Wrinkle-filling injections could lead serious side-effects, the US Food and Drug Administration (FDA) has warned.
Such side-effects could include inability to control their facial muscles, the agency said in a report released on Friday.
The FDA said it received 930 reports of side-effects in the U.S. and other countries from January 2003 to Sept. 20 for products made by various companies.
The products, known as dermal fillers, can be made from animal collagen or chemicals that are injected into the skin to make it look younger or reduce scarring.
Many were known complications such as minor swelling, but facial palsy, disfigurement and rare but life-threatening events such as severe allergic reactions and anaphylactic shock were also reported.
The FDA did not specify how many side-effects were serious or which products were linked to serious problems, noting the reports had limitations such as not saying when the problems arose.
Some of the injections that resulted in side-effects may have been performed by untrained personnel or outside health clinics or doctors' offices, the report said.
The review was released ahead of a Nov. 18 meeting of FDA advisors who will discuss the safety of the products and whether new warnings are required.
Dermal fillers include Allergan Inc.'s Juvederm, Restylane and Perlane from Medicis.
Medicis chief executive Jonah Shacknai said the company has not seen any adverse events that are unexpected, not indicated on the product label or life threatening.
Allergan spokeswoman Caroline Van Hove said Juvederm has a "highly favourable safety profile," and no serious problems were seen in clinical trials. Since it was approved, swelling was the most common, affecting 0.4 per cent of patients.