The Donor Cell Changes What’s Inside — How Age, Tissue of Origin and Passage Number Shape the Composition of Stem Cell Conditioned Media2026.06.28

“If the label says ‘conditioned media,’ the contents must be the same, right?” Many patients assume this. In reality, stem cell conditioned media is essentially a mixture of molecules secreted by cultured stem cells, and its composition changes dramatically depending on the identity of the cells it came from. In this column, we will medically organize how three axes — donor age, tissue of origin, and passage number — influence what is actually inside the bottle.

Stem cell conditioned media is not the cells themselves, but a collection of molecules the cells released

Stem cell conditioned media (CCM: Cell Culture Conditioned Media) is a preparation obtained by collecting and concentrating the secretome of cultured mesenchymal stem cells — growth factors, cytokines, exosomes, miRNAs, and peptides. Rather than transplanting the cells themselves, we use only the signaling molecules they have secreted, which offers advantages in safety and handling.

What is easy to overlook, however, is that “the profile of secreted molecules changes substantially depending on the source cell.”

Even when the cells are nominally the same “stem cells,” differences in origin and culture conditions lead to differences in the types and concentrations of secreted growth factors, the particle size of exosomes, and the composition of miRNAs.

For this reason, the identity of the donor cells cannot be ignored when discussing the quality of conditioned media.

How donor age affects composition

Cells from young donors have higher secretory activity

Basic research has shown that, in mesenchymal stem cells, both secretory and proliferative capacity decline as the donor’s age increases.

Mesenchymal stem cells from young donors tend to secrete major growth factors such as VEGF (vascular endothelial growth factor), HGF (hepatocyte growth factor), and IGF-1 (insulin-like growth factor 1) at higher concentrations.

These signals are involved in improving blood flow in the follicular microenvironment and activating matrix cells, so theoretically, conditioned media derived from young donors is advantageous in hair regenerative medicine.

The problem of “aged secretions” with advancing donor age

On the other hand, cells from older donors are known to release larger amounts of inflammatory cytokines such as IL-6, IL-8, and TNF-α — a phenomenon known as SASP (Senescence-Associated Secretory Phenotype).

These can disrupt the follicular stem cell niche through chronic inflammation, and their presence in conditioned media is not desirable.

Reliable manufacturers select young, healthy donors and implement quality control to suppress SASP-related factors.

Stem cell conditioned media becomes a different product depending on the tissue of origin

Adipose, umbilical cord, bone marrow, dental pulp — each tissue has its own character

Mesenchymal stem cells can be obtained from multiple tissues: adipose tissue, umbilical cord, bone marrow, dental pulp, and more.

Even when stem cells from different tissues share similar surface markers and differentiation tendencies, the profile of cytokines they secrete differs significantly.

For example, umbilical-cord-derived stem cells, being young cells, have high proliferative capacity, and are reported to secrete more IGF-1 and HGF than adipose-derived cells.

Adipose-derived sources are relatively easy to harvest and allow for stable lot volume, but they are more susceptible to the donor’s metabolic state.

How to think about tissue selection in hair regenerative medicine

When using this preparation to address the follicular microenvironment of the scalp, three actions matter: angiogenesis, reactivation of the follicular stem cell niche, and suppression of microinflammation.

The source of the conditioned media must be considered through the lens of whether it contains a balanced mix of growth factors and exosomes that strongly contribute to these effects.

For AGA treatment guidelines, the framework provided by the Japanese Dermatological Association is a useful base; however, since regenerative medicine conditioned media are not pharmaceutically approved drugs, the selection is currently left to the physician’s literacy.

How passage number determines the quality of stem cell conditioned media

The more passages, the lower the secretory capacity

Cultured stem cells are expanded by repeatedly being subcultured (passaged) each time the culture vessel fills up.

The more passages they undergo, the more the stem cells gradually “age,” approaching the Hayflick limit where both proliferative and secretory capacity decline.

Conditioned media collected from early-passage cultures tends to have higher concentrations of growth factors and exosomes, while media collected from late-passage cells may have reduced activity.

Reliable manufacturers record and manage on a per-lot basis exactly which passage (e.g., P3 to P5) the media was harvested from.

Serum-free media and hypoxic culture are additional variables

Alongside passage number, the medium composition (presence or absence of fetal bovine serum) and oxygen concentration (hypoxic culture is reported to enhance secretory capacity) also influence the composition of the conditioned media.

In recent years, conditioned media cultured in serum-free media without bovine-derived components — reducing the risk of xenogenic protein contamination for human use — has been moving toward standardization.

This transparency in the manufacturing process eventually surfaces as differences in the efficacy and safety of hair regenerative medicine.

What patients should check when choosing a conditioned media

As explained above, stem cell conditioned media is a category in which, even under the same name, the actual contents differ from product to product.

The key points to check when considering treatment are the following five:

• Whether the donor’s age range and health status are disclosed

• Whether the tissue of origin (adipose, umbilical cord, bone marrow, etc.) is clearly stated

• Whether the passage number (which passage the media was harvested from) is included in the lot information

• Whether the manufacturing standards (serum-free media, GMP compliance, etc.) are clear

• Whether quantitative data on growth factor and exosome content are provided

A preparation without these disclosures cannot really be evaluated for either efficacy or safety.

At AVAN TOKYO, we use conditioned media that meet the quality criteria above and combine them with Morpheus8 drug delivery to provide hair regenerative medicine.

For a deeper look at our treatment philosophy and other topics, please also see our related hair regenerative medicine column index.

Summary

Stem cell conditioned media is a biological preparation whose composition varies significantly with donor cell age, tissue of origin, and passage number.

Even when sold under the same name “conditioned media,” the contents are not uniform, and the design of the manufacturing process is directly tied to the final clinical effect.

When considering treatment, checking not only the price but also the quality information — “from which cells, under what conditions was this conditioned media made?” — is the first step toward a result you can be satisfied with.

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Supervising physician: Shin Moriwaki, MD

Member, Japan Society of Aesthetic Surgery (JSAS) / Member, American Academy of Aesthetic Medicine

ECFMG certificate (US medical licensing qualification)

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📍AVAN TOKYO Ginza Hair Regenerative Medicine

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