What is a Secretome?

A secretome is the mixture of substances released by cells. Secretomes made from umbilical cord mesenchymal stem cells (U C-MSCs), contain growth factors, proteins, fats, genetic messages, exosomes, and other substances that help cells communicate.

• Growth factors
• Cytokines
• Chemokines
• Proteins
• Lipids
• mRNA/miRNA
• Extracellular vesicles
• Exosomes
• Other signaling molecules

A secretome is not the same as exosomes.

“Exosomes are just one part of a secretome”. In simple terms, UC-MSCs release many helpful signals. Together, these signals are called the secretome.

How could secretomes improve hair?

The rationale is particularly compelling for androgenetic alopecia, because the goal isn't simply to "feed" the follicle. It's to improve the signaling environment around the follicle.

Research suggests UC-MSC secretome can potentially:

1. Reactivate dermal papilla cells
   • Dermal papilla cells are important signaling centers controlling follicular growth.
2. Promote the telogen → anagen transition
   • Essentially encouraging follicles to move from the resting phase into active growth.
3. Increase follicular activity
   • Experimental work has shown increased proliferation and activity of hair-matrix and dermal-papilla-related cells.
4. Increase hair shaft diameter
   • This is particularly important because miniaturized follicles produce progressively thinner hairs.
5. Improve follicular microenvironment
   • Secretome components can have angiogenic, anti-inflammatory and tissue-repair effects.
6. Activate intracellular signaling
   • A 2025 human study identified activation of the PI3K/AKT/mTOR pathway and reported increases in both hair density and average hair diameter.

There is an interesting three-month double-blind human clinical study specifically involving human umbilical-cord MSC secretome. It reported increased hair density and average hair diameter, with no treatment-related scalp or hair adverse reactions reported during the study.

How safe is UC-MSC secretome?

The small earlier pilot study of umbilical-cord MSC-conditioned medium involved 15 people and reported no adverse reactions and positive hair-regeneration effects in 86.6% of participants. The newer three-month study also reported no treatment-related adverse reactions.

Core Safety Findings from Recent Studies

• Mild, Local Side Effects: Clinical trials consistently report that side effects are minimal, temporary, and limited strictly to the injection or application site. The most common issues include transient erythema (redness), localized swelling, mild irritation, tenderness, or tingling.
• No Scalp or Systemic Adverse Reactions: A 3-month double-blind clinical study evaluated the human umbilical cord (hUC)-MSC secretome and confirmed no adverse reactions on the scalp or hair.
• Additionally, localized treatments for conditions like Alopecia Areata show that while local inflammatory cytokines are reduced to promote growth, systemic cytokine levels remain completely unchanged.
• Low Immunogenicity: Formulations, especially those using specialized or immortalized hair follicle-derived MSC secretomes (iHF-MSCs), maintain low immunogenicity and inherently possess immunomodulatory properties that protect skin cells from oxidative stress

But these studies are small and relatively short.

The major issue is that the term "secretome" doesn't describe a standardized pharmaceutical product and there is an important FDA distinction

In the United States, there is no FDA-approved UC-MSC secretome product for treating hair loss. The FDA has repeatedly warned that regenerative products derived from umbilical tissue, stem cells and exosomes may be marketed without adequate evidence of safety or efficacy.

That doesn't mean a properly manufactured secretome is necessarily dangerous. It means you cannot equate "MSC-derived" with "FDA-proven safe."

Secretome vs. exosomes for hair

This is where we think the distinction gets particularly interesting.

A systematic review published recently found that clinical studies of exosome therapy for alopecia generally reported improvements in hair parameters and mostly mild transient local reactions, but emphasized the small studies, heterogeneous products and limited follow-up.

Our interpretation:

For hair restoration, we wouldn't automatically say: “Exosomes are better than secretome."

We would say:

Secretome gives you a broader biological signaling environment, whereas a carefully characterized extracellular vesicle/exosome (Dermal Papilla exosomes) preparation may give you a more concentrated and potentially more controllable signaling system.

Why DPC-specific exosomes are particularly interesting the dermal papilla is essentially the “signaling center of the hair follicle”. It communicates with follicular stem cells and other follicular cells to determine whether the follicle stays dormant, enters anagen (growth phase), maintains growth, or miniaturizes.

A good MSC secretome contains a broad mixture of growth factors, cytokines, proteins, extracellular vesicles and other signaling molecules.The advantage is breadth. You’re not relying on one molecule or one signaling pathway.

Our current studies focus on whether combining secretomes with dermal papilla–specific exosomes can promote hair growth and regeneration.

Greco Medical Group: Experience…. Innovation…. Biotechnology