decided earlier this month to temporarily allow for sale some products that don't meet some requirements, such as licensing and bilingual labelling.

"The department is allowing certain products to be sold in Canada that may not fully meet all requirements under this interim measure," the department said in a statement, pointing out that it is maintaining a list on its website of products given temporary approval.

Dr. Alyson Kelvin is an assistant professor at Dalhousie University's Department of Microbiology and Immunology. (Craig Paisley/CBC)

To date, 14 hand sanitizers or disinfecting wipes have been given temporary authorization. Some of them are imported.

The list doesn't currently include the many distilleries and breweries across the country that have announced plans to turn their skills to producing hand sanitizer.

Many Canadians are turning to social media for information about how to make their own — and some of that information is very misleading.

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One YouTube video that touts a concoction of witch hazel, tea tree oil and aloe vera has been viewed 1.8 million times. Another YouTube video, viewed 747,000 times in the past two weeks, recommends isopropyl rubbing alcohol with concentrations as low as 70 per cent — a level that, when mixed with the other ingredients, wouldn't be enough to kill the virus.

Posts on sites like Facebook and Reddit have advised using things like vodka and tea tree oil to make your own hand sanitizer.

Many homemade remedies don't work

The World Health Organization's website has legitimate instructions for making hand sanitizer that recommend using ethanol with a concentration of 96 per cent, or isopropyl alcohol with a 99.8 per cent concentration.

Experts say the best way to kill the COVID 19 virus on your hands is to wash them properly with soap and water. If that's not an option, an effective hand sanitizer should have an alcohol concentration of at least 60 per cent.

Kelvin said one of the people who saw recipes for homemade sanitizer on the internet was her own daughter.

"My 10 year old daughter saw online that she could make it herself. It's a little bit alarming that even children are seeing this."

Kelvin said hand-washing is the best approach because dirt or grease on your hands can interfere with hand sanitizers. She said it takes at least 20 seconds for properly made hand sanitizers to de-activate the virus.

While manufacturers can standardize the quality of their products and test individual lots, that's harder to do with homemade solutions, she said.

"There's no guarantee when you make it that it's actually 60 per cent."

Vodka isn't strong enough

Kelvin said she hasn't seen any studies on tea tree oil or witch hazel being able to render viruses like COVID-19 inactive. And vodka isn't strong enough, she said.

"That's probably not at 60 per cent, or our livers wouldn't be doing very well."

Even the recipes that call for highly concentrated alcohol could cause problems, Kelvin said.

"Most of the recipes are alcohol-based and that could create skin problems or be toxic to your own hands, so you have to watch out for that when looking at homemade recipes."

Ada McVean, a science communicator with McGill University's Office for Science and Society, said there are a lot of recipes out there.

"My great grandmother was actually texting me the other day, asking me to look at her formulation for homemade hand sanitizer," said McVean. "And when I ran the math on what percentage her formulation was coming out at, it was incredibly too low."

Another potential hazard: the 99 per cent alcohol needed to make sanitizer can be very flammable, while some other ingredients could cause allergic reactions.

"If you have never used tea tree oil or lavender essential oils, or any other oils or perfumes, or whatever they're having you add to cover up the smell, there's a huge risk of allergic reaction," said McVean.

"As well, if you're just using alcohol and not adding anything like aloe vera ... you could dry out your skin to the point that it starts cracking, even on the microscopic level," she said, adding that the novel coronavirus could hide in those cracks.

That's why, in the end, hand-washing is better than hand sanitizer, McVean said.

Elizabeth Thompson can be reached at elizabeth.thompson@cbc.ca

CBC's COVID-Check unit is here to help you sift through the noise and get to the truth. If there is something you want us to check out and verify, contact us at covidcheck@cbc.ca