Does “Contains X Trillion Exosomes” Really Prove Quality? — Dr. Moriwaki on NTA/TRPS Particle Counts and What Is Actually in Stem Cell Conditioned Media2026.07.14

“Contains X trillion exosomes,” “industry-highest concentration” — such particle-count claims are now common in hair regenerative medicine ads. The bigger the number, the more effective it seems, but how are those particles actually measured, and do they truly reflect the quality or effect of stem cell conditioned media? The short answer: particle counts can be one indicator of quality, but they are not something you can compare on numbers alone. In this article, Dr. Moriwaki (member of the Japan Society of Aesthetic Surgery, AVAN TOKYO Ginza) walks through the principles and limits of particle counting, and the items that deserve attention behind the number.

Key Points of This Article

・Exosome particle counts are measured with methods like NTA (Nanoparticle Tracking Analysis) and TRPS (Tunable Resistive Pulse Sensing), and the value changes with method and conditions.

・”X trillion particles” can include non-exosome particles or aggregates — particle count does not equal the amount of active ingredient.

・The contents of stem cell conditioned media should be discussed in terms of growth factors, miRNA, and protein composition. Particle count is only one facet.

・A Certificate of Analysis (CoA) confirming sterility, mycoplasma, and endotoxin testing should be reviewed first.

・Rather than the advertised particle count, look at the manufacturer, testing panel, and dose-level evidence to guide your decision.

How Exosome Particle Counts Are Measured

Stem cell conditioned media contains extracellular vesicles (including exosomes) roughly 30 to 150 nm in diameter, secreted by cells. The main methods for counting these particles are NTA (Nanoparticle Tracking Analysis) and TRPS (Tunable Resistive Pulse Sensing). NTA uses laser light to track the Brownian motion of particles and estimate count and size, while TRPS measures the electrical signal generated as each particle passes through a tiny pore. Both can output a value like “X particles per mL,” but because their principles differ, the same sample often yields different numbers. Dilution rate, capture duration, and analysis software settings can also shift results. “X trillion particles” alone does not tell you which method or conditions produced that number.

Why “X Trillion Particles” Alone Cannot Judge the Quality of Stem Cell Conditioned Media

NTA and TRPS count not “exosomes themselves” but every particle falling within the target size range. Protein aggregates or lipid particles from the culture medium can be swept into the count, so what fraction is truly exosomes requires separate confirmation (marker detection such as CD9/CD63, Western blot, electron microscopy). Moreover, the contents (miRNA, protein cargo) per particle vary significantly with donor and culture conditions, so ten times more particles does not mean ten times the biological effect if each particle is thinner. “Contains X trillion particles” is a single facet of stem cell conditioned media, and treating it as the whole picture is medically dishonest.

Contents Should Be Discussed by “Composition,” Not by “Count”

What matters clinically is the relative composition of growth factors such as EGF, FGF, IGF-1, HGF, VEGF, and TGF-β, and the delivery design that determines which cells around the hair follicle receive them. Even the same stem cell conditioned media can differ in composition depending on cell source (umbilical, adipose, dental pulp), passage number, serum-free or serum-containing culture conditions, and the processes of collection, concentration, and freeze-thaw. Particle count captures only one facet of these variations. Please also refer to the related hair regenerative medicine article list, where we cover differences by cell source and culture conditions in separate posts, so that you can review the picture beyond particle count.

What to Check on a Certificate of Analysis (CoA)

Higher priority than an advertised particle count is the safety test result of the lot itself. A Certificate of Analysis (CoA) typically lists sterility testing (aerobic/anaerobic), mycoplasma testing, endotoxin testing, appearance and pH, and where applicable, particle counts, protein concentration, and measurements of major growth factors. Checking whether the judgment column reads “pass” and how much margin exists between specification and measured value tells you whether the lot is being produced consistently. Conversely, cases where no CoA is available or where testing is limited to “sterility only” are signals to be cautious. Scalp injection involves microscopic wounds, so meeting sterility and endotoxin specifications is information patients should also want to confirm.

Questions to Raise Between Patient and Doctor

At the initial consultation, questions like the following help you decide without leaning on ad copy: “Is this product used at a facility notified under the Act on Ensuring the Safety of Regenerative Medicine?” “May I see the Certificate of Analysis?” “Beyond particles per dose, is there information on major growth factors?” “Was the particle count measured by NTA or TRPS?” For guidelines on AGA and hair loss, the Japanese Dermatological Association publishes guidance; understanding standard oral/topical therapies alongside the position of regenerative medicine makes it easier to choose without being pulled by particle count claims alone. Individual responses vary and every treatment has its limits — the premise that no product allows a definitive claim like “X trillion particles guarantee hair growth” should be shared between patient and physician.

Frequently Asked Questions

Q. If an ad says “contains X trillion particles per session,” does that mean it works better than other clinics?

Not necessarily. Particle count values shift with methods such as NTA/TRPS and with dilution conditions, and non-exosome particles can be counted as well. Without a clear disclosure of the composition of growth factors and miRNA that make up the active ingredients, simple numerical comparison is difficult.

Q. Which tests should I check to confirm the safety of stem cell conditioned media?

Sterility, mycoplasma, and endotoxin testing are the three you want to confirm at minimum. Checking that the CoA lists these as “pass” tells you how the safety of each lot is being ensured.

Q. Beyond particle count, what other indicators matter for scalp treatment?

Cell source (umbilical, adipose, dental pulp), culture conditions (serum-free or with serum), passage number, freeze-thaw cycles, and delivery design (scalp injection, drug delivery). Particle count is only one aspect — evaluating the preparation and treatment design from multiple angles is ideal.

Q. Are there legal rules for advertised particle counts?

Japan’s Medical Advertising Guidelines prohibit exaggerated expressions or efficacy guarantees that could mislead patients. When phrases such as “industry-highest concentration” or “X trillion particles guarantee hair growth” line up, the first step is to carefully verify the source and testing infrastructure.

Q. Does a higher particle count mean a higher treatment effect?

Not in a simple linear way. Even with more particles, if the cargo (miRNA, protein) within each particle is thin, the biological effect may not scale proportionally. Effect is decided by composition, delivery route, hair cycle, and individual response — treating the count alone as an efficacy indicator is not advisable.

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Supervising Physician: Shin Moriwaki, MD

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

ECFMG Certificate

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📍AVAN TOKYO Ginza Hair Regenerative Medicine

AVAN TOKYO Ginza Hair Regenerative Medicine

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