With people getting everything from salmon sperm to plasma injected into their faces in the name of beauty, it is difficult to be surprised when new, even seemingly extreme methods to achieve youthfulness are promoted.

But Dr David Sparks, a specialist plastic surgeon based in Queensland, was alarmed when he heard patients were asking about cadaver fillers, a trend being promoted on social media as “zombie filler”.

“This is being presented as an established procedure, when the human clinical data is still very early,” he said.

What is zombie filler?

Fat injections, or lipofilling, is a known cosmetic procedure that involves taking fat from the patient’s own body and injecting it into the same patient’s face to add plumpness and reduce wrinkles.

But in order to be less invasive and reduce recovery time and scarring from fat removal, some cosmetic and plastic surgeons in the US are using donor adipose (fat) tissue from dead bodies.

Despite some Australians asking about the procedure in online forums and at appointments with specialist doctors, Sparks says the service isn’t approved in Australia. “The clinical evidence is still early stage, and it simply isn’t something that can be legitimately offered here yet,” he says.

“Neither AlloClae nor Renuva, the two products available in the United States, are listed on the Australian Register of Therapeutic Goods. There’s no Therapeutic Goods Administration-registered injectable adipose allograft product in Australia.”

How does the body respond to donor fat?

The procedure has only been available via a select group of cosmetic surgeons in the US as of last year, which means there is no long term data from large numbers of people about how the body responds to the filler over time.

Dr Deshan Sebaratnam, a dermatologist and associate professor at the University of New South Wales, says ideally there would be randomised controlled trials into a new treatment, where neither the researcher nor patient will know whether they are being given the new treatment, to avoid the placebo effect. This data is then peer-reviewed and made available through publishing in a scientific journal.

“I’d like to see more long-term data in terms of safety and effectiveness,” Sebaratnam said.

Sparks says there is a “gap between what’s being claimed online and what the evidence actually supports” about the procedure.

What are the safety risks?

Normally, Sebaratnam says, you can’t just transfer one person’s body part to another person because the body will recognise it as foreign, prompting an attack by the immune system and rejection.

Sparks says cadaver filler undergoes a process to prevent this risk.

While the “cadaver” framing is “technically accurate”, Sparks says it sensationalises “what is actually a carefully processed medical product … for AlloClae specifically, donor fat is treated with a detergent solution that strips the cells of their DNA”.

The structure of the cells is preserved, leaving a kind of “scaffold” made up of proteins.

Once this filler is injected, the patient’s own body gradually fills the scaffold with its own fat cells over time, he says.

Dr Lily Vrtik, president of the Australasian Society of Aesthetic Plastic Surgeons, says the procedure is still not risk-free even after this cleansing process.

“The usual risks associated with using cadaveric tissue allografts include specific issues such as tissue rejection and transmission of communicable diseases,” she says.

“More general issues include infection, failure to ‘take’ or integrate into native tissue, survival of the graft and other complications associated with surgery in general.”

Sparks says the more established and therefore safer option is still to use a patient’s own fat.

A question of ethics

Sparks says it is worth noting that donor-derived tissue isn’t new, and is already used routinely in surgery. For example, rib cartilage allograft in rhinoplasty, and tendon allograft in knee reconstruction.

“What’s novel here is the tissue type and the processing method,” he says.

However, even if the procedure eventually proves safe and effective, Sebaratnam says he has ethical reservations.

“Do the people donating their bodies know what it’s going to be used for?” he says.

“It’s one thing to sign up to be a kidney donor. It’s another for grandma’s body to be used to help boost someone’s hot photos on Instagram.”

Ivanka Prichard, a professor of body image and health with Flinders University, said she fears content promoting such cosmetic procedures can make them seem normal.

“If someone doesn’t measure up to the content that they are viewing when they compare themselves to it, this can make people feel dissatisfied with their bodies and as a result want to use cosmetic enhancements regardless of the risks,” she said.

“These impacts on body image could in turn lead to disordered eating, body dysmorphia, depression and appearance anxiety.”

• Melissa Davey is Guardian Australia’s medical editor

• Antiviral is a fortnightly column that interrogates the evidence behind the health headlines and factchecks popular wellness claims