NEW YORK – The viral trend of “Barbie Botox” that has women as young as in their 20s rush for toxin-based procedures to mimic the looks of the movie’s lead actress Margot Robbie may lead to resistance among users and hinder medical use in future, doctors have cautioned.

The procedure, also known as “Trap Tox”, has been widely used by doctors to inject a class of drugs known as botulinum toxins, such as Botox, into the trapezius muscles of the upper back to treat migraines and shoulder pain.

But since the Barbie movie was released in July, there has been an uptick in demand for use as a cosmetic procedure. The hashtag BarbieBotox had 11.2 million views on TikTok.

The procedure “supposedly slims the neck and somehow that got attributed to the actress that’s playing Barbie”, Revance Therapeutics chief executive Dustin Sjuts told Reuters in an interview.

“They’re not treating wrinkles or lax skin. They want less girth to their neck, a slimmer, more contoured neck,” said Dr Scot Glasberg, president-elect of Plastic Surgery Foundation, who practises in New York.

The approval of such injections for cosmetic purposes is only limited to procedures involving the face, making the use of the injection in the trapezius “off-label”.

The US Food and Drug Administration places the responsibility of “off-label” use on health professionals to judge such procedures as “medically appropriate”.

Meanwhile, Revance and Evolus, which make similar toxins under the brand Daxxify and Jeuveau, respectively, told Reuters that though “Barbie Botox” has picked up in recent months, they do not see the trend significantly boosting sales.

Botox maker AbbVie declined to comment.

Historically, people above 40 years would opt for toxin-based injections – a market estimated to be worth over US$3 billion (S$4 billion) in annual sales in the US.

However, the doctors said they were concerned about a rise in use among younger women – and six doctors warned that procedures by under-qualified staff at some medispas raised the risk of complications.

Resistance risk

The jump in use among younger women with typically stronger immune systems also raises the risk that the products could become less effective over time, said Dr Shilpi Kheterpal, a dermatologist at Cleveland Clinic.

“If they’re doing high amounts of Botox very frequently… they may lose its effect over time, not just with Botox, but with the other products on the market too, because they all have some similar molecule,” Dr Kheterpal said.

Doctors also stressed the risk with administration by people who may not be properly qualified, especially at medispas where there is little oversight.

“There are no regulations on the type of doctor that can run a medispa,” said Dr Melissa Levoska, assistant professor of dermatology at the Icahn School of Medicine at Mount Sinai in New York.

“So, a family medicine physician or ob-gyn can technically open up a medispa, and now increasingly, there are also physician assistants and nurse practitioners who are doing injections.”

The toxins are generally safe, but a potential risk, if not injected properly, could be the impact on neighbouring muscles, which might weaken them for months.

“The science isn’t quite there yet, in order to support the clinical profile of it,” said Evolus CEO David Moatazedi.

“However, we do know neurotoxins have been used at doses significantly higher for therapeutic purposes than the level of being used for aesthetic purposes, and we know the products are safe.” REUTERS