Women love them and hairdressers swear by them, but dermatologists warn the obsession with hair straightening irons is ruining tresses everywhere.
A meeting of international hair and skin specialists in Chicago has been told the trend towards daily use of hair-styling flat irons is causing "massive damage" to hair through strand burns and breaks.
Dermatologists warned the problem was with newer, ceramic-coated tongs that, ironically, were designed to protect hair by getting hotter and straightening faster than the traditional metal irons.
"It is really a classic case of buyer beware," one professor told the meeting.
"We're seeing that when these ceramic flat irons are used at the highest heat settings and on a daily basis to achieve straight hair they can really take a toll on the structure of the hair and cause very noticeable problems that can be hard to repair."
Sydney dermatologist Dr Phillip Artemi said the problem was becoming increasingly prevalent in Australia, with more women presenting at clinics with severe hair damage.
"If you look at the sales statistics you see that people are pursuing straighter hair with more vigour," Artemi said.
"Most people on TV and in films have straight hair and it's a trend the public is trying to emulate.
"The problem starts when they do it wrong or too frequently and they cause a real mess that takes a long time to fix."
He said the tongs damage the outer part of the hair fibre, leading to a "dry, weathered look" with strands that split and snap off easily.
Patients with major hair damage from tongs are told to keep their hair short for one to two years, stop use of tongs, hair dryers and heat products altogether and avoid sun exposure.
But to avoid damage in the first place, only use the equipment on dry hair, never more then twice a week and at temperatures under 170 degrees celsius, Artemi said.
"If you want to join the trend, fine, but do it with common sense or you could wind up with massive damage," he said.
