The consumer watchdog Which? has uncovered an ex-nurse illegally advertising Botox parties on eBay.
By posing as a potential customer, a Which? researcher heard how the ex-nurse had injected drunken customers with the facial treatment.
Botox is a prescription-only drug and Which says its use should be more stringently regulated.
Cosmetic surgeons warned that it could be dangerous to carry out procedures like this without medical supervision.
The consumer group contacted the Medicines and Healthcare products Regulatory Agency (MHRA) about the Botox parties advertised on eBay. The MHRA said it would look into the matter.
Responding to the Which? report, an eBay spokeswoman said: "eBay does not permit the listing of any controlled drug or item that requires a prescription from, or the supervision of, a licensed practitioner (such as a doctor, dentist, optician or vet) to dispense.
"Where we are informed about the presence of such a substance on our site, we will remove it immediately and take action against the seller."
The Which? researcher was told by the ex-nurse that the cosmetic filler had no side effects "except for drooping" even though bleeding, bruising and infections can occur from the injections.
Which? health campaigner Jenny Driscoll said: "There's an increasingly casual approach to non-surgical treatment, like Botox parties.
"Tougher, not weaker, regulation is needed. And we question whether the industry, left to itself, will really be able or willing to provide the sort of protection that consumers really need."
The government this year backed away from introducing legislation to clamp down on cosmetic treatments such as fillers and Botox, opting for self-regulation instead.
Douglas McGeorge, consultant plastic surgeon and president of The British Association of Aesthetic Plastic Surgeons, said: "The increasing popularity of non-surgical cosmetic procedures has led to public complacency about where procedures are performed, and by whom.
"These procedures, such as Botox injections or skin resurfacing, while not surgical, are medical undertakings and should only be done in appropriate facilities under the supervision of a properly trained and qualified medical professional - as for prescription drugs, they must be used only under the direct supervision of a doctor.
"These procedures require sanitary surroundings and sterile instruments - all of which can be compromised if taking place in someone's front room."