How Bad Is It Really to Never Wash Your Hair and Makeup Brushes?

You've probably heard the advice to wash your hair and makeup brushes regularly. But let's be honest: How many of us are actually taking the time to do so?

Well, according to a May 2015 Harris poll, 22 percent of people who use makeup brushes never clean them and 39 percent soap them up less than once a month.

The truth is, if you don't give your brushes a bath, you're putting the health of your skin, scalp and hair on the line. (Heads up: This might be why you're losing hair or breaking out.)

Here, we untangle what can go wrong when your brush turns into a dirt bomb.

"Makeup brushes are meant to be as clean and sterile as possible because we transfer whatever is on the brush onto our faces," says Corey L. Hartman, MD, founder and medical director of Skin Wellness Dermatology in Birmingham, Alabama, and assistant clinical professor of dermatology at the University of Alabama School of Medicine. "An unwashed brush accumulates dirt, dust particles, dead skin cells, excess oil from your skin and makeup residue."

When you spread all this stuff from your brush onto your face, it might clog your pores, which are little pockets in your skin that secrete sweat or oil. "Clogged pores can lead to breakouts," Dr. Hartman says.

And that's not all. Once you've got debris sitting on your brush, you're basically inviting in bacteria.

"Bacteria sets in easier than people realize, particularly if you store your makeup brushes in a moist environment like your bathroom," Dr. Hartman says. "Your pores provide a portal of entry for these unwanted organisms to take hold."

Now, your skin already hosts a thriving microbiome of good bacteria — some of which actually fight pimples, according to a September 2020 study in the ​Journal of Clinical Dermatology​. But introducing bad bacteria is another story altogether.

"These invaders trigger an inflammatory process," Dr. Hartman says. "It results in flareups of acne or folliculitis, which is the formation of pustules around your hair follicles caused by a bacterial infection."

Dusting your complexion with a dirty brush also opens the door to infection — especially if you have a micro-abrasion, which is a tiny scratch on your face that you might get from, say, using a harsh exfoliator, having cracked lips, waxing or derma-planing.

Exhibit A: "Impetigo occurs when a staph infection permeates the surface of the skin, which then erupts in blisters," Dr. Hartman says. According to the American Academy of Dermatology (AAD), there's also a chance you could get a fungal infection.

It's especially critical to wash eye makeup brushes on a regular basis. "Your eye is a direct route to your brain," Dr. Hartman says. "You could potentially get a serious systemic infection if you use a dirty brush close to the eye."

While we're at it, here's your reminder to never share makeup brushes. The risks are rare but real: As reported by the ​Daily Mail​, a 27-year-old Australian woman was paralyzed when she contracted MRSA, an antibiotic-resistant staph infection, from using a friend's makeup brush.

Model Anthea Page also reportedly got a staph infection in her eye when a makeup artist forgot to clean her brushes. Herpes, strep and conjunctivitis can also be spread by passing around beauty tools.

"Your eye is a direct route to your brain. You could potentially get a serious systemic infection if you use a dirty brush close to the eye."

Grime gloms onto the fine, porous bristles of your makeup brushes, and eventually starts to break them down.

"As a result, they won't be able to hang onto makeup effectively and you won't have a smooth application," Dr. Hartman says.

Your makeup will come out blotchy and clumpy instead of gliding on easily — which goes against the whole point of it.

When you slide a brush through your hair, anything that's lingering in your strands will coat the bristles of your hairbrush. Think: hair product residue, grease, sweat, flakes of dead skin from your scalp, soot and dust. Every time you brush, this petri dish of grossness is transferred back onto your mane.

"It's similar to what happens with a makeup brush, but you have the added factor of hair snarled in the brush, which acts as another nidus of potential problems," Dr. Hartman says, noting that we lose between 25 and 100 hairs a day. "The waxy buildup on the bristles and stuck hair makes your hair and scalp more oily, which can set off an overgrowth of a naturally occurring yeast."

This yeast, called Malassezia, feeds on oil — so the greasier your mane is, the more it multiplies. And when Malassezia gets out of control, you can say hello to flakes.

"The yeast can contribute to seborrheic dermatitis, or dandruff, an inflammatory condition resulting in an oily, itchy, scaly rash on the scalp," Dr. Hartman says. "What's more, if your hair texture makes it difficult to shampoo on a daily basis, you are at a higher risk of seborrheic dermatitis to start with since your scalp tends to be oilier."

As a result, you need to be extra vigilant about hairbrush hygiene.

