A hair transplant surgeon has revealed why brushing wet hair may cause more permanent damage to hair follicles than many people realise.
Dr. Mehmet Erdogan, Co-Founder and Hair Transplant Surgeon at Smile Hair Clinic, explains this common post-shower habit weakens hair structure at a molecular level, potentially leading to increased breakage and thinning over time.
“When hair gets wet, it undergoes significant physical changes that can affect its ability to handle stress from brushing. The water causes the hair shaft to swell, stretches the cuticle and makes it more susceptible to breakage,” said Dr. Erdogan.
Hair researchers have found that wet hair can stretch more than dry hair before breaking, but this apparent elasticity is misleading.
“Many people think because wet hair stretches, it must be more flexible and resilient. The opposite is true – this stretching damages the internal protein structure, leading to weaker hair over time,” he explained.
Hair breakage is a common issue because of improper wet hair care. “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,” Dr. Erdogan noted.
Wide-tooth combs should be used instead of brushes, for wet hair. “If you must detangle wet hair, use a wide-tooth comb starting from the ends and working your way up. Never start brushing from the roots when hair is wet,” he said.
According to the surgeon, styling techniques that combine wetness and heat multiply the damage. “Using a hairdryer on soaking wet hair is particularly harmful. The fast evaporation of water from within the hair shaft creates a mini explosion effect, pushing out and damaging the cuticle from within.”
“For people with straight hair, letting your hair partially air dry before gentle combing is the ideal way to do it. For curly or textured hair, use a conditioner and wide-tooth comb while still damp,” he advised.
The protection of the hair cuticle continues its decline as a result of aggressive brushing on wet hair. Fine hair and chemically treated hair – whether colored, permed or relaxed – are especially susceptible to wet brushing damage because their protein structure is already altered.
A study published in the Journal of Cosmetic Science found that the rapid evaporation of water from hair due to heat is a main causal factor in heat-related hair damage. The study shows that wet hair subjected to heat styling suffered more structural damage than dry hair under the same conditions.
Research from the University of Manchester shows that moisture can change hair’s response to stress. The research concluded that wet hair shows greater structural damage under thermal treatment, with decreases in elasticity and strength not seen to the same degree in dry hair.
The rise in heat styling tools and substances used to manage modern hairstyles has created new challenges for hair integrity, says the hair surgeon from Smile Hair Clinic.
The American Academy of Dermatology also advises against brushing wet hair, and recommends that people with straight hair should let their hair dry partially before gently combing with a wide-tooth comb, while those with textured hair should only comb when hair is damp.
Dr. Erdogan summarized that prevention and using the right drying and styling technique remains the most effective approach when it comes to hair damage. “Once the protein structure of hair is broken down, it cannot be repaired – only cut off. Applying the right hair care when wet is the best way to maintain healthy hair long-term and to prevent unnecessary thinning caused by breakage.”
