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.
Who: Maria Del Russo, features editor
Where: The bathroom
Typically, Maria keeps her brushes on a shelf in her bathroom, above the toilet. And therein lies the problem: "When you flush your toilet, you're aerosolizing microorganisms, and there's a possibility that every time the toilet is flushed, microorganisms from the bowl can land on surfaces," says Megan Rutland, team lead of cosmetics testing at Microchem Laboratory. "They could've landed on the makeup brush, in Maria's instance."
And land they did. Maria's brush — which also traveled to Paris with her for a weekend and hung out in the bathroom there — turned out to be teeming with little buggies. In Wilson's words, "Maria had a nasty little brush."
The count of yeast and mold was relatively neutral, but for aerobic bacteria, the number was "TNTC" — or too numerous to count.
Luckily, Maria's brush wasn't growing any particularly dangerous bacteria, like staphylococcus aureus or coliform. "Not all bacteria is harmful, but there needs to be a balance, and you could throw off the balance of the skin which would lead to negative effects [and potential infection]," Wilson says.
Who: Patricia Beam, executive production associate
Where: The subway
It wasn't hard to find someone who does her makeup on the subway. And Patricia? Well, she's a pro. "I literally do all my makeup — foundation, brows, liquid liner — every day on the subway on my way to work," she says.
While Patricia usually washes her brushes once a week, we had her stake it out for two full weeks — and the lab results were not pretty. Her foundation brush had near-dangerous levels of yeast, mold, and aerobic bacteria. But even scarier? It also had a splash of coliform — yep, the fecal one — which shouldn't be present at all.
"What this tells me is to not do makeup on the train," Wilson says. "Just don't do it. With these very high levels, there's no way you can avoid throwing off the balance of your skin, and your skin could become sensitive and dry, leading to breakouts, redness, and blotchy skin."
And the issue gets worse depending on the kind of makeup you use. Patricia's foundation was waterless, meaning it likely didn't add to bacteria growth. But, "if she had used a water-heavy foundation, it would've picked up much more," Wilson says.
Sure enough, Patricia noticed a breakout on her chin in the final days of the experiment. Convinced yet? Let's move along.
Who: Danielle DeJoy, growth strategist
Where: The medicine cabinet
Even though Danielle applied her makeup in the bathroom like Maria, her brush was the cleanest by far, with barely traceable levels of bacteria. The main difference? It was left in an enclosed space, which likely stopped aerobic bacteria from landing on the brush every time the toilet flushed.
Who: Jessica Chou, digital innovation editor
Where: The makeup bag
We've written about just how gross your makeup bag is before — so we were admittedly nervous to get the results on this one back. Imagine our surprise then when the brush only had trace levels of aerobic bacteria, yeast and mold, and absolutely no staph or coliform. What?!
I mean, that little brush traveled. I brought it on airplanes, used it in public bathrooms, buffed my face with it in hotels...
So what gives? Pros say that keeping it in a closed container certainly helped. But so did the products I was using: my BB cream, blush, and sunscreen are all low in water content, and "that does make a difference because it leads to less room for the microbes to grow," Wilson says.
Who: Ally Hickson, associate digital innovation editor
Where: Her bedroom
We assumed Ally's brush would be the cleanest, since the bedroom seems like the least gross place to apply your makeup. (There's no swirling toilet, no strangers coughing and sneezing, and no steam wafting from the shower.)
And sure enough, it had totally normal yeast and mold levels and no staph or coliform. But the one big number? Aerobic bacteria, which was likely due to the fact that she left it out on her dresser instead of in an enclosed place like Danielle.
A little extra bacteria on your brushes isn't exactly hazardous and your skin will balance itself out, Wilson says, but it's still gross to think about. (And, left uncleaned, it could double in two weeks.)
So, again, moral of the story? Just clean your brushes, people.
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