Scary, but true.

Here's how it happens: "Seborrheic dermatitis is often itchy, and scratching your scalp can cause your hair to break," Dr. Hartman says. "Plus, an inflamed scalp can't produce normal hair."

Dragging your fingernails across your head can also lead to scarring.

A May 2019 ​PLOS One​ study suggests that Malassezia is associated with hair loss, and according to the University of Central Florida College of Medicine, scratching can also damage hair follicles, obstructing hair growth and leading to shedding.

The good news: Thinning hair is usually temporary. Once you resolve the seborrheic dermatitis, your strands should grow back.

"Not only are you risking harm to your scalp and hair if you don't clean your hairbrush, but it will impair the brush's function," Dr. Hartman says, pointing out that bristles perform at their peak when they are clean. "If the bristles are covered in residue, they will become weak and start to snap off or fall out."

That's a problem for your look because brushing with craggy, beat-up bristles can lead to hair breakage, Dr. Hartman says. Plus, pulling a gunked-up brush through your mane applies friction against the hair shaft. Instead of brushing your hair cuticles into a smooth, glossy finish, the jagged bristles will rough them up, creating coarse, frizzy strands.

We know it's a pain, but sanitizing your brushes can ward off a slew of hairy situations.

The AAD urges people to suds up their makeup brushes every seven to 10 days and change them out after three to six months. "The time span depends on the thickness and composition of the makeup you're applying," Dr. Hartman says. For example, a foundation applicator may need to be washed more frequently than a bronzer brush.

The amount of makeup you put on also plays a role. "If you only wear light makeup a couple of times a week, you may be able to wash your brushes once every two weeks," Dr. Hartman says. "Whereas someone who uses heavy makeup on a daily basis should wash them weekly."

Finally, people with oily skin should stick to once-a-week cleans. "You will tend to have more issues because of the oil buildup," Dr. Hartman says.

And always dispose of makeup sponges after a single use because they soak in microbes. An October 2019 study in the ​Journal of Applied Microbiology​ analyzed the microbial contamination of beauty products and found that beauty blenders had the highest degree of contamination, including fungus and bacteria like staph and E.coli. The study also found that 93 percent of beauty blenders had never been cleaned, despite the fact that 64 percent of them had been dropped on the floor. Yuck!

The guidelines are similar to makeup brushes.

"Clean your hairbrush once a week if you use a lot of product, have a scalp issue like dandruff or don't wash your hair frequently," Dr. Hartman says. "Otherwise, once or twice a month should be fine — but still, you should remove hair that's stuck in the brush weekly."

Time to brush up on your cleansing technique!

1. ​Lather​ up a fragrance-free baby shampoo or gentle cleanser in your hands, and then massage it through the bristles.
2. ​Rinse​ with warm water until it runs clear (this is important, because soap residue could irritate your skin).
3. "​Dry​ the brushes with the bristles pointed down, to allow water to drip off and evaporate," Dr. Hartman says. If moisture accumulates between the bristles, it can lead to mold spores. You can buy an inexpensive makeup brush drying rack, or just lean them against something so the bristles hang down.

As for spray cleaners, which promise to clean and disinfect makeup brushes in seconds? Dr. Hartman's not a fan. "Introducing a new chemical can be problematic, and a spray won't give you a thorough clean," he says. "Although it might let you extend the period of time between washings, it's not a good substitute for actually cleansing the bristles themselves."

1. ​Remove​ any trapped hair. "Get in between the bristles and lift the hair out using a pointed tool like a rattail comb," Dr. Hartman says.
2. ​Lather:​ Next, fill a bowl with warm, soapy water (use mild shampoo for the soap). If you have a plastic brush, submerge it fully; if your brush is wooden, dip in just the paddle portion of the brush so that you won't damage the wood. "Let it sit there for a few minutes, moving it around in the water to help loosen up the oil," Dr. Hartman says. "If necessary, scrub the base with a toothbrush to get off the grime."
3. ​Rinse:​ Fill the bowl with clean water and swish the brush around inside.
4. ​Dry:​ Let it rest on a clean towel, bristles facing down.

A regular brush cleanse really is something you should squeeze into your schedule. "Using dirty brushes can be more detrimental than you think," Dr. Hartman. "You are risking real damage to your scalp, hair and skin."

Is that still true if you don't have any existing issues? "In this case, prevention is worth a pound of cure," Dr. Hartman says. "You want to avoid these things ​before​ they become a problem."