What Are Secretomes, and How Do They Differ from Exosomes?
Clinical content from Jeffrey Vogel, MD, MPH – Chief Medical Officer, Boundless
"Secretomes represent the most biologically complete approach we have in hair restoration. Most men haven't heard the term. It's worth explaining clearly, because understanding the difference between exosomes and secretomes changes how you think about the regenerative hierarchy."
What a secretome is
Every cell in the body secretes signals. These secreted signals – growth factors, proteins, cytokines, exosomes, repair molecules, and other bioactive compounds – are collectively called the secretome. It is the full communication toolkit a cell uses to coordinate activity with surrounding tissue.
In the context of hair restoration, what matters specifically is the secretome produced by hair follicle stem cells. At Boundless, your secretome is derived from your own hair follicles, processed at a partner lab, and returned to you as a personalized regenerative preparation.
What secretomes contain that exosomes alone do not
PRP delivers concentrated growth factors from your platelets. Exosomes deliver a subset of the cellular communication system – the vesicle-based signaling layer that carries microRNA and regulatory proteins.
Secretomes deliver all of the above, plus more. A full-spectrum secretome preparation from hair follicle stem cells contains: growth factors, natively produced exosomes (from your own follicle cells), PDRN (polydeoxyribonucleotide), cytokines that regulate the local inflammatory environment, carrier proteins, and hundreds of additional bioactive compounds. The concentration of these signals is also significantly higher than what is achievable with PRP or standalone exosome preparations (Altendorf et al., Physiological Reviews, 2025).
If an exosome is one of the most important tools in the repair toolkit, a secretome is the entire toolkit.
The personalization difference
Standalone exosomes used clinically come from optimized donor stem cell lines. They are standardized – consistent and potent, but not specific to the individual.
Your secretome is derived from your own hair follicles. It carries the biological signature of your specific follicle stem cell population.
What the collection process involves
During an in-person collection session, a small number of your hair follicles – typically around 50 – are harvested from the scalp. Those follicles are cultured at a partner lab to generate your personalized secretome over approximately 60 days.
At Boundless, secretomes are available as Secretomes + Microneedling and Secretomes + Alma TED. [See post #15 for why the combination with microneedling matters.]
Final Thoughts
Secretomes represent the most biologically complete option in the regenerative hierarchy. Understanding what they contain – and why that differs from exosomes – helps clarify when moving to the Advanced tier makes sense. [See post #16 for who should consider secretomes.]
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