For those with a hair care routine, a brush is an essential tool for daily upkeep — but brushing hair while it’s wet could cause more harm than good.

The common habit could permanently weaken hair at a “molecular level,” according to Dr. Mehmet Erdogan, co-founder and hair transplant surgeon at Smile Hair Clinic in Istanbul.

This could lead to increased breakage and thinning over time. A 2022 study from the University of Manchester reflected this, finding that moisture can change hair’s response to stress.

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“When hair gets wet, it undergoes significant physical changes that can affect its ability to handle stress from brushing,” Erdogan said in comments shared with Fox News Digital. 

“The water causes the hair shaft to swell, stretches the cuticle and makes it more susceptible to breakage.”

Although research has shown that wet hair stretches more than dry hair before breaking, Erdogan clarified that this doesn’t mean the hair is more flexible and resilient.

“The opposite is true – this stretching damages the internal protein structure, leading to weaker hair over time,” he warned.

“Wet hair is more fragile, and rough brushing can cause breakage.”

“The brush pulls on swollen, weakened strands, causing them to stretch beyond their capacity. As they dry, they don’t return to their original state and remain damaged at a structural level.”

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Ashley DiMatteo, owner of Ashley Lauren Beauty Lounge in Westchester, New York, told Fox News Digital in an interview that the salon has “definitely seen” damage from brushing wet hair.

“Wet hair is more fragile, and rough brushing can cause breakage,” she said. “But it’s rarely just one issue – hair loss or damage often comes from a combination of factors like stress, hormones, heat styling or chemical treatments.”

Brianna Delvecchio, a color specialist and hairdresser at DiMatteo’s salon, agreed that brushing wet hair can cause breakage, especially while doing so roughly or with the wrong tool.

Factors like stress, diet, hormones and overprocessing can also play a role in hair damage, she confirmed.

Those who have fine and chemically treated hair – whether colored, permed or relaxed – are “especially susceptible” to wet brushing damage, since their protein structure is “already altered,” Erdogan noted.

Tips to minimize hair damage

The risks don’t mean people should skip brushing altogether, Delvecchio said, as not brushing wet hair can sometimes result in a “knotted, matted mess.”

“Brushing is necessary — just do it gently and in the right way,” she advised.

With her salon clients, DiMatteo recommends taking a “gentle approach” to hair, protecting it from heat, avoiding rough brushing and limiting chemical services.

“We also take time to talk about scalp health, nutrition and lifestyle, because those all play a role,” she told Fox News Digital. “And most importantly, don’t ever feel embarrassed or shy to speak to your stylist or local salon. We’re here to help.”

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To lower the risk of hair damage, experts recommend using a wide-tooth comb or flexible detangling brush.

“The flexible bristles are great for detangling without too much tension,” Delvecchio said. “It’s a solid option for all hair types, as long as you’re still gentle and patient.”

The salon owner also suggested using a leave-in product to help soften and hydrate the hair, making it “much easier for the comb to glide through.”

“Technique matters, too – always start from the bottom and gently work your way up,” DiMatteo advised.

Adding heat to wet hair can “multiply the damage,” Erdogan warned.

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For those with straight hair, it’s best to allow it to partially air-dry before combing, according to the hair transplant surgeon.

The American Academy of Dermatology Association also recommends this approach.

Delvecchio advised going “easy on your hair” overall, especially when it’s wet.

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“Use heat protectant, lower the heat on your tools, avoid overlapping bleach and keep up with trims,” she suggested.

“Also, brush regularly (wet or dry) to prevent tangles and breakage,” she went on. “Hair is delicate, but with the right habits, it can stay strong and healthy.”