Fraudulent versions of the wrinkle treatment Botox, which is made by Allergan Inc and also used to treat headaches, underarm sweating and overactive bladder, are being sold in the United States, the Food and Drug Administration said on Friday.

The FDA said in an alert posted on its website that the outer carton of the fraudulent Botox is counterfeit, and the vial inside is foreign and not approved for sale in the United States.

“FDA cannot confirm that the manufacture, quality, storage, and handling of these products follow U.S. standards,” the agency said.

The agency said the products could be counterfeit, contaminated, improperly stored and transported, ineffective and unsafe.

Allergan said that in addition to violating federal law, products that are illegally imported may either be counterfeit or the quality may have been compromised.

Authentic Botox is stored and transported by Allergan according to rigorous specifications, the company said.

Botox is a sterile, purified version of the same toxin that causes botulism, which can cause potentially deadly swallowing and breathing difficulties, and when injected, acts to temporarily smooth certain frown lines. It generated sales in 2012 of $1.77 billion, of which roughly half came from cosmetic use.

The FDA said the fraudulent Botox is being sold under the names “Online Botox Pharmacy,” “Onlinebotox.com” and “Onlinebotox.” The FDA said it did not appear that the fraudulent product was being sold over the Internet, but that sales had been solicited via fax, by offering prices below those of FDA-approved products.

In 2004, four people were hospitalized with poisoning after being injected with unapproved botulinum toxin, which a doctor had passed off as Botox.

The case prompted a wide-scale investigation of more than 200 clinics throughout the United States and resulted in dozens of convictions of people who injected patients with unapproved, cheaper substitutes for Botox.

As recently as last December, the FDA alerted more than 350 medical practices that they may have received unapproved medications, including Botox, from a foreign supplier.

The FDA’s alert comes as lawmakers are seeking to create a national set of standards for tracking prescription drugs through the distribution chain to help prevent counterfeit or contaminated products from reaching the public.

The U.S. House of Representatives and Senate each released draft drug-tracking bills this week. The House draft would require drugs to be traced, but only in lots, that can contain thousands of individual packages. The Senate bill would require each individual drug unit to be traceable.