SEATTLE—Shoppers had ransacked the shelves of isopropyl alcohol. Clorox bleach or Lysol disinfectant? Nothing at one store, and selling out fast fast at another. Hand sanitizers, Purell wipes, Wet Ones? All a distant memory.

But worried shoppers at stores across Seattle’s King County, the site of the vast majority of 2019 novel coronavirus deaths in the United States, haven’t emptied out what might be the most effective preventive tool in the game: hand soap.

Erin Sheets, a professor of chemistry and biochemistry at the University of Minnesota Duluth, told The Daily Beast that the exterior of the novel coronavirus that causes COVID-19 is coated in proteins and lipids, or fat-containing molecules. This lipid envelope provides a protective cover, while the embedded proteins help the virus attack our cells, enter them, and replicate, she said.

Research on other coronaviruses has shown that “lipids play crucial roles at various stages in the virus life cycle,” according to one recent study. They’re so important, in fact, that scientists are eying viral lipids as prime drug treatment targets.

Lipids are, in other words, the Achilles heel of coronaviruses, and soap provides an effective arrow. It is a detergent, which allows it to bridge the gap between water and grease or other fats, Sheets said. (Americans of a certain age may recall the “Dawn takes grease out of your way” tagline for the dishwashing detergent.) Hand soap does the same thing through brute force: it essentially dissolves the lipid envelope of the virus, thereby inactivating it.

Even better, Sheets noted , soap alters the outer viral proteins, or “denatures” them in a way that interferes with their normal jobs. “The lipids and proteins that are needed for that virus particle to enter the cell don’t exist anymore or they aren’t functional,” after washing, she explained .

A similar envelope-destroying process occurs with hand sanitizer that contains at least 60 percent alcohol, she continued . Experts say it’s a solid alternative when soap isn’t available. Alcohol also disrupts RNA molecules within the virus, which are essential for a viral particle to make copies of itself. For sanitizing surfaces like countertops and doorknobs, bleach-containing disinfectants also work (though bleach is too caustic to be used on your hands). “If you destroy the proteins and lipid membrane, it doesn’t matter how you’re doing it,” Sheets said.

Palli Thordarson, a chemist at the University of New South Wales in Sydney, recently posted an even more in-depth, multi-part primer on soap and viral biochemistry that went viral on Twitter.

Along with the advice, other viral memes have suggested that people sing the “Happy Birthday” song or even recite lines from “Dune” or “Macbeth” to ensure that they wash their hands for a full 20 seconds. That advice may be particularly important for men, who have been historically bad at practicing good hand hygiene after using the bathroom.

But why 20 seconds? Hands are rougher surfaces than, say, metal or glass, meaning that we need to work a little harder to ensure that soap suds can latch onto any viral particles, dissolve their envelopes, and inactivate them. “It gives you time to get into the webs of your fingers and the backs of your hands,” Sheets said.

Just be sure that any hand cleansers include ingredients, like the fats and oils in soap, that can specifically disrupt the coronavirus lipid envelope. “Stick with what’s tried and true: soap and water, hand sanitizer, bleach if it’s a surface,” Sheets said. “Why go exotic? This is not the time to mess around.”