Exosomes have become one of the most talked-about ingredients in aesthetic skincare. Secretome is the word many practitioners are now hearing next. The short answer is that exosomes are one part of the secretome. Secretome is the full set of messages a cell sends; exosomes are one of the ways those messages travel.
Knowing the difference helps you make sense of product labels, treatment menus and the aftercare your clinic recommends.
What is secretome?
Every cell in your body releases substances that carry messages to the cells around it. Scientists call this collection the secretome. It includes:
- Growth factors, which are proteins that act as signals between cells
- Peptides, which are short chains of amino acids
- Cytokines, which are small proteins involved in cell communication
- Extracellular vesicles, tiny packages that carry molecules from one cell to another
Stem cells are particularly active communicators, which is why stem cell secretome has become a focus of skin research. A 2021 review in Clinical, Cosmetic and Investigational Dermatology describes this mix and the research interest in it, while noting that much of the work so far has been laboratory based.
What are exosomes?
Exosomes are one type of extracellular vesicle. They are very small, membrane-bound packages that cells use to carry proteins and other molecules to neighbouring cells. Because they are part of what a cell releases, exosomes sit inside the wider secretome.
Exosome skincare products isolate these vesicles. That makes them a focused ingredient, but it also means they carry only part of the conversation between cells.
The key difference
Think of the secretome as a whole conversation between cells, and exosomes as one voice within it. A complete secretome product keeps growth factors, peptides, cytokines and extracellular vesicles together rather than separating out a single component.
| Secretome | Exosomes | |
|---|---|---|
| What it is | The full range of substances a cell releases | One type of extracellular vesicle |
| What it contains | Growth factors, peptides, cytokines and extracellular vesicles | Proteins and other molecules carried inside a vesicle |
| Relationship | Includes exosomes | Part of the secretome |
| Contains cells? | No | No |
Do secretome or exosome products contain stem cells?
No. Both are cell-free. They contain substances that cells release, not the cells themselves. This is an important distinction, and one worth checking on any product you are offered.
How are secretome and exosome ingredients made?
Both start with cells grown under controlled laboratory conditions. As the cells grow, they release their secretome into the surrounding liquid. For a secretome ingredient, that liquid is collected and processed so the full mix of signals is kept. For an exosome ingredient, an extra step separates out the vesicles and leaves the rest behind.
That extra step is the main reason the two ingredients differ. One keeps the whole mix; the other keeps a single part of it.
Why the source matters
UK cosmetics law does not allow ingredients made from human cells or tissues. So when you see a secretome or exosome product, the origin of the ingredient is a fair and important question. Reputable brands should be able to tell you whether the source is human, animal or plant, and confirm that the product has had a safety assessment.
Questions to ask about a secretome or exosome product
- Is the active ingredient a complete secretome or isolated exosomes?
- Where does the ingredient come from?
- Is the product cell-free?
- Has the finished product had a UK safety assessment?
- Is it designed for use after my treatment?
Where do polynucleotides fit?
Polynucleotides are a different ingredient altogether. They are DNA fragments, often derived from salmon or trout, used in both injectable and topical products. They are not part of the secretome. You can read more in our guide to polynucleotides and exosomes.
What this means for your aftercare
After microneedling, laser or a chemical peel, skin often feels tight, warm and dry for a few days. What you put on it during that time is part of the result. When your clinic recommends aftercare, it is reasonable to ask what is in it and why it has been chosen.
If you want to understand the science in more depth, our page on the science of secretome explains it step by step. Always follow the aftercare advice your practitioner gives you.
Frequently asked questions
Are exosomes and secretome the same thing?
No. Exosomes are one component of the secretome. Secretome also includes growth factors, peptides and cytokines, so it carries a broader range of signals between cells.
Is secretome better than exosomes?
They are different ingredients rather than better or worse versions of the same thing. Secretome keeps the full mix of signals together, while exosome products isolate one part of it. The right choice depends on the product, your treatment and your practitioner’s advice.
Do secretome or exosome products contain stem cells?
No. Both are cell-free. They contain substances that cells release, not the cells themselves.
Where do secretome and exosome ingredients come from?
They are produced from cells grown under controlled laboratory conditions. The source can vary between brands, so it is worth asking. UK cosmetics law does not allow ingredients made from human cells or tissues.
Are exosomes the same as polynucleotides?
No. Polynucleotides are DNA fragments, usually derived from salmon or trout. Exosomes are vesicles that cells release to carry molecules to other cells.
When are secretome products used in clinics?
They are most often applied straight after treatments such as microneedling, laser resurfacing and chemical peels, when skin is freshly treated and feels warm, tight or dry.
Can I use a secretome product at home?
Some secretome products come in a home-use size so you can continue after your appointment. Your practitioner will tell you when and how to use it.
How do I know if a product is good quality?
Ask what the active ingredient is, where it comes from, whether the product is cell-free and whether it has had a UK safety assessment. A reputable clinic or brand should be happy to answer.
Sources
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