Despite knowing the damage straighteners can do to our hair, many of us still happily run hot irons through our locks.
But a Californian hair guru has revealed another reason you may want to ease up on the sleek look.
In a video posted to Instagram, Guy Tang shows what happens to dyed hair as soon as a straightener is applied.
In Tang's video, he holds a piece of hair coloured in purple, blue, black and medium brown strips. The pigments fade dramatically after seconds of contact with the straightener.
Tang says it's the high heat of straighteners that's to blame. "Turn down the temperature," he warns.
He also advises that using a hot hair dryer or washing your hair in hot water can harm colour as well.
The video, which was posted on Instagram a week ago, has been liked over 34,000 times.
Tang, who has 1.2 million followers on the social media platform, describes himself as an ombre and balayage expert.
He also posts hair tutorials to YouTube, creating dramatic styles in bold hues including silver, hot pink and multi-coloured "unicorn hair".
Trichologists have previously warned against the damage straighteners can do to hair.
Consultant Trichologist Iain Sallis (hairmedic.co.uk) explained to the Daily Mail: "I regularly see women panicking because their hair has apparently started to fall out. But in fact, their hair is just breaking off due to their straightener addiction."
While hair is considered reasonably tough, he warns that any heat over 180c will damage the cuticle of the hair. With many devices reaching over 220c, this is way beyond what hair can withstand.
Before you think your hair is safe because you use a heat protection product, Sallis says those products are "a trap".
"Heat defence sprays are not a magic potion. They do reduce the damage, but the hair will still be affected if you use straighteners every day."