At least 15 beauty salons have been using counterfeit Thermage machines - the genuine ones are meant for use only by doctors - to remove wrinkles and to smooth the skin of their clients.
The machines are used in aesthetic treatment to tighten and contour the skin on both face and body, deal with wrinkles and smooth out cellulite.
They are also used to alleviate muscle spasms and, in surgery, to help with wound healing.
The original machines, called the Thermage CPT System, cost over $80,000 but the counterfeits are available for between $18,000 and $38,000. The original is made by US medical device company Solta Medical, a subsidiary of Valeant Pharmaceuticals.
Solta representatives, together with the police, raided local company I Health International's showroom in Woodlands Road in June.
They seized two fake machines carrying its trademark, but which were made in China.
Solta said it does not make any of its machines in China.
The raid also uncovered documentation at the showroom, showing that at least 18 such fakes were sold by I Health International to 15 beauty salons here and one in Johor.
The raid followed a tip-off from a member of the public.
Ms Grace Guang, head of Solta's legal and compliance department for the Asia-Pacific, said the fakes look pretty much like the real ones except that their tips are not detachable.
These tips are meant for one-time use and carry a thin membrane that "uniformly disperse radiofrequency energy" across the entire treatment area.
The company warned that even tiny imperfections "could lead to tissue burns".
This warning was echoed by plastic surgeon Ivor Lim, who has been using Thermage for about 10 years.
He said the machine has to be adjusted to the different thickness of skin on the face and neck, as well as to the patient's tolerance of heat.
It has to be calibrated to the patient's skin so it does not become unbearably hot.
Dr Lim said that when the machine is wrongly used, treatment could result in burns.
Used properly, the machine provides a consistent 41 deg C heat that visibly tightens the skin.
The treatment costs about $8,000 and can last two to three years, he said, adding that the peak results appear four to six months later, as the treatment stimulates the production of collagen.
But Dr Lim said: "It feels like heat from hundreds of tiny needles rising to a crescendo of pain."
The fake machines came with brochures that claim identical or similar performance as the original.
Ms Guang said Solta has not retrieved any of the fakes that have been sold.
But it has given details of the beauty spas and salons that have bought them to the Health Sciences Authority, with which the original device is registered.
Solta plans to take legal action against I Health International.
Under Singapore laws, if convicted, the importer is liable to a fine of up to $100,000, and jail term of up to five years, or both.