As the novel coronavirus spreads around the world, so is a lot of misinformation about how people can protect themselves. Predictably, the pandemic has energized brands and influencers hawking nutritional supplements and other products that they claim can give immune systems a quick and easy “boost” to ward off this coronavirus and the resulting disease, COVID-19.

Such marketing often exasperates immunologists, who stress that it’s not really possible to boost otherwise healthy immune systems, explains Sheena Cruickshank, an immunologist at the UK’s University of Manchester. Nor is that something you’d want, even if it were a possibility: when people develop severe forms of COVID-19, many experts believe it’s because their immune systems are spiraling into overdrive and overwhelming their bodies.

We just need the nuts and bolts of our immune machinery to work normally. People should strive to have a healthy baseline, says Lisa Gralinksi, a virologist who studies coronaviruses at the University of North Carolina at Chapel Hill. “If they do unfortunately get infected, they’ll be in the best possible situation to fight off this infection and stay healthy,” she says. Thankfully, there are some solid, science-backed ways to do that.