Exosomes are touted as a trendy miracle cure. We don’t know if they work.

We do know that exosomes are tiny particles that sprout from cells and that their contents can vary greatly depending on the source of the cell (some popular options include human umbilical cords, salmon testicles, and roses) and how healthy or stressed the cell is. . Even cell biologists disagree about what exactly is in it, and how useful (or dangerous) that content might be.

The world of exosome treatments has been likened to a ‘Wild West’ by some researchers. No rigorous testing has been done yet, so we don’t know how safe it is to spray or inject these little mystery blobs. Exosome products have not been approved by regulatory authorities in the US, UK or Europe, where the treatments are becoming increasingly popular. They are also not approved for medical use in Japan or South Koreatwo other countries where exosome treatments are popular. Still, “exosomes have emerged as a kind of panacea for almost everything,” says Leigh Turner, a bioethicist and public health researcher at the University of California, Irvine, who studies direct-to-consumer marketing of non- approved health products follows. “Risks are usually minimized and the benefits are often exaggerated.”

This hasn’t stopped customers from flocking to the growing number of aesthetic centers, stem cell clinics and medical spas offering exosome treatments, hoping for a miracle cure. The global market for exosome skin care products was valued at $256 million in 2023 and is expected to grow to $674 million over the next six years.

Mysterious blobs

Technically referred to as vesicles, exosomes are made inside cells before they are released. They have been mysterious for a long time. The term ‘exosome’ was introduced in the 1980s. Previously, these were small particles that are now thought to be exosomes described as ‘platelet matter’ or ‘matrix vesicles’.

Initially, scientists assumed that exosomes acted like garbage bags, transporting waste out of the cell. But study from 1996 suggested that exosomes might also work to help cells communicate by delivering signals between them. For example, if a cell is dying, it may be able to send a signal to neighboring cells, giving them the opportunity to produce more protective substances to save themselves from the same fate. Cancer cells, on the other hand, could potentially use exosomes to send signals that other cells adopt to support tumor growth. However, it is not yet completely clear which signals are actually sent.

Another big mystery is what exactly is in exosomes. “It depends who you ask,” says James Edgar, who studies exosomes and similar vesicles at the University of Cambridge, UK. Cell biologists agree that exosomes contain proteins, lipids and other molecules that result from cell metabolism. Some believe they also contain DNA and RNA, but not everyone is convinced. “It’s just very difficult to prove or disprove,” says Edgar.

That’s partly because exosomes are so small: only about 70 nanometers wide, about one-hundredth the size of a red blood cell. While the first images of it were published in the 1970swe’re still not even sure what they look like; Raghu Kalluri of the MD Anderson Cancer Center in Houston and his colleagues study the shape of exosomes to find out whether they are round, oval or rod-shaped, for example.