Product Education
Where Do Exosomes Come From? Comparing Common Sources
Extracellular vesicles can be obtained from biological fluids such as amniotic fluid or collected from cells grown in culture. Why the source changes the questions a buyer should ask.
When comparing exosome products, particle count gets a lot of attention.
But there's another question buyers should ask first:
Where did the extracellular vesicles actually come from?
Extracellular vesicles (EVs) are released by many types of cells and can be found in biological fluids as well as collected from cells grown under controlled culture conditions.
That means two products both marketed using the word “exosomes” may have very different starting materials and manufacturing processes.
Understanding the source can help you ask much better questions before buying.
Exosomes Are Released by Cells
Exosomes are a subtype of extracellular vesicle associated with a particular cellular biogenesis pathway.
EVs can be found in biological fluids including blood, urine, breast milk, saliva and amniotic fluid. Researchers can also collect EVs released by cells grown in culture.
The important distinction for a buyer is:
Where were the EVs obtained, and what happened between the original source and the finished product?
Source #1: Amniotic Fluid
Amniotic fluid is the biological fluid surrounding a developing fetus during pregnancy.
Research has identified extracellular vesicles within amniotic fluid, making it one naturally occurring biological source of EVs.
According to information supplied by KWEHEALTH, HydroKarma is produced from refined amniotic fluid.
That's an important distinction.
HydroKarma should not be described as a cultured-cell-derived or MSC-culture-derived EV product. Its manufacturing model begins with amniotic fluid rather than growing cells through repeated rounds of laboratory expansion to generate EVs.
That doesn't automatically make one source superior to another.
But it changes the questions buyers should ask.
Source #2: Cultured Cells
Another common approach is to grow cells under controlled culture conditions and collect the extracellular vesicles they release.
Mesenchymal stromal/stem cells (MSCs) are frequently studied as an EV source, although many other cell types can release EVs.
For cultured-cell-derived products, manufacturing questions can include:
- What cell type is used?
- Where did the original cells come from?
- How are they expanded?
- What culture conditions are used?
- How is passage number controlled?
- How are EVs collected and purified?
- How is consistency evaluated between batches?
This is where cell passage number becomes relevant.
Repeated expansion can alter cellular characteristics, and research has shown that cellular aging and senescence can affect the EVs cells release.
That's why passage history can be an important consideration for cultured-cell-derived EV products.
It should not, however, be automatically applied to a product derived directly from a biological fluid without that cell-expansion step.
Source #3: Blood and Platelets
Blood is another source of extracellular vesicles.
Platelets, red blood cells, white blood cells and other components of blood can release EVs.
This is also one reason the relationship between PRP and extracellular vesicles is interesting: activated platelets release extracellular vesicles, and researchers are studying their potential contribution to PRP biology.
But a platelet-derived EV preparation, PRP, and an amniotic-fluid-derived EV product are not interchangeable simply because extracellular vesicles may be present in each.
Their starting materials and preparation methods are different.
See Exosomes vs. PRP: What's the Difference?
Source #4: Other Biological Fluids
EVs have also been identified in numerous other biological fluids, including:
- urine
- saliva
- breast milk
- cerebrospinal fluid
These sources are important in EV research, particularly because extracellular vesicles can carry molecular information associated with the cells and tissues from which they originated.
That leads to an important principle:
The word “exosome” doesn't tell you the source.
The source needs to be identified separately.
Does the Source Determine Which Product Is Better?
Not by itself.
It would be tempting to rank EV products simply according to their biological source, but that would ignore much of what determines the characteristics of a finished preparation.
Source is one part of a larger picture that includes:
Source → Processing → Purification → Characterization → Finished-product testing → Storage and handling
A compelling source does not eliminate the need for documentation.
Likewise, a large particle count doesn't tell you whether the underlying product was appropriately characterized.
What Should Buyers Ask?
When evaluating an EV product, ask:
1. What is the biological source?
Don't settle for “exosomes.”
