Exosome, extracellular vesicle or secretome? The words, explained

Evidence: Established · Regenerative Room ·

These words are everywhere in regenerative medicine, often used loosely. Here's what they actually mean, and the question to ask when a product claims 'trillions of exosomes'.

If you've looked into regenerative treatments or skincare lately, you've probably seen the word exosomes. You may also have seen extracellular vesicles and secretome. They're often used as if they mean the same thing. They don't.

The simple version

Cells constantly release tiny packages into their surroundings. These packages carry proteins, fats and genetic messages, and they help cells talk to each other.

  • Extracellular vesicles (EVs) is the umbrella name for all of these tiny packages.
  • Exosomes are one particular type of EV, formed in a specific way inside the cell. Scientists say the word should only be used when that origin has actually been shown, which is hard to do.
  • Secretome means everything a cell releases: vesicles plus free-floating proteins and other molecules.

A simple picture: the secretome is all the post a household sends out. Extracellular vesicles are all the parcels. Exosomes are parcels sent from one particular post office.

Why the words matter

In 2023 the International Society for Extracellular Vesicles updated its scientific guidance (called MISEV2023). It encourages scientists to use "extracellular vesicles" unless they can prove where the particles came from.

So when a product label says "trillions of exosomes", the honest questions are:

  • How do you know they're exosomes and not other particles?
  • How were they counted, and what else is in the vial?
  • Is this product approved for this use where you live?

Where the evidence stands

The science of extracellular vesicles is real and exciting. Research is exploring their role in healing, inflammation and even as a way to deliver medicines. But most treatments using them are still experimental. In the United States, for example, the regulator has warned that no exosome products are approved to treat disease.

The bottom line

Learn the words, ask the questions, and be cautious about big promises. Good providers will welcome the questions. Evidence label: the terminology is Established; most treatments are Experimental.

Educational content only, not medical advice. Talk to a qualified clinician about your own care.