IT has transformed hundreds of Irish women from frizzy geek to straight chic.
But a treatment which tames fuzzy hair into a shining, sleek mass has now been relegated to the dustbin by the medicine watchdog.
The Irish Medicines Board (IMB) yesterday confirmed 'Acai Professional Smoothing Solution', a product within the 'Brazilian Blowout' range, has been banned in Ireland.
The professional salon-only treatment has been taken off the shelves after it emerged it contains high levels of a substance which can lead to serious health consequences.
And hair stylists who use the treatment, which is manufactured in California, have been told to immediately stop -- due to the presence of unacceptable levels of the chemical formaldehyde, well-known for its use in preserving human remains.
Its makers said the product smoothed and conditioned the hair by creating a "protective protein layer" around the hair shaft to "reconstruct and strengthen" while eliminating frizz.
The end result was smooth, healthy, conditioned hair with radiant shine, the makers added, and the product was available in hairdressing salons throughout Ireland.
However, it has been found to contain formaldehyde levels in excess of that permitted for inclusion in cosmetic products under European and national legislation. Testing revealed the treatment contained levels of formaldehyde above the permitted amount of 0.2pc when used as a preservative.
The IMB yesterday confirmed it had not received reports to indicate a significant incidence of undesirable effects in relation to the product.
However, formaldehyde is a known irritant and it is feared that inhalation over a long period of time could lead to more serious health consequences.
The greatest risk of exposure is when the substance is being applied to hair.
During this time the hair will be heated as the stylist blows dry and then straightens the hair using straightening irons, which may cause the formaldehyde to vaporise.
Stylists and people to whom it is being applied may endure irritation of the eyes, nose and throat, as well as breathing difficulties.
The Irish Hairdressers' Federation said last night it was aware that a number of products, commonly known as 12-week blow-drys, had been recalled for further testing.
It advised its members to contact the supplier or manufacturer of the product they are using immediately for an update on its status.
"The IMB can confirm that the distribution of 'Acai Professional Smoothing Solution', a product within the 'Brazilian Blowout' range has ceased," a spokeswoman for the IMB said.