2. Are cultured cells used?
If so, ask how cell expansion and passage history are controlled.
3. Who manufactures the finished product?
The seller and manufacturer may be different companies.
4. How are the EVs characterized?
Look beyond particle count.
5. Is batch-specific documentation available?
Ideally, the product lot should connect to its corresponding Certificate of Analysis.
You can explore these questions further in How to Evaluate an Exosome Product Before You Buy.
Why Source Transparency Matters
The purpose of asking about source isn't to find a magic biological material that automatically guarantees a better product.
It's to understand what you're actually buying.
According to KWEHEALTH's supplied documentation, HydroKarma is derived from refined amniotic fluid, and batch-specific documentation provides additional information about the finished product and its characterization. Our guide How Are Exosomes Produced and Processed? walks through that pathway in more detail.
That gives buyers two separate pieces of information:
Where the material originated and what was reported about the finished lot.
Both matter.
The Bottom Line
Not all products described as exosomes or extracellular vesicles begin in the same place.
Some EVs are obtained from biological fluids such as amniotic fluid, while others may be collected from cells expanded in culture.
Neither source alone proves that a finished product is better.
But knowing the source tells you which manufacturing questions you should be asking next.
Before buying an exosome product, don't just ask:
“How many exosomes are in it?”
Ask:
“Where did they come from?”
Original Source / References
- Welsh JA, Goberdhan DCI, O'Driscoll L et al. — Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches. Journal of Extracellular Vesicles, 2024;13(2):e12404. DOI: 10.1002/jev2.12404 (PMID 38326288). Cited for EV nomenclature and the recommendation that EV preparations be characterized rather than described by name alone.
- Keller S, Ridinger J, Rupp AK et al. — Body fluid derived exosomes as a novel template for clinical diagnostics. Journal of Translational Medicine, 2011;9:86. DOI: 10.1186/1479-5876-9-86 (PMID 21651777). Cited for the presence of EVs in body fluids including blood, urine, saliva, breast milk and amniotic fluid.
- Sheller-Miller S & Menon R — Isolation and characterization of human amniotic fluid-derived exosomes. Methods in Enzymology, 2020;645:181–194. DOI: 10.1016/bs.mie.2020.07.006 (PMID 33565971). Cited specifically for the identification, isolation and characterization of extracellular vesicles from human amniotic fluid.
- Kim CG, Lee JK, Cho GJ, Shin OS, Gim JA — Small RNA sequencing of small extracellular vesicles secreted by umbilical cord mesenchymal stem cells following replicative senescence. Genes & Genomics, 2023;45(3):347–358. DOI: 10.1007/s13258-022-01297-y (PMID 35917089). Cited only for the general point that replicative senescence following repeated cell expansion can alter the cargo of MSC-derived small EVs; it does not establish any passage limit and does not concern HydroKarma.
- KWEHEALTH/HydroKarma — manufacturer-supplied documentation regarding HydroKarma sourcing and manufacturing. The statement that HydroKarma is produced from refined amniotic fluid is manufacturer-supplied information; it is not a finding of the independent publications above and does not establish safety or efficacy.
Continue Learning
What Does Cell Passage Number Mean in Exosome Manufacturing?
Passage number describes how much cultured cells have been expanded. Why it's a legitimate manufacturing question for cultured-cell-derived EV products — and why it doesn't apply to every EV source.
How Are Exosomes Produced and Processed?
Extracellular vesicles can come from cultured cells or directly from biological fluids. A plain-English look at cell-culture-derived EVs, biofluid-derived EVs, and HydroKarma's amniotic-fluid-derived pathway.
How to Evaluate an Exosome Product Before You Buy
Seven practical things to check before buying an exosome product — manufacturer, biological source, batch-specific COA, particle-count method, finished-product testing, cold-chain handling and verifiable claims.
Exosomes vs. PRP: What's the Difference?
A balanced comparison of platelet-rich plasma and manufactured extracellular vesicle products: where each starts, how consistency differs, and what buyers should ask about.