What Are Extracellular Vesicles?

Last updated: November 2026

Extracellular vesicles (EVs) are tiny membrane-bound particles that cells release to carry proteins, lipids and genetic material to other cells.^2,3 "Extracellular vesicle" is the umbrella term; exosomes, microvesicles and apoptotic bodies are types of EVs that differ in size and in how they form.^1,2 EVs are studied as messengers between cells, as markers in blood tests and as carriers for delivering active compounds.^2,4

Types of extracellular vesicles

Almost every cell type releases EVs, and they are found in blood, saliva, urine and breast milk, as well as in plants and microbes.³ They are usually grouped by how they are made.²

For scale, a red blood cell is about 7,000 nm across, so even large EVs are far too small to see with a normal microscope.

Exosomes vs extracellular vesicles: why the naming matters

"Exosome" is the word most people search for, and it is used loosely on product labels. Scientists are more careful. The International Society for Extracellular Vesicles (ISEV) publishes guidelines called MISEV, and the 2023 edition (Journal of Extracellular Vesicles, 2024) recommends "extracellular vesicle" as the general term.¹ It advises using "exosome" only when the vesicles' origin inside the cell has actually been shown, which is rarely possible in practice.¹ Instead, it suggests describing EVs by measurable features, for example "small EVs" for particles under 200 nm.¹

In short, many products called "exosomes" are better described as EV preparations of mixed types.^1,2 Our exosome compound profile explains the term in more detail.

What EVs carry and do

• Proteins, including surface markers such as CD9, CD63 and CD81 that researchers use to identify EVs.^2,3
• Nucleic acids, especially small RNAs such as microRNAs that can influence activity in the receiving cell.³
• Lipids in their outer membrane, which protect the cargo.³

Because their cargo reflects the cell they came from, EVs act as a communication system between cells and tissues.³ That same feature makes them useful as markers in research on blood-based testing, sometimes called liquid biopsy, where a simple blood draw could one day replace a tissue sample.²

How EVs are isolated and characterized

EVs have to be separated from everything else in a fluid, which is technically demanding.² Common methods include:

1. Ultracentrifugation: spinning samples at very high speed so EVs settle out.^1,2
2. Size-exclusion chromatography: passing a sample through a column that separates particles by size.²
3. Tangential flow filtration: a filtration method used for larger-scale production.^1,2
4. Precipitation and affinity capture: chemical or antibody-based methods that pull EVs out of solution.²

Researchers then confirm what they have with particle counting and sizing (for example, nanoparticle tracking analysis), electron microscopy and tests for the protein markers above.^1,2 MISEV2023 asks studies to report these steps so results can be compared.¹

Where EVs are used

• Research and testing: EVs in blood and urine are studied as markers for many conditions.²
• Drug delivery: EVs are natural carriers, so researchers are engineering them to deliver medicines and RNA.⁴ See exosome delivery technology and how they compare with liposomes and other nanoparticle carriers.
• Cosmetics: EV preparations, often from stem cell cultures or plants, appear in serums and professional treatments. Our beauty page on exosomes in skincare covers that use.

Plant-derived EVs

Plants release EV-like particles too, and they can be isolated from foods such as grapes, ginger, grapefruit and broccoli.^5,6 Plant-derived EVs are attractive because they can be produced at scale without human or animal cells.⁵ Research on them is growing but is still mostly at the laboratory and early clinical stage.⁵ Their cargo and size vary with the plant, the part used and the isolation method, so results from one source do not transfer automatically to another.⁵

Regulatory status

In the United States, the FDA has stated that there are currently no FDA-approved exosome products, and it has warned consumers about clinics marketing unapproved exosome and stem cell treatments.⁷ EV-based medicines are being developed through the normal clinical trial process.⁷ Cosmetic products may contain EV ingredients, but they cannot make drug claims.⁸