We Sent Our Makeup Brushes To A Lab — & Immediately Regretted It

There are two types of makeup users in the world: those who meticulously wash their brushes every Sunday. And those who... don't.

And, look, we get the process is time-consuming. (Many of our beauty editors admit to slacking off themselves.) But here's the thing: Every time you use your makeup brush, "you spread dirt and bacteria and even viral particles from your face to your makeup, then back to your face, and [you] accumulate dead skin cells, dirt, oil, and bacteria on your brush," dermatologist Dr. Fran E. Cook-Bolden, MD, tells Refinery29.

Once those levels of bacteria get too high, dirty makeup brushes can lead to breakouts, irritation, and even infection if used over damaged skin (a popped zit, a scratch, etc.). To avoid that, Cook-Bolden recommends washing them at least once a week, and even more so if you can. "[Try] pairing it with another weekly activity so it becomes a habit," she says. And, it's also important to be mindful of where and how you store them. "If someone took a damp brush and threw it in a drawer, it’s the perfect place for microbials [to grow] because it’s dark and warm," says Ni'Kita Wilson, cosmetic chemist and CEO of Skinects.

But the ultimate kick-in-the-pants for us? A little healthy, fear-based exercise. Which is why we decided to send our brushes to a lab to see just how dirty they really were. We tasked five editors to use the same, brand-new foundation brush regularly in five different places: the bathroom, the bedroom, the subway, and more. After two weeks, we sent them to Microchem Laboratory to be tested for aerobic bacteria, yeast, mold, coliform (the bacteria associated with the presence of feces, sorry), and staphylococcus aureus.

It's important to remember that most brushes have a normal level of bacteria on them — as do our bodies and everything we touch. It's when those levels get too high that it's a problem, which is exactly what happened to some of our editors. Check out the results ahead, and get your brush cleaner ready.