How Are Billions Counted in Exosomes?

Dec 23 , 2025

How Are Billions Counted in Exosomes?

A Scientific Explanation of Exosome Concentration, Volume, and Lyophilized Formulation

Introduction

One of the most frequently asked questions by clinicians when evaluating exosome-based therapies is:

“If every vial contains the same volume (5 mL), how can one formulation contain 5 billion exosomes while another contains 25 billion?”

This question is both valid and critical, particularly for physicians who demand clarity on dose standardization, biological potency, and manufacturing integrity.

This article provides a clear, scientific, and process-driven explanation of how exosome “billions” are quantified, why volume remains constant, and what differentiates lower- and higher-concentration exosome formulations.

Understanding Exosomes at a Cellular Level

Exosomes are nano-sized extracellular vesicles (30–150 nm) released by cells, particularly mesenchymal stem cells (MSCs). They function as biological messengers, carrying molecular signals that regulate tissue repair, inflammation, angiogenesis, and cellular regeneration.

Core Bioactive Components Inside Exosomes:

  • Growth factors

  • Signaling proteins

  • Peptides

  • Lipids

  • mRNA

  • microRNA (miRNA)

  • Cytokines and regulatory enzymes

It is important to clarify a common misconception:

Exosomes do not contain whole stem cells.
They carry signals produced by stem cells, not the cells themselves.

Why Volume (5 mL) Remains Constant

All AevoCytical ExoGenesis formulations
5 Billion, 10 Billion, 15 Billion, and 25 Billion
are supplied in a fixed final volume of 5 mL.

This is done for:

  • Standardized clinical handling

  • Accurate dosing protocols

  • Consistent injection or microneedling workflows

Volume ≠ Quantity

The difference lies in concentration, not volume.

Exosome Concentration Explained

Exosome count is expressed as:

Number of exosome particles per milliliter (particles/mL)

Example Comparison

Product Total Exosomes Volume Concentration
ExoGenesis 5B 5 × 10⁹ 5 mL 1 × 10⁹ / mL
ExoGenesis 25B 25 × 10⁹ 5 mL 5 × 10⁹ / mL

Mathematical Representation

Total Exosome Count = Concentration (particles/mL) × Volume (mL)

So:

  • Higher billions = higher particle density

  • Same volume = different biological payload

Role of Lyophilized Powder vs Diluent

Each AevoCytical exosome kit consists of two components:

1. Lyophilized (Freeze-Dried) Powder

This is the biologically active component

Contains:

  • Intact exosome vesicles

  • Functional peptides

  • Proteins and growth factors

  • miRNA and mRNA cargo

Lyophilization:

  • Removes water under controlled conditions

  • Preserves vesicle structure

  • Maintains biological stability

  • Allows long-term storage without degradation

Microscopic view of lyophilized exosome particles

2. Diluent (Sterile Reconstitution Solution)

This is NOT the active component

  • Sterile, medical-grade aqueous solution

  • Used only to rehydrate the lyophilized powder

  • Does not contain exosomes or peptides

Why Higher Billions Are More Potent

A 25 Billion exosome vial does not mean “larger exosomes”
It means:

  • More vesicles per milliliter

  • Higher signal density

  • Increased molecular delivery to target tissue

Clinically, this translates into:

  • Stronger paracrine signaling

  • Enhanced cellular communication

  • Greater regenerative stimulation

  • Faster and more visible outcomes

Diagram showing low vs high exosome concentration per mL

How Exosomes Are Scientifically Counted

Exosome quantification is not estimated—it is instrumentally measured.

Standard Quantification Technologies:

  • Nanoparticle Tracking Analysis (NTA)

  • Tunable Resistive Pulse Sensing (TRPS)

  • Flow cytometry (advanced labs)

These tools:

  • Track Brownian motion of nanoparticles

  • Calculate size distribution

  • Count exact particle numbers per milliliter

NTA graph showing particle concentration curve Korean exosomes

Manufacturing Process Overview

Step-by-Step Summary:

  1. Stem cell culture under GMP conditions

  2. Exosome secretion into conditioned media

  3. Isolation and purification (ultrafiltration / chromatography)

  4. Particle counting and concentration standardization

  5. Lyophilization of measured exosome quantity

  6. Sterile packaging with diluent

MP manufacturing workflow of Korean exosomes

Clinical Interpretation for Doctors

When a physician selects:

  • 5 Billion → maintenance, early-stage cases

  • 10–15 Billion → moderate regeneration

  • 25 Billion → advanced hair loss, skin aging, or post-procedure recovery

They are selecting:

Different biological signal intensities,
not different volumes.