Women have been given a stark warning about the permanent damage caused by brushing wet hair.
The common post-shower habit could be weakening your hair structure at a molecular level, potentially leading to increased breakage and thinning over time.
Many people underestimate the long-term consequences of this routine practice, according to co-founder and hair transplant surgeon at Smile Hair Clinic, Dr Mehmet Erdogan.
He said: "When hair gets wet, it undergoes significant physical changes that can affect its ability to handle stress from brushing."
The doctor warned against brushing your hair when wet
GETTYThe water causes the hair shaft to swell, stretching the cuticle and making it more susceptible to breakage.
Hair researchers have found that wet hair can stretch more than dry hair before breaking, but this apparent elasticity is misleading.
The expert added: "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. 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 said.
The protection of the hair cuticle continues to decline as a result of aggressive brushing on wet hair.
Fine hair and chemically treated hair are especially susceptible to this damage. This includes coloured, permed or relaxed hair, as their protein structure is already altered.
Once the protein structure of hair is broken down, it cannot be repaired; only cut off. Dr Erdogan recommended using wide-tooth combs instead of brushes for wet hair.
He warned: "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."
The American Academy of Dermatology also advises against brushing wet hair. Styling techniques that combine wetness and heat multiply the damage, according to Dr Erdogan.
The pro said: "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."
A study in the Journal of Cosmetic Science confirmed that wet hair subjected to heat styling suffered more structural damage than dry hair.
LATEST DEVELOPMENTS
"Never" brush wet hair from the root to ends
GETTYResearch from the University of Manchester shows that moisture changes hair's response to stress, with wet hair showing greater structural damage under thermal treatment.
Dr Erdogan advised: "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.
"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."
