Poor UK regulation of cosmetic treatments is turning the public into "guinea pigs", warn campaigners.
Dermal fillers are used to fill out lips and wrinkles
Which? magazine claims that companies are testing cosmetic fillers in the UK before applying for a US licence under more stringent rules.
Only seven fillers - injectable substances used to reduce wrinkles - containing hyaluronic acid are licensed in the US compared with 65 in the UK.
Government regulators are currently reviewing the situation.
Every year around 400,000 people undergo non-surgical cosmetic treatments such as fillers, a figure which is increasing.
Most cosmetic fillers in the UK are covered by EU legislation, which allows companies to self-certify or use independent testing laboratories.
One example of weak regulation, says Which?, is Isolagen - a treatment that used patients' own cells to smooth out skin.
The treatment was withdrawn in the US in 1999 but introduced to Britain in 2002.
Which? claims the company has used information gathered in Britain to support its pending licence application to the Federal Drug Administration in the US.
And it said the company had claimed the product had been cleared by the health regulator despite not being covered by any regulation in Britain.
Isolagen has now closed its European operation and has withdrawn from the British market, the magazine said.
Jenny Driscoll, health campaigner at Which?, said: "At the moment Britain is effectively a testing ground for cosmetic treatments.
"New products are coming onto the market all the time and the regulation needs to keep up with the science.
"If the Department of Health doesn't step up and recognise the flaws in the system, it is leaving Brits potentially at risk."
A spokesperson for the Medicines and Healthcare Products Regulatory Agency said the regulatory status of dermal fillers was currently undetermined.
The MHRA and the Department for Business Enterprise and Regulatory Reform are in discussions as to whether such products should be regulated as medical devices or as cosmetics.
They added: "In addition, in response to the Cayton Report, the Department of Health are developing a voluntary self regulation scheme for cosmetic surgery and associated services as a whole."
Douglas McGeorge, president of the British Association of Aesthetic Plastic Surgeons, said the problem was not with the fillers themselves but with those offering the procedure.
"[Health minister] Lord Hunt decided they would not bring these things under care standards and self-regulation should be the way forward," he said.
He added: "Isolagen worked well for what it was, which was just a filler, but claimed all sorts of weird and wonderful things and was advertised directly to the public.
"If you went to a sensible clinic, they would say I don't think this is a good idea, but a less reputable one would give it."
But he said fillers were not in themselves unsafe and the FDA was too restrictive in what it licensed.