In recent years, the terms “exosome” and “secretome” have appeared more frequently in the field of regenerative medicine. Both relate to substances secreted by cells such as stem cells, but what distinguishes them?
This article clarifies the differences between exosomes and the secretome, and explains in simple terms why the secretome is a comprehensive concept that encompasses all the advantages of exosomes.
What Are Exosomes?
Exosomes are very small particles (capsule-like structures) released from cells, packed with a cell’s “messages” and the “materials” that act on other cells.
They are ultra-small—less than 0.0001 mm in size—and enclosed by a specialized membrane.
Their role is, in short, “intercellular messengers.”
For example, when some part of the body is injured, signaling cells package repair instructions into exosomes and deliver them to other cells.
The recipient cells respond to those messages to drive repair and modulate inflammation. [2]
Because of this “message-delivery” function, exosomes are being studied for skin regeneration and hair restoration in aesthetics, and for neurological and immune disorders in medicine. [6]
What Is the Secretome?
The secretome refers to the collection of beneficial factors released by cells—particularly by stem cells. [1]
When the body is injured or ill, cells release a variety of substances around them to aid repair and regulation.
You can think of the secretome as a bundle of those natural healing factors.
It contains growth factors that promote tissue repair, cytokines that suppress inflammation, and exosomes that convey information between cells; together they support recovery in a coordinated way.
In short, the secretome is the “essence of the body’s self-repair program” produced by cells.
Recently, regenerative and aesthetic treatments that use the secretome—for skin rejuvenation, wound healing, and relief of joint pain—have begun to spread.
Although still relatively new, it is highly regarded for its gentle, natural mode of action, and broader adoption is anticipated.
Differences Between the Secretome and Exosomes
As noted above, exosomes are one component of the secretome.
Whereas the secretome is a mixed solution containing diverse factors including exosomes, “exosomes” alone refer to the vesicular fraction isolated from that mixture.
When exosomes are isolated and purified, a concentrated exosome preparation is obtained—but other important soluble factors and small vesicles can be lost in the process.
In other words, the secretome includes all of the benefits of exosomes, plus additional effects from factors that exosomes alone cannot provide. [4]
Secretome vs. Exosomes: A Comparison
| Secretome | Exosome | |
|---|---|---|
| Extracellular vesicles: Microvesicles |
Included | Included |
| Extracellular vesicles: Exosomes |
Included | Included |
| Chemokines | Abundant | Present, small amount |
| Cytokines | Abundant | Present, small amount |
| Growth factors | Abundant | Present, small amount |
As the table shows, the secretome contains all the advantages associated with exosomes.
Exosomes are prized for expected effects—similar to stem cell therapy—such as promoting tissue repair and suppressing inflammation, while maintaining a favorable safety profile with low risk of rejection-type reactions.
Likewise, because the secretome uses only factors released by cells, it is expected to offer comparable safety and effectiveness.
Moreover, the secretome also contains many other beneficial substances—such as cytokines and growth factors—beyond exosomes; through their combined actions, broader benefits may be realized. [5]
In practice, isolating only exosomes removes other valuable constituents, whereas the secretome allows those components to be used together as-is.
For these reasons, the secretome is sometimes treated as a concept “above” exosomes.
However, the relationship is not competitive: it is a “part and whole” relationship, with exosomes residing within the secretome.
In clinical practice, depending on the therapeutic goal, options include using “high-concentration exosomes” or “the full secretome,” selecting the approach that best fits the situation.
The secretome is expected to act more broadly via cooperation among diverse components, while exosomes excel at efficiently delivering specific information.
Both offer high safety and utility; using them appropriately can lead to better treatment outcomes.
Wharton’s Jelly–Derived Secretome and Our Work at 23C
The composition of a secretome varies substantially depending on the type of stem cell from which it originates. In recent years, secretomes secreted by stem cells collected from the umbilical cord have drawn particular attention.
Inside the cord is a gelatinous tissue called Wharton’s jelly, which is rich in young, highly active mesenchymal stem cells (WJ-MSCs). [8]
Compared with other sources, these stem cells proliferate robustly and secrete many bioactive substances.
Studies have reported that secretomes from Wharton’s jelly–derived stem cells (stem cell–conditioned media) contain markedly greater diversity and amounts of exosomes and growth factors than secretomes from adipose or bone-marrow MSCs. [7]
These secretomes also exhibit rich compositional variety, supporting multifaceted therapeutic effects, and are highly rated for safety.
At 23C, we culture and manage Wharton’s jelly–derived stem cells in our own research facilities and provide treatments utilizing high-quality secretome produced from them.
The secretome contains numerous beneficial components—including exosomes, cytokines, and growth factors—and by administering them together, we aim to maximize the body’s self-repair capacity.
Current scientific evidence indicates that Wharton’s jelly–derived secretome is a highly promising therapeutic material that combines strong safety with efficacy. [9]
Through such evidence-based, advanced regenerative medicine, 23C strives to improve patients’ quality of life (QOL).
Summary
Although the terms can be confused, the secretome and exosomes represent different scopes.
Exosomes are one of the tiny particles released by cells and are primarily responsible for information transfer.
By contrast, the secretome is a cell-derived “set of active factors” that bundles various secretions—including those exosomes—such as growth factors and cytokines. [3]
While exosomes alone have shown promising effects and favorable safety in regenerative medicine, secretome therapy retains the power of exosomes and adds synergistic actions from many other factors.
Current research suggests that the secretome offers a safe and effective, cell-free approach to achieving therapeutic benefits.
Against this backdrop, treatments using the secretome are expected to expand and become a key option in “cell-free regenerative medicine.”
Understanding the differences and characteristics of the secretome and exosomes is a first step in choosing regenerative treatments wisely.
And receiving evidence-based care from a trusted medical provider—such as our clinic, 23C—will lead to safe, satisfying treatment.
We hope this information helps those considering regenerative medicine.
The secretome consists of soluble proteins and extracellular vesicles (EVs) and is drawing attention as a cell-free therapeutic approach using stem cells.
Source: Comparative Proteomic Analysis of MSC Secretome – IJMS (2021)
Exosomes contain mRNA/miRNA, convey signals to target cells, and modulate inflammatory responses and repair.
Source: Exosomes in Biomedical Applications – Biomedicines (2023)
The secretome contains cytokines, growth factors, and EVs released by cells, contributing to healing and repair in multiple ways.
Source: WJ-MSC Secretome and Clinical Applications – Front. Cell Dev. Biol. (2023)
The secretome contains multiple active factors—such as cytokines and exosomes—simultaneously and may outperform single-factor approaches through synergy.
Source: Stem Cells vs. Secretome in Regenerative Medicine – Stem Cells Int. (2021)
The secretome can exert diverse effects—pro-regenerative, anti-inflammatory, immunomodulatory, anti-fibrotic—at the same time.
Source: Cell Secretome Strategies for Wound Healing – Polymers (2022)
Exosomes have attracted attention in aesthetic medicine for their ability to promote collagen production and skin regeneration.
Secretomes from Wharton’s jelly–derived MSCs contain a greater variety and amount of proteins than those from other MSCs.
Source: Comparative Proteomic Analysis of MSC Secretome – IJMS (2021)
Wharton’s jelly is the gelatinous substance within the umbilical cord and is rich in young, less-differentiated stem cells (WJ-MSCs).
Source: Comparative Proteomic Analysis of MSC Secretome – IJMS (2021)
Secretome therapy is attracting attention as a safe and effective cell-free strategy with strong regenerative potential.
Source: Cell Secretome Strategies for Wound Healing – Polymers (2022)