People seeking the fountain of youth in expensive stem cell treatments should think twice, scientists warn.

In over 20 countries, 114 companies were identified by researchers at the University of Reading and the Universiti Sains Malaysia as offering unregulated stem-cell derived products, noting skincare was targeted the most.

The “vast” majority of the stem cell treatments offered “are not yet, and may never be, backed by research that supports therapeutic use,” said Dr. Darius Widera, the lead author of a new study and an associate professor at the University of Reading.

“Companies that sell untested and unproven health promises are little more than modern snake-oil salesmen,” Widera said in a university release.

Scientists are calling for tighter regulations for clinics using stem cell therapies and claim that private clinics worldwide are touting them to help conditions — such as Parkinson’s disease, anti-aging treatments and hair loss — with little evidence of safety and efficacy.

Researchers in the study, which was published in Stem Cell Research & Therapy on May 4, are now calling on regulators to pause the sale of these products until they can be tested in clinical trials.

“[The treatments] may put potentially vulnerable and sometimes desperate people at risk of losing large amounts of cash for treatments that don’t work or are even dangerous,” Widera pointed out. “Regulators must act now to protect people.”

They study noted that most of the companies didn’t disclose the exactly where the cells were taken from, but the ones that did identified blood, amniotic fluid, fat tissue, bone marrow, and umbilical cord as the most common sources.

Another worrying trend is the amount of money people are spending on treatments.

“At best, consumers are gambling their money, in amounts from $99 to $20,000, on treatments for which there is no reliable evidence. At worst, these treatments could be harmful,” he said.

“Any medical procedure carries a risk,” Widera continued. “People can develop allergic reactions and infections, and there are sometimes very serious side effects from having an unproven product introduced to your body.”

Co-author Dr. Graeme Cottrell agreed, adding there is also “huge potential” for exploitation.

“People who live with chronic or degenerative conditions, and their loved ones, desperately want to find something that will offer some relief from symptoms,” he pointed out. “They are often woefully under-served by the available therapies and treatments and are willing to try pretty much anything that sounds like it might work